DISTANCE EDUCATION SELF LEARNING MATERIAL

PROGRAMME : M.Sc. Chemistry

YEAR : FINAL

PAPER : V B

TITLE OF PAPER : ANALYTICAL CHEMISTRY

MADHYA PRADESH BHOJ (OPEN) UNIVERSITY BHOPAL (M.P.)

Course Name -M.Sc. Chemistry

PAPER-

DISTANCE EDUCATION SELF LEARNING MATERIAL

MADHYA PRADESH BHOJ (OPEN) UNIVERSITY

BHOPAL (M.P.)

FIRST EDITION - 2013

UNIVERSITY - M. P. Bhoj (Open) University,Bhopal.

PROGRAMME - M.Sc. Chemistry

TITLE OF PAPER - ANALYTICAL CHEMISTRY

BLOCK .1

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(2) (Name) DR.VINAY PRABHA SHARMA,LECTURER

(Address) DEPARTMENT OF CHEMISTRY, MEERUT COLLEGE, MEERUT

EDITOR- (Name) DR.MAHESH SRIVASTAVA,D.Sc.

(Address) DEPARTMENT OF CHEMISTRY, MEERUT COLLEGE, MEERUT

250001

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Course Name - M.Sc. Chemistry (FINAL)

DISTANCE EDUCATION SELF LEARNING MATERIAL

BLOCK 1:-- VB-ANALYTICAL CHEMISTRY

UNIT I - (TITLE) INTRODUCTION UNIT II - (TITLE) ERRORS AND EVALUATION UNIT III - (TITLE) FOOD ANALYSIS UNIT I V - (TITLE) ANALYSIS OF WATER POLLUTION UNIT V - (TITLE)ANALYSIS OF SOIL FUEL ,BODY FLUIDS AND DRUGS

Paper (Number) Title VB Block (Number) – 1 (1 TO 5) BlockIntroduction

ANALYTICAL CHEMISTRY

2012

UNIVERSITY - Madhya Pradesh Bhoj (Open)

University Bhopal ( M.P)

PROGRAMME - M.Sc. Chemistry (Final)

PAPER - V-B

TITLE OF PAPER - Analytical Chemistry

BLOCK NO. - 1

UNIT WRITER

UNIT-I, II, III & IV – PROF.(Dr.) Anju Saxena

Director

Sunderdeep Group of Engineering College,

(Dasna), Ghaziabad.

UNIT-V - Dr. Vinay Prabha Sharma

Lecturer in Chemistry

Meerut College, Meerut

EDITOR - Dr. Mahesh Srivastava

M.Sc.,Ph.D., D.Sc.

Department of Chemistry

Meerut College, Meerut-250001

BLOCK-I

UNIT-I

ANALYTICAL CHEMISTRY

Role of analytical chemistry. Classification of analytical methods-

classical and instrumental. Types of instrumental analysis. Selecting an

analytical method. Neatness and cleanliness. Laboratory operations and

practices. Analytical balance. Techniques of weighing, errors. Volumetric

glassware cleaning and calibration of glassware. Sample preparations -

dissolution and decompositions. Gravimetric techniques Selecting and

handling of reagents. Laboratory notebooks. Safety in the analytical

laboratory.

UNIT-I

ANALYTICAL CHEMISTRY

1.0 Introduction

1.1 Ojectives

1.2 Analytical Chemistry and its Role.

1.3 Classification of Analytical Methods - Classical and

Instrumental Methods.

1.3.1 Classical Methods.

1.3.2 Instrumental Methods.

1.3.3 Advantages of Instrumental Methods.

1.4 Types of Instrumental Analysis.

1.4.1 Volumetric Analysis.

1.4.2 Gravimetric Analysis.

1.4.3 Optical Methods.

1.4.4 Separation Methods.

1.4.5 Electrical Methods.

1.5 Selecting an analytical Methods.

1.6 Methods & Cleanliness.

1.7 Laboratroy Note Books.

1.8 Safety in the Analytical Laboratory.

1.9 Laboratory operations & practices.

1.9.1 Filtration.

1.9.2 Drying

1.9.3 Measuring Volume

1.9.4 Graphs.

1.9.5 Concentration.

1.9.6 Percentage Solute.

1.9.7 Activity.

1.9.8 Standards.

1.9.9 Sampling.

1.9.10 Drying

1.9.11 Weighting

1.9.12 Precipitation

1.10 Analytical Balance .

1.10.1 Technique of weighing.

1.10.2 Weighing Errors.

1.10.3 Electronic Balance.

1.11 Cleaning and Calibration of Glassware.

1.11.1 Leaning of Glassware.

1.11.2 Calibration of Glassware.

1.12 Selecting and Handling of Reagents.

1.13 Sample Preparations.

1.13.1 Dissolution and Decomposition.

1.13.1 (a) Decomposing samples with Inorganic acid in

open vessels.

(b) Microware Decomposition.

(c) Combustion our an open flams dry ashing.

(d) Procedure of fusion.

UNIT-I

ANALYTICAL CHEMISTRY

1.0 Introduction

Chemistry could be divided into five main areas analytical, biochemical

inorganic, organic and physical. The analytical chemistry it is necessary for growth

and development of science and technology and it must be integrated with other

scientific and chemical disciplines.

1.1 Objectives

Analytical chemistry may be defined as the science and art of determining the

composition of materials in terms of the elements or compounds contained in them.

Analytical chemistry is the science of chemical identification and determination of the

composition of substances and materials their chemical structure, analytical aim can

be achieved, analytical methods can be divided into identification or detection

methods, methods for measuring the content of an element in a sample and

methods of determining the molecules composition of materials.

1.2 Analytical chemistry and its Role

Analytical chemistry is concerned with the chemical characterization of the

matter. It plays a imp. role in nearly all aspects of chemistry, for ex.-clinical,

agricultural, environmental, forensic, manufacturing, metallurgical, and

pharmaceutical concerns.Food must be analysed for contaminants (eg: pesticide

residence) and for essential (eg: vitamin) contents.

The quality of manufactured products often depends upon proper chemical

proportions and measurement of the constituents is a necessary part of quality

control.

The above description of analytical chemistry provides an overview of the

discipline of analytical chemistry.

An analytical chemist tries to serve the needs of many fields.

(1) In medicine, analytical chemistry is the basis of clinical laboratory tests which

help physicians to diagnose diseases and chart progress in recovery.

(2) In industry, analytical chemistry provides the means of testing raw materials

and for assuring the quality of finished product whose chemical composition is

critical.

(3) Environmental quality is often evaluated by testing for suspected

contaminants using the techniques of analytical chemistry.

(4) The nutritional value of food is determined by chemical analysis for major

components and trace components such as vitamins and minerals.

(5) An analytical chemist also makes imp. contribution to fields as diverse as

forensics, archaeology and space science.

1.3 Classification of Analytical Methods - Classical and

Instrumental Methods

The goal of a chemical analysis is to provide information about the

composition of a sample of matter. Modern analytical chemistry has at its disposal a

multitude of the most diverse methods and techniques of analysis for conducting

quantitative determination. Their classification is based on different principles, but

most frequently they are divided into two large classes (i) classical methods (ii)

Instrumental methods.

1.3.1 Classical Methods

These methods generally involved measurement of mass of a substance or

the volume of resulting solution.

These are also called chemical methods and according to quantity measured,

are classified as gravimetric and volumetric methods.

(i) Gravimetric Chemical Methods

These methods depend on the conversion of the substance concerned to a

reaction, product and an accurate determination of its mass.

(ii) Volumetric or Titrimetric Analysis

It is related to the measurement of the volume of reagent of exactly known

concentration used up in the titration.

In this method, the equivalence point, the moment when the amount of

standard solution added is equivalent to that of the substance being

determined, should be detected correctly.

Volumetric analysis include a wide variety of the types of chemical reactions

such as neutralization reaction, oxidation - reduction, precipitation reaction

and complex formation reactions.

A direct titration is a more frequent technique where an unknown solution

is titrated directly with a standard solution and the desired constituent is

determined by measuring the volume of the standard solution required to

react completely with the constituent.

Back titration is used when no indicator is suitable for a titration or the

reaction is slow and does not involve a sharp change in concentration at the

equivalence point. In these titration two standard solutions are employed.

Indirect method of titration are used when the substance to be determined

does not react directly with standardised solution or reacts with it in a non-

equivalent amount. In this method, the substance under titration, with the

help of auxillary reagent, is converted into an another compound, which is

titrated with the standard solution. eg. in the titration of K2Cr2O7 with

Na2S2O3, the K2Cr2O7 is first titrated with excess KI, as a result of which I2

evolved in an amount equivalent to the K2Cr2O7 content, is titrated with

Na2S2O3 standard solution using starch as an indictor.

OHICrHIOCr 22

32

72 732146

IOSOSI 6363 2

64

2

222

1.3.2 Instrumental Methods

The methods which involved the measurement of a physical parameter of the

system which is functionally related to the amount of the component being

determined are called instrument methods.

These further can be

(i) Physicochemical Methods

(ii) Physical Methods

(i) Physicochemical Methods

These methods are concerned with the measurement of certain physical

parameters of a chemical system that are dependable on the nature of the system

components and vary in the process of the reaction. The parameters include:

(a) Potential value in potentiometry, and (b) optical densities of coloured

complexes in spectrophotometry etc.

Physicochemical methods may be direct or indirect, depending on the

procedure of the determination. In direct methods, a substance is determined

directly by measuring some property of a system. In indirect methods, a

change in a property is used for detecting the end point of a chemical

reaction, i.e., it serves as a peculiar sensitive indicator.

The classification of physical and physicochemical methods generally depends

upon the character of the measured properties of the system. These methods

are generally classified into two broad groups : spectral (optical) and

electrochemical methods.

The optical methods are based on the relation between optical properties of a

system and its composition. The electrochemical methods are based on the

interdependence of electrochemical properties and composition of the system.

In addition to these groups, radiometric, mass spectral number is fast

growing day by day.

(ii) Physical Methods

These methods do not use chemical reactions. The composition of a

substance is determined by measuring characteristic physical properties of material

such as density, viscosity, surface tension of solution etc. or its components.

Spectral analysis is one of the most widely used physical methods of analysis.

Physical properties are of two types, namely, specific and non-specific. A

direct measurement is however, possible if the measured property is specific

for the substance being measured. If no specific property is available, the

measurement of two or more non specific properties may allow correction for

interfering substances.

1.3.3 Advantages of Instrumental Methods

These methods may be used by the analytical chemist to save time, to avoid

chemical separations or to obtain increased accuracy. The time saving features can

be realized in routine analysis, or where a considerable number of determinations

are to be made. The accuracy of some of the instrumental methods depends upon

the accuracy with which the classical or wet chemical analysis can be made. In other

words, we can say that an improvement in the classical methods of analysis will

mean further improvement in the accuracy of instrumental methods of analysis.

Table-1

Properties and Methods based on them

Physical property measured Analytical methods based on

measurement of property

1. Mass Gravimetric.

2. Volume Volumetric.

3. Electrical potential, electrical

conductance, electrical current,

quantity of electricity etc.

Conductometry, potentiometry

voltammetry, chronopotentiometry,

polarography, amperometry and

coulometry, (electrometric or

electroanalytical methods).

4. Absorption of radiation Spectrophotometry (X-ray, UV,

Visible, IR, colorimetry, atomic

absorption, nuclear magnetic

resonance and electron spin

resonance).

5. Emission of radiation Emission spectroscopy, flame

photometery, fluorescence,

radiochemical methods

6. Scattering of radiation Turbidimetry, nephelometry. Raman

Specroscopy

7. Refraction of radiation Refractometry, interferometry

8. Rotationof radiation Polarimetry, interferometry

9. Diffraction of radiation X-ray electron diffraction methods

10. Mass to chare ratio Mass spectrometry

11. Thermal properties Thermal conductivity and enthalpy

methods

1.4 Types of Instrumental Analysis

Following techniques are used in analytical chemistry

1. Volumetric analysis

2. Gravimetric analysis

3. Optical methods

4. Separation methods

5. Electrical methods

1.4.1 Volumetric Analysis

In these methods measurements are made in volume. In this techniques a

gas volume is measured or a volume of a titrant is measured. The procedures in

which volume of a titrant is measured is called a titration. In a titration, a solution of

known concentration is prepared as one of the reactants and it is known as the

titrant. It is then titrated against the sample solution or unknown solution using a

suitable indicator for detecting the end point at which the stoichimetric reaction

between the titrant and the sample is complete. From the volume of the sample

solution needed for a known volume of titrant of known concentration (standard

solution), the amount of the reactant in the sample can be calculated. Volumetric

titration are of four types and each type depends type of reaction.

For example, acid base titration involve a neutralization reaction. Thus acids

are determined by titration or neutralization with a standard base solution and

based by titration with a standard acid solution. For example,

H+ + Cl- + Na+ + OH+ + Na+ + Cl- + H2O

In oxidation reduction titration, a change in oxidation state of the

substances and the titrant is involved. For example,

6Fe2+ + Cr2O2-

7 + 14H+ 6Fe3+ + 2Cr3+ + 7H2O

In precipitation titrations, a stoichiometric amount of titrant as-

precipitating agent is added and volume required for the complete reaction is

measured. The amount of desired constituent is then calculated because the

precipitating agent is used as standard solution.

Ag+ + NO-3 + H+ + Cl- AgCl +H+ + NO-

3

In complexometric titrations, a complex is formed by adding the titrant (a

complexing agent) to the sample solution. For example, titration of Cu (II)

with EDTA.

HO2CCH2 CH2CO2H

Cu2+ + N - CH2 - CH2–N

Na+O-2CCH2 CH2CO-

2Na+

Cu EDTA + 2Na+ + 2H+

Ethylenediaminetetraacetic acid disodium salt (EDTA)

It should be noted that all complexing agents can be used as titrants in

complexometric titrations.

1.4.2 Gravimetric Analysis

It involves the separation of a substance from the solution of the weighed

sample into a pure weighable form of a stable compound of known percentage

composition. This analysis may be carried out by precipitation electrodeposition and

volatilization.

Gravimetric analysis by precipitation is the chemical analysis in which the

constituents of the substances in solution are determined by the

measurement of weight of the corresponding precipitate. The various

operations in obtaining a pure sample by precipitation are:

(1) Precipitation of the desired constituent

(2) Filtration

(3) Drying

(4) Weight of the precipitation

In electrodeposition, the desired constituent is deposited or isolated at an

electrode by the passage of an electric current. The weight of the desired

constituent is then calculated by the difference in weight of the electrode

before and after the Electrodeposition.

In volatilization, the sample is decomposed by a known stoichiometric

reaction in which one of the products is volatilized. The amount of vapourized

constituent is then calculated by the difference in weight before and after

volatilization. In this respect the process is similar to the electrodeposition

method.

1.4.3 Optical Methods

Optical methods are based on how the sample acts towards electromagnetic

radiation. The most important optical properties which can be co-related with

concentration are:

(1) The absorption or emission of radiant energy.

(2) The bending of radiant energy.

(3) The scattering of radiant energy.

(4) The delayed emission of radiant energy.

These measurements are made making use of instruments which involve the

use of lenses, mirrors, prisms and gratings. There are some other instruments

which are included in this general classification but do not have optical parts

and still depend on electromagnetic radiation. The most important techniques

are nuclear magnetic resonance, electron spin resonance and mass

spectrometry.

1.4.4 Separation Methods

Separations are necessary to simplify the sample by removing the

interferences prior to the final measurement. However, separation is not only

associated with interference removal. Qualitative or Quantitative separation of

components of a mixture is useful for purification or needed for concentration one or

all the components. Separation methods are used in many industrial processes of

isolating metals, organic compounds and other metals.

1.4.5 Electrical Methods

Electrical methods involve electronic instruments that are used to measure or

produce electrical phenomena. Current flow as a function of time, potential

developed or required, ability to pass a current and resistance, etc., are the

important properties which are related to the reaction taking place or/are causing a

reaction to take place. The fundamental measurements then are resistance, current,

potential and time.

1.5 Selecting an Analytical Method

It is an imp. task for the analyst to select the best procedure for a given

determination. This will require careful consideration of the following features :-

(1) The type of analysis required : - elemental or moleculal, routine or occasional.

(2) Problems arising from the nature of the material to be investigated eg:

radioactive substances, corrosive substances, substances affected by water.

(3) The concn. range which needs to be investigated.

(4) The accuracy required.

(5) The facilities available.

(6) The time required to complete the analysis, this will be particularly relevant

when the analytical results are required quickly for the control of a

manufacturing process. This may mean that accuracy has to be a secondary

rather than a primary consideration as it may require the use of expensive

instrumentation.

(7) The number of analyses of similar type which have to be performed.

(8) Nature of the specimen.

(9) Magnitude of the sample available.

(10) Kind of information sought.

1.6 Methods & Cleanliness

For an analyst it is very imp. to be aware of the procedures, handling of

instruments and basic techniques of analytical operations.

(1) The bench must be kept clean and a bench-cloth must be available so that

any spillage of solid or liquid chemicals can be removed immediately.

(2) The container vessels or bottles must be labeled, so that the contents can be

readily identified.

(3) To prevent contamination of the contents by dust, air and moisture, the

vessels should be covered immediately after use.

(4) Bark corks should not be used to cover the vessels because they invariably

tend to shed some dust.

(5) Reagent bottles must never be allowed to accumulate on the bench, they

must be placed on the reagent shelves immediately after use.

(6) All determinations should be performed in duplicate.

(7) The graph paper a printout obtained from a printer of modern instrument,

should be attached to the observation page of the laboratory record book.

(8) It should be regarded as normal practice to perform a rough calculation to

confirm the right order of printed results.

(9) Safety procedure must be observed in the laboratory at all times.

(10) Poisonous chemicals must be handed very carefully.

(11) All laboratory workers should familiarize themselves with local safety

requirements.

(12) In some laboratories the wearing of safety spectacles and gloves must be

compulsory.

1.7 Laboratory Note Books

The laboratory note book is a record of the work of an analytical chemist. It is

the source for reports, publications and regulatory submission the note book is a

record of original ideas.

Same good rules are given below for a well-maintained note book.

(1) A hard covered note book of A-4 size must be used for recording

experimental observations as they are made.

(2) Never use loose leafs.

(3) Number the pages consecutively.

(4) Always records only in ink.

(5) Never tear out pages. If page is not used, put a line through the page.

(6) Each page should be dated and signed properly.

(7) Name of the project should be written on the people space.

(8) All the data should be recorded on the same day, when they are obtained.

(9) In a note book, a double page should be devoted to each determination, title

of which must be clearly indicated.

(10) The record must conclude with the calculation of the result of the analysis

and in this connection the equations & reactions involved in the determination

should be shown together.

(11) Finally, appropriate comments should be made upon the degree of the

accuracy and the precision achieved.

(12) The printout from the printer should be permanently attached to the

observations page of the laboratory note book.

(13) It should be regarded as a normal practice to perform a "rough" calculation to

confirm that the printed result is of the right order.

1.8 Safety in the Analytical Laboratory

The General safety rules in the analytical laboratory are given below:-

(1) In the laboratory always clean up split chemicals.

(2) Broken on chipped glassware should not be left on the bench a shelves.

(3) Chemical bottles and apparatus should be placed properly after use.

(4) One should neutralize the acid spills with sodium bicarbonate and alkali spills

with boric Acid.

(5) Mercury spills should be vacuumed up with a section flask or dusted with

sulphur powder.

(6) Analyst should clean up the mercury thoroughly becok mercury vapours from

five droplets are highly toxic.

(7) If required, one should wear protective glasses, while working n the

laboratory.

(8) A person working in a chemical laboratory should locate fire extinguishers,

exits, safety showers, eye foundations and fire blankets.

(9) Any dangerous or potentially dangerous laboratory situation should be

brought immediately to the notice of the laboratory supervisor.

(10) One should perform only the authorized experiments, and should not work

alone in the laboratory.

(11) When working with volatile chemicals, as when heating acids or when using

organic solvents, use the fume hood.

(12) One should use a safety shield, when working with potentially dangerous

reactants.

(13) Special care should be taken when working with organic solvents.

(14) Many chemicals are inflammable and many have been identified as acute or

chronic toxic substances frequently carcinogenic. Use rubber gloves when

possible and avoid breathing in fumes.

1.9 Laboratory Operations & Practices

For a quantitative analysis there are many laboratory operations and

techniques. These are described as follows.

1.9.1 Filtration

Filtration is the separating process of solid phase from the liquid phase which

is the in its contact solution. The filtering process use diff. types of filter support to

collect the solid such as:-

(A) Filter Papers :- Munktels (Swedish filter paper), Schull (German)

(B) Crucibles :- Gooch crucibles, Aluminum Gucibles, Silica Gucible.

(c) Filter pulp Mats

(d) Asbestos

(e) Filter Membranes

1.9.2 Drying

For drying purpose desicator is used. It allows to cool the hot crucible in a

dry atmosphere, before desicator provides a dry and moisture free atmosphere for

storing a sample.

1.9.3 Measuring Volume

In analytical chemistry solutions are measured by graduated glass wares such

as volumetric flaks, pipette, burette etc. People handling and use of glass wares in

volumetric analysis needs an accurate reading of the liquid a solution level.

1.9.4 Graphs

In analytical chemistry, the experimental observations are analysed and

measured by calibration and titration curves.

1.9.5 Concentration

In stoichionetry reactions, concn is generally defined in terms of

(i) Molarity

) ( ltinsolutionofVolune

MolesM

(ii) Formality

SolutionofLitre

weightformulaGramF

(iii) Normality

SolutionofLitre

weighteGramN

quivalent

1.9.6 Percentage Solute

The percentage of solute may be defined as percentage by weight or

percentage by volume. When percentage solute is expressed as percentage by

weight, it means the parts of the total solution weight that is participated by the

solute.

1.9.7 Activity

Ideal concentration like normality molarity, or formality, corresponds to what

was originally added and true or effective concn. which makes into account the

various interaction, is called the activity.

a = c

1.9.8 Standards

For all types of determent of a standard or references point is necessary.

Standard

Primary Standard Secondary Standard

In chemistry, a substances where purity has been analysed may be primary

standard substances.

1.9.9 Sampling

Sampling is an imp. operation to analyse a material or substance. It is a

difficult task to get a proper and homogeneous sample. A lot of time and efforts will

be involved in the analysis of an improper sample. Sampling is of two types.

(a) Statistical Sampling

(b) Random Sampling

1.9.10 Drying

After getting the sample, it is imp. to know whether sample was to be used as

such, or it has to be dried. Some samples are hygroscopic in nature a may contain

moisture. Hence there are 2 types :

(a) Received Basis

(b) Dried Basis

1.9.11 Weighing

Samples are weighted after the drying process. Generally are analytical

balance is used for employed in triplicate.

1.9.12 Precipitation

If the main goal is quantitative precipitation, the whole process is known as

gravimetry. In this procedure the measurement is weight or weight change.

(a) The sample being analysed is weighed accurately.

(b) The pH should be adjusted by using buffer solution.

(c) Precipitation is carried out in hot dil. solution.

(d) The ppt is then separated form the mother liquor by filtration.

1.10 Analytical Balance

Weighing is an integral part of almost any analysis, both for measuring the

sample and for preparing standard solutions.

Analytical balance gives the accurate measurement of mass i.e., it compares

an unknown mass to a known mass under the same gravitational force. A chemical

analyst really deals with mass rather than weight. For most analytical purposes a

balance with a maximum load of 100-200g and an ability to weigh an object to 0.1

is required.

1.10.1 Technique of Weighing

There are two general techniques to weigh a sample.

In first technique, the entire sample, placed in a weighing tube is weighted,

subsequently the weighing tube is taken out from the balance pan and

sample is transferred to another container with the help of a spatula. The

empty weighing tube is again weighted and the weighted of the sample is

determined by the difference between the two. This technique is known as

weighing by difference. This procedure can be repeated for additional sample.

In an another technique, the sample is directly weighed on the pan of the

balance and collected on a weighed paper or watch glass. Once the sample is

weighed, it is transferred to another vessel. (It is not advisable to keep the

removing sample until a desired weight is transferred)

1.10.2 Weighing Errors

While using an analytical balance, there are five main sources of errors. These

are :

(a) Static Errors

These can be imparted to the balance from the operator or from the objects

placed on the pan. Semimicro and microbalances of equal arm type are particularly

susceptible to this type of error.

(b) Defective Balance

Errors due to balance construction or operation of the weights are possible.

These errors are difficult to discover in single pan balance, where the working parts

are enclosed. Defects may also occur because of corrosion, chipped knife edges,

dust and magnetic damping errors.

(c) Temperature Effects

These may be caused by temperature gradient in the balance case, because

convection currents will be present due to temperature gradient. Small temperature

gradient may cause draft against the pan and lead to erroneous weights, while large

temperature gradient may cause the beam lengths to change because of expansion

and thus lead to an error. Hence hot objects should never be weighted and balance

should be protected from sources of heat or draft.

(d) Operative Errors

Occur as a result of carelessness and improper handling of the balance and

they can easily be corrected and controlled. For example.

(1) Spillage of chemicals may lead to etching of the pan or other parts of the

balance.

(2) Sudden jarring or adding or removing weights or the sample from the pan can

damage the knife edges in the balance.

(3) Misreading the weight scale, spilling of weighted samples, poor handling of

the object during weighing are also operative errors.

These kinds of errors may permanently affect the accuracy as well as

sensitivity of the balance.

In addition, volatile contaminents may also cause errors. For example:- H2O

or CO2 may be absorbed by the objects from the atmosphere during weighing. As a

result, object will change weight during weighing. Even containers holding the

sample is capable of this action.

Operative error may be minimized by placing the balance in a low humidity,

controlled temperature room or in a dry box. Sometimes a small amount of descant

is placed in the balance. It is also desirable to dry the sample in an oven before

weighing at a temperature that is high enough to remove water, but not high

enough to cause sample decomposition. Before weighing the sample and its

container are cooled to room-temperature in desiccator.

(e) Buoyancy Effects

Buoyancy effects arise when an object is placed on the balance pan, the net

downward forces on the pan is due to the mass of the object minus the force due to

the buoyancy of air on the object. At balance.

m0 = mw + (Buoyancyo - Buoyancyw)

1.10.3 Electronic Balance

Modern electronic balances offer convenience in weighing and are subject to

fewer errors, a mechanical failure, than the mechanical balances.

(1) There are no weight or knife edges as in mechanical balances.

(2) In this, pan sits on the arm of a movable hanger & this movable system is

compensated by a constant, electromagnetic force.

(3) The position of the hanger is monitored by an electrical position scanner

which brings the weighing system back to the zero position.

(4) The compensation current is proportional to the weight placed on the pan

which appears as a digital display.

(5) These balances use the principle of electromagnetic force compensation.

(6) The balance is "zeroed" or calibrated, with a known weight.

(7) A single control bar is used to switch the balance on and off, to set the

display to zero, and to trace a container automatically on the pan.

(8) Electrochemical quartz balances are available with 100 g range that can

detect ng (10-9g) changes.

1.11 Cleaning and Calibration of Glassware

1.11.1 Cleaning of Glassware

Glassware must be perfectly clean & free from grease, other wise the

result will be inreliable.

Various methods are available for cleaning of glassware.

(1) Decon 90

Many commercial detergents are available which are suitable for this purpose.

eg: Decon '90' effective in moving contamination due to radioactive materials.

(2) Teepol

Teepol is relatively mild and inexpensive detergent which may be used for

cleaning glassware.

(3) CARE

A method which is frequently used, consists of filling up the apparatus with

"Chromic Acid Cleaning Mixture (CARE)", a nearly saturated solution of powered

sodium dichromate (or potassium dichromate) in concn sulphuric acid, and allowed

to stand for overnight. The acid is then poured off, the apparatus thoroughly rinsed

with distilled water and allowed to drain until dry.

(4) Mixture of Sulphuric Acid Nitric Acid

This may be used when the vessel is very greasy & dirty.

1.11.2 Calibration of Glassware

The calibration procedure involves determination of the weight of water

contained or delivered by the particulars piece of apparatus. The temp. of water is

observed, and from the known density of water at that temp, the volume of water

can be calculated.

In all calibration operations, apparatus to be calibrated must be carefully

cleaned and allowed to stand adjacent to the balance which is to be used together

with the supply of distilled deionized water, so that they acquire the temp. of the

room.

Graduated Flask

In the clean dry flask a small filter funnel is inserted into the neck and distill

water is added slowly. The funnel is then removed and then using a dropping tube

later is added dropwise until the meniscus stands on the graduation mark. Now the

flask is weighted and the temperature of water is noted.

Pipette

The pipette is filled with distilled water above the mark. Remove the excess of

water the pipette is then allowed to discharge into a clean weighted stopped flask.

The receiving flask is weighted & the temp. of the water is noted.

Burette

The calibration of a burette is similar to the procedure for a pipette, except

that several volumes will be delivered.

To calibrate a burette, first make satisfaction about its (i) leakage and (b)

delivery time.

1.12 Selecting and Handling of Reagents

The purest reagents should be used for quantitative analysis, the analytical

reagent (AR) quality is generally employed.

While handling the reagents following points should be kept in mind.

(1) Liquid reagents should be poured from the bottle, a pipette should never be

inserted into the reagent bottle.

(2) Particular care should be taken to avoid contamination of the stopper of the

reagent bottle. When a liquid is poured from a bottle, the stopper should

never be placed on the shelf or on the working bench.

(3) All reagent bottles should be kept scrupulously clean particularly ground of

the neck on mouth of the bottle.

(4) It there is any doubt about the purity of the reagents used, they should be

tested by standard methods for the impurities, which right the cause of errors

in the determination.

(5) Reagents which are used in analytical laboratory should be of analytical

reagent grade.

(6) Special grades to solvents for special purpose should be used e.g., spectral

grades or chromatographic grades.

(7) Whenever possible, pick the smallest bottle that will supply the desired

quantity.

(8) Unless specifically directed, never return any excess reagent to a bottle.

(9) Unless directed otherwise, never insert spatulas, spoons or knives into a

bottle that contains a solid chemical.

(10) Keep the reagent shelf and the laboratory balance clean & neat clean up spills

immediately, even though some are waiting to use the same chemical or

reagent.

(11) Observe local regulations concerning the disposal of surplus reagent and

solutions.

1.13 SAMPLE PREPARATIONS

1.13.1 Dissolution and Decomposition

Most of the analytical determinations are performed in aqueous solutions

of the analytic.

It is very difficult to select a people reagent and technique for decomposing

and dissolving an analytical sample particularly when refractory substance is involved

or the sample is present in trace quantity.

There are four types of common methods of decomposing & dissolving an

analytical sample.

(1) Heating with aqueous strong acids or bases in open vessel.

(2) Microwave heating with acids.

(3) High temp ignition in air or oxygen.

(4) Fusion in molten salt media.

1.13.2(a) Decomposing Samples with Inorganic Acids in Open Vessels

The mineral acids are generally used to decompose the inorganic samples in

open vessel. Usually, a suspension of the inorganic sample is prepared in the mineral

acid and then it is heated by flame or a hot plate until the dissolution is confirmed to

be complete by the total disappearance of a solid phase.

In this process the temp of decomposition is adjusted at the boiling point of

the used acid reagents.

The following acids can be used for this purpose

(a) HCl (b) HNO3 (c) H2SO4 (d) Perchloric Acid

(e) Oxidising mixture of acids (f) Hydrofluoric acid

(b) Microwave Decomposition

Microwave decomposition can be carried out in both closed vessels because

higher pressure and temperature can be achieved in them. The decomposition of

compounds in microwave oven is very fast and speedy, even in case of typical and

difficult samples it takes only.

5 to 10 minutes. In contrast, the same results require several hours when

sample is heated over a flame or a hot plate.

(c) Combustion over an Open Flame (Dry Ashing)

To determine the cations of an organic sample, it has to be heated till red hot

in an open dish or crucible once a flame so that all the carbonaceous matter gets

oxidized and converted into volatile components follows dissolution of the residual

solid. In addition, voltaic metallic compounds may be lost during the ignition

process. Although dry ashing is the simplest method of decomposing organic

compounds, it is often the least reliable.

(d) Procedure of Fusion

(1) Firstly, the sample is prepared by grinding and fine power is obtained.

(2) Mixing of flux and sample is carried out in a crucible.

(3) After fusion, the formation of a clear melt indicates the completion of

decomposition.

(4) The mass is allowed to cool, before solidification.

QUESTIONS

1. What is analytical chemistry ? Classify the analytical methods and describe the

factors affecting the choice and selection of an analytical.

2. What are the important points to remember before cleaning an analytical

laboratory?

3. How will you differentiate between:

(a) Classical and instrumental method

(b) Electronic balance and single-pan balance

(c) Parts per thousand and parts per million

(d) Stoichiometric and non-stoichiometric

(e) Normality and Formality

(f) Molarity and Normality

(g) Wet ashing and dry ashing

4. Write a short essay on laboratory operations techniques.

5. Write short notes on the following:

(a) Laboratory note book

(b) Analytical balance

(c) Semi-micro and micro balance

(d) Cleanliness and neatness in laboratory

(e) Selecting and handling of reagents

BLOCK-I

UNIT-II

ERRORS AND EVALUATION

Definition of terms in mean and median. Precision standard deviation, relative

standard deviation. Accuracy-absolute error, relative error. Types of error in

experimental data-determinate (systematic), indeterminate (or random) and gross.

Sources of errors and the effects upon the analytical results. Methods for reporting

analytical data. Statistical evaluation of data-indeterminate errors. The use of

statistics.

UNIT-II

ERRORS AND EVALUATION

2.0 Introduction.

2.1 objectives.

2.2 Mean.

2.3 Median.

2.4 Precision.

2.4.1 Standard Deviation.

2.4.2 Variance.

2.4.3 Co-Efficient of Variation.

2.5 Accuracy.

2.5.1 Absolute Error.

2.5.2 Relative Errors.

2.6 Types of Errors.

2.6.1 Determinate Errors.

2.6.2 Indeterminate or random Errors.

2.6.3 Gross errors.

2.7 Reporting of Analytical Data.

2.8 Statistical Evaluation of Data.

2.9 The uses of Statistics.

UNIT-II

ERRORS AND EVALUATION

2.0 Introduction

When numerical data and numerical result are measured with the greatest

Exactness that the instrument method and observer are capable of, it has been

observed that the results of successive determination differ among themselves to a

great or lesser extent. The average value of a series of measurements is accepted as

the most probable value.

2.1 Objectives

In all method the reliability of the result depends upon the magnitude of the

difference between the average value and the true value. In some cases difference

may be small, and in others it may be so large that the result is unacceptable. All the

measurement from the true value. The average value of these observations is then

considered to be the most probable value. The difference a between most probable

value and the true mean value the absolute error. The absolute error in the

measurement may be beyond the permissible limits and the probable average value.

2.2 Mean

Mean (Arithmetic Mean of ungrouped data) x1,x2,x3 …..xn, are n values of a

variable x1 then the arithmetic mean or simply the mean of there value is denoted

by x is defined as. The arithmetic mean of a set of observation is equal to their sum

divided by he total number of observations.

Ex.

If the mean of 6, 7, 4, and 10 is 8. Find the value of .

5

107468

, 40=27+

13 =

Arithmetic Mean of grouped Data. In a discrete frequency distribution the

arithmetic mean may be computed by the any one of the following methods.

(1) Direct Method

(2) Shortcut Method

(3) Step Diviation Method

Here, we shall study the computational arithmetic mean by direct method

only.

Direct Method

N

xfX ii , i =1 and N = fi =f1+f2+f3 …..fn

Ex.

Find the mean of the following distribution.

8

15

710

109

105f

64x

Soln

Calculate the Arithmetic Mean

xi fi fixi

4 5 20

6 10 60

9 10 90

10 7 70

15 8 120

N=fi=40 N=fi=360

940

360

i

ii

f

xfxMean

2.3 Median

The median is the middle result when replicate data are arranged according

to increasing or decreasing. For on odd no. of result the median can be evaluated

directly. For an even number, the mean of the middle pair is used.

Median of an ungrouped Data

It the values xi in the raw data are arranged in order of increasing or

decreasing magnitude then the middle most value in the arrangement is called the

median.

2.4 Precision

The precision the responsibility of the result accuracy without precision is

impossible.

Precision describe the reproducibility of measurement in their words the

closeness of results that have been obtained in exactly the same way. Three terms

are used to describe precision.

(i) Standard deviation

(ii) Variance

(iii) Co-efficient of variance

2.4.1 Standard Deviation

Standard deviation has been found to be more reliable than the near

deviation or relative mean deviation. The standard deviation of single measurement

can be obtained by extracting the square root of quotient obtained by dividing the

sum of the square of the individual deviations of the no of measurement made.

n

xi

2)(

xi = (Mn-M)

Mn = No. of observation

M = Mean

n = Number of measurements.

When the no. of determinations is small.

)1(

)( 2

n

xs i

(n-1) is the No. of independent deviations. From the mean which arises prove

in determination.

2.4.2 Variance

The square of standard deviation is called varience. It is devoted by S2.

2.4.3 Co-efficient of Variation

The co-efficient of varience is an accurate measure of the precision.

%100

SCV

S = Standard deviation

= data set mean value.

Relative Standard Deviation

When standard deviation is devided by the mean value called relative

standard deviation.

x

Sdeviation Standard Relative

if the result is expressed in parts per thousand

pptx

spptinRSD 100

2.5 Accuracy

The accuracy indicate the closeness of the measurement to the true or

accepted value and is expressed by the errors. Accuracy is often more difficult to

determine because the true value is usually unknown.

Accuracy is expressed in terms of

(i) Absolute error

(ii) Relative error

2.5.1. Absolute Error

The absolute error E is the measurement of a quantity x which is given by

E=xi - xt

xt = true of accepted value

xi = individual value of x making up a set of m replicate

measurement

2.5.2. Relative Error

The percentage relative error is given by the expression

100

i

tir

x

xxE

Relative error can also be expressed in parts per thousand.

2.6 Types of Errors

(1) Determinate or Systematic or constant error's

(2) Indeterminate or random errors

(3) Groos errors

(4) Errors in measurements

(5) Other errors

2.6.1. Determinate Errors

These are the errors which can be avoided and whose Magnitude can be

determined and the measurements rejected. It affects to the same degree the

results of a series of determination. Clarification of Determinate errors. These are

clarified into following categories.

(a) Personal errors

(b) Operational errors

(c) Instrumental and reagent errors

(d) Methodic errors

(e) Additive and proportional errors

(a) Personal Errors

These are due to the factors for which the individual analyst is responsible

and are not connected with the method or procedure.

1. Some persons are unable to judge colour changes sharply in visual

titrations may result in a slight over stepping of the end point.

2. Mechanical loss of Material in various step of analysis.

3. Errors in reading a burette.

4. Improper washing of precipitate.

5. Insufficient cooling of crucible in weighing.

6. Using impure reagents.

7. Ignition of precipitate at incorrect termperature.

8. Allowing hygroscopic materials to absorb moisture before or during

weighing.

9. Failure to apply buoyancy correction when required.

10. Errors in calculations.

(b) Operational Errors

These errors are mostly physical in nature and occur when sound and proper

analytical technique is not followed e.g. non-representative sampling.

(c) Instrumental and Reagent Errors

Due to improper instruments and reagents.

(1) Faulty construction of balances.

(2) Use of improperly calibrated weights.

(3) Graduated glassware and other instruments.

(4) The attack of reagents upon glassware resulting in the

introduction of foreign materials.

(5) Valatilisation of platinum at very high temperatures.

(6) Use of reagents containing impurities.

(d) Methodic Errors

These originate form incompleteness of a reaction. In gravimetric analysis

errors may arise owning to appreciable solubility of precipitates, co-precipitation and

post-precipitation, decomposition or voltalisation of weighing forms on ignition and

precipitation of substances other than the intended ones. In titrimetric analysis error

may occurs owning to failure of reaction to proceed to completion.

(e) Additive and Proportional Errors

The absolute value of an additive error is independent of the amount of the

constituent present in the determinant. Loss in weight of a crucible in which a

precipitate is ignited and errors in weights are the well known examples of additive

errors.

2.6.2 Indeterminate Errors

These errors are accidental and quite intangible over which the analyst has

no control. These errors are revealed by the small differences in the successive

values of a measured quantity when the measurement are made by the same

analyst. Types

(a) Variation within determinate errors

(b) Erratic Errors

(a) Variation within Determinate Errors

These errors cannot be prevented from variation i.e. igniting a precipitate of

xl (OH)3 to constant weight, an analyst may obtain. Successive values which vary

without a definite trend. This variation could be due to varying amount of water in

the weighed residue to xl2O3.

(b) Erratic Errors

The analyst has no control over erratic errors weighing with a sensitive

balanced subjected to variation will show erratic errors.

(1) Small errors occur more frequently than large ones.

(2) Positive and Negative errors of the same numerical magnitude are

equally likely occur.

(3) Narrow packed curve with steep slope indicate a relatively high degree

of precision.

(4) X broad curve indicates a relatively lows degree of precision.

2.6.3. Gross Errors

The grass errors are due to carelessness of the analyst.

(1) Use of numerically incorrect conversion factors.

(2) Wrong selection of method.

(3) Unsuitable storage of samples.

2.7 Reporting of Analytical Data

In expressing an experimental data, the following points and rules should be

kept in mind :

(1) Eliminate all digits that are not significant. Never retain more than one

doubtful digit.

(2) Express only one uncertain figure. For example, a values which is

known to be between 25.5 ml and 25.7 ml should be written as

25.6 ml, but not as 25.60 ml.

(3) In rounding off quantities to the correct number of significant figures.

Last figure retained if the following figure is 5 or above. This is known

as rounding up. Thus the number 8.856 has been rounded up to 8.86.

If the last digit discarded is less than 5, leave the next digit

unchanged. This is called rounding down.

(4) In addition or Subtraction. There should be in each number only as

many significant figure as there are in the last accurately known

number.

(5) In multiplication or division, retain in each factor one or more

significant figures than contained in the factor having the largest

uncertainty. The percentage precision of a product or quotient can not

be greater than the percentage precision of the least precision factor

entering into the calculation. Thus the multiplication of 1.26 x 1.336 x

0.5834 x 25.8652 should be done using the valued 1.26 x 1.336 x

0.583 x 25.87 and the result should be expressed in three significant

figures.

(6) Computation involving a precision not greater than one fourth of 1%

should be made with a inch slide rule. Slide rule is a good method for

checking the calculations made by logarithms.

Relative error can also be expressed in parts per thousand.

2.8 Statistical Evaluation of Data

1. Defining a numerical interval around the mean of a set of replicate analytical

result within which the population mean can be expressed to lie with a certain

probability the interval is called as confidence interval.

2. Determining the No. of replicate measurement required to ensure that an

experimental means falls within a range certain range with a given leaves of

probability.

3. Estimating the probability that an experimental means and a true value or

two experimental means and different.

4. Determining at a given probability level within the precision of two sets of

measurement differs.

5. Comparing the mean of more than two earnest to determine weather

difference in mean is real or it is the result of random errors. This process is

known as analysis of variance.

6. Deciding with a certain probability weather an appointment outlive in a set of

replicate measurement is the result of a gross error and this care be rejected.

2.9 The Uses of Statistics

Statistics is an essoutiae tool for the analyst. The use of statistical methods

can prevent judgment being mode on the basis of limited information in addition

there is rapiding developing subject of cheneometries which may be broadly defined

as he application of Mathematical and statistical methods to design or to appomise

measurement procedure and to prove the chemical information by analyzing relevant

data.

QUESTIONS

1. Explain the difference between

(a) Determinate and indeterminate error

(b) Mean and Median

(c) Absolute error and relative error

(d) Random and systematic error

(e) Personal and proportional error.

2. What do you know about the terms precision and accuracy?

3. What is an error ? Describe different types of errors.

4. Name three types of systematic. Suggest some sources of random error in

measuring the width of a 3-m table with with a 1-m metal rule?

5. Define (a) Variance (b) Coefficient of variation (c) Relative standard

deviation?

BLOCK-I

UNIT-III

FOOD ANALYSIS

Moisture, ash, crude protein, fat, crude fibre, carbohydrates, calcium

potassium, sodium and phosphate. Food adulteration-common adulterants in food,

contamination of food stuffs. Microscopic examination of foods for adulterants.

Pesticide analysis in food products. Extraction and purification of sample. HPLC Gas

chromatography for organophosphates. Thin layer chromatography for identification

of chlorinated pesticides in food products.

UNIT-III

FOOD ANALYSIS

3.0 Introduction

3.1 Objectives

3.2 Moisture Analysis in Foods.

3.2.1 Form of water in Foods.

(a) Free Water.

(b) Absorbed water.

(c) Water of hydrogenation.

3.2.2 Procedure for Moisture Analysis.

(a) Drying Method.

(b) Oven Drying Method.

(c) Distilaltion Procedure for Spices and

condiments.

(d) Chemical Method for low moisture Foods.

(e) Determination of KFR water equivalence

(KF-Reg.)

(f) Coulmetric Tirtation.

(g) Physical Methods.

3.3 Ash Analysis

3.3.1 Ash Content in Foods

3.3.2 Methods for Ash Analysis

3.4 Analysis of Protein

3.4.1 Protein (Casein) Content in Milk.

3.4.2 Protein (Casein) Content in Butter.

3.4.3 Analysis of cruds Protein Content of food.

3.4.4 Ultra violet absorption Method.

3.4.5 Birret Method

3.5 Analysis of Fat

3.5.1 Discontineous Solvent Extraction Method.

3.5.2 Non Solvent Kit Extraction Method.

3.5.3 Detergent Method of Milk Fat.

3.5.4 Refractive Index Method

3.5.5 Instrumental Method.

3.6 Analysis of Cruds Febric

3.6.1 Gravimetric Method.

3.6.2 Chemical Methods for the Analysis of Fibre.

3.7 Analysis of Carbohydrates

3.7.1 Methods of Analysis.

3.7.2 Analysis of Reducing Sugars. (Before Inverse)

3.7.3 Analysis of Reducing Sugars. (After Inversion)

3.7.4 Physical Methods for the Analysis of Carbohydrats

Syrups.

3.7.5 Enzymetic Methods.

3.7.6 Modern Analytical Methods.

3.8 Determination of Calcium.

3.9 Analysis of Potassium By Flame Photometric Method.

3.10 Common Adulteration in foods.

3.10.1 Harmful Effects of food Adultrants.

3.11 Contamination of food stuffs.

3.11.1 Organisms Causing food contamination.

3.11.2 Food Spoilages above pH 4.5.

3.11.3 Food Spoilages below pH 4.5.

3.11.4 Miscellaneous Micro organisms causing food

contamination.

3.12 Microscopic Examination of food.

3.13 Analysis of organophosphats in food by HPLC.

3.14 Gas Chromatography for organophosphate in food.

3.15 Thin Layer Chromatography for chlorinated pesticides in

food.

UNIT-III

FOOD ANALYSIS

3.0 Introduction

Chemical analysis of food is done to determine be acceptability, nutritive

value equality, composition and authencity of the food products. Major steps in the

analysis included

(i) to select and prepare samples,

(ii) to perform the assay,

(iii) to calculate and interpret the data.

3.1 Objectives

The food materials contain organic as well as in organic constituents. The

organic compounds comprise carbohydrates, proteins, fats, oils, and

nitrogenous compounds. The food analysis involves the determination of

percentages of moistures, ash, crude fat or ether extract, crude protein,

sugars and crude fibers etc. all of these important of our life.

3.2 Moisture Analysis in Foods

(1) Moisture is used as a quality factor for Jams, filling, sugar syrups & it is a

quality factor in the preservation of food products.

(2) Reduced moisture is used for convenience in packing of concentrated milks

and fruit juice, liquid sugarcane sweetener.

(3) Moisture is an inexpressive filler.

3.2.1 Form of Water in Foods

(a) Free Water : Free water acts as the dispersing agent for caller and the

solvent for salts.

(b) Absorbed Water : This water is held slightly to protein or is occluded in all

walls or protoplasm.

(c) Water of hydration : This water is bound chemically i.e. lactose

monohydrate.

3.2.2 Procedures for Moisture Analysis

(a) Drying Method's

The dry matter that remain after moisture removal is referred to as total

solids. The food samples can be dried in forced draft oven, vaccum oven or

microwave oven etc.

(b) Oven Drying Methods

Samples is heated and the loss of weight is used to calculate the moisture

content of the sample. The moisture content value obtained is highly dependent on

the type of oven used, condition in the oven, time and temperatures of drying.

100

)/( %

samplewetofWeight

sampleinwaterofWeightwtwMoisture

100 t

ry t t )/( %

samplewetofw

sampledofwsamplewetofwwtwtMoisture

100 t

ry )/( Solids otal %

samplewetofw

sampledofwtwtwtT

(c) Distillation Procedure for Spices and Condiments

Direct and reflux distillation techniques involve Co-distilling the water in a

food sample with a high boiling point solvent that is immiscible in water. Measuring

the volume of water. Distillation methods casue less thermal decomposition of some

foods than oven drying at high temperature. Water in measured directly in the

distillation procedure but reading the meniscus of a receiving tube to determine the

volume of water is less accurate than a weight measurement.

(d) Chemical Method for Low Moisture Foods

Chemical methods are used for low moisture foods like dried fruits &

vegetables roasted coffee coils, fats, sugar or protein. The records involve reduction

of I2 by SO2 in the presence of water.

2H2O+SO2+I2 H2SO4+2HI

Titration procedure

Iodine and SO2 are added to the sample in a closed chamber protected from

atmospheric moisture. Excess of iodine can't react with H2O can be determined

visually.

The colour in red brown.

Karl Fischer Reagent (KFR) is added directly as the titrant if the water in the sample

is accessible. If water in the solid sample is in accessible to the reagent, the

moisture extracted from the food with Methanol. The Methanol extract is then

titrated with KFR.

Determination of KFR water Equivalence (KF Req.)

The KFReq. value represents the equivalent amount of water that reacts with

1 ml of KFR. The KFReq. can be established with pure water, a water-in-Methanol

standard or Sodium tartrate dehydrate.

Amolg

SOHOHMolNaCOHmLOmgHqKF

/ 08.230

10002./369)/( .Re 26442

2

KFR eq. = KFR water equivalence, S=wt of sodium titrate dehydrate (g) A=ml of

KFR required for titration of sodium tartrate dehydrate.

100Re

%

S

KsqKFcontentmoisture

Source of Error in the Karl Fisher titration method in :

1. Atmospheric moisture must not be allowed to infiltrate the reaction chamber.

2. Moisture adhered to the walls of glassware must of drived.

3. Owing to incomplete water extraction.

4. Certain food constituents may interfere.

(f) Coulmetric Titration

It is ideal for samples with very low levels of moisture, from 0.03% to ppm

levels. In this method, I2 which is electrolytically generated to titrate the water, is

determined by the current needed to generate the iodine.

(g) Physical Methods

(1) Electrical Method

(a) Dielectric Method : Moisture content in certain foods can be determined by

measuring the change in capacitance or resistance to an electric current

passed through a sample.

(b) Conductivity Method : The conductivity of an electric current increase with

the percentage of water in the sample.

(c) Hydrometry : The moisture content in salt brines, beverages and sugar

solutions can be calculated by measuring specific gravity or density by

pycnometer or hydrometers.

(d) Refractonetry's Moisture: In liquid sugar product and condensed milks

can be determined by using a baume hydrometer a refractometer, or by

gravimetric means.

anglerayrefractedof

anglerayincidentofn

sin

sin index, Refractive

3.3 Ash Analysis

Ash refers to the inorganic residues remaining after complete oxidation of

organic matter in a food stuff.

3.3.1 Ash Content in Foods

The ash content of most fresh food rarely exceed 5% while dried may

contain 11.6% ash (wet weight basis).

3.3.2 Methods for Ash Analysis

Sample Preparation

(i) Fat and Sugar Products : Animal products, species and syrups require

treatment prior to cashing because of high fat and moisture or high sugar

content (forming) result in loss of sample. Bean, Sugars and syrups need to

be evaporated to dryness.

(ii) Plant Materials: Plant materials are dried prior to grinding. The sample may

be used for multiple determination. Fresh stem and leaf tissues should be

dried in two stages to prevent afrifact lignin.

Dry Ashing

Principle

Dry ashing is incineration at high temperature (5500C) in muffle furnance.

Ashing time is reduced with microwaving. Water and volatiles are vaporised and

organic substances are burned in air to CO2 and oxides of N2. Elements such as Pb,

Fe, Se, Mg may partially volitilise.

Procedure

- Weight 5 to 10 g sample in a tared crucible

- Place crucible in muffle. Ignite at 550C for 12 to 18 hours.

- Open the door of muffle furnance carefully to avoid leasing ash that may be

fulfill.

- Quickly transfer the crucible to a desiccator for cooling and weigh it.

Calculation

tcoefficienmatterdrySampleofwt

crucibleofwttareashingafterwtbasisdryash

.

. ) ( %

2. Wet Ashing

Wet ashing or wet digestion is a procedure for dissolving minerals and

oxidizing substances with high fat content (meatsite) using oxidizing agents.

Procedure

- Add 1g of dried, powdered sample is placed in 150 ml Griffin beaber.

- Add 10 ml HNO3 and allow it to soak overnight.

- Add 3 ml of 60% HClO4 and heat upto 3500C until fronting stops and HNO3 is

almost evaporated.

- Continue boiling until per chloric reaction occurs. Place watch glass on beaker.

Sample should be colourless.

- Cool the beaker wash watch glass with minimum devonised water. Add 10 ml

50% HCl.

- Transfer to 50 ml volumetric flask and dilutes with deinoibled water.

- Wash the hood precautiausly after last sample.

Preparation for Iron and Analysis in a Meat

Boil 2g sample in 30 ml HNO3 at 3500C on host plate until 10 ml remain. Add

10 ml of 60% HClO4 and continue boiling until copious fumes occurs.

Advantages of Wet Ashing

- Minerals usually remain in solution.

- There is little or no loss form volatilization because of lower temperature.

- The oxidation time is short and requires a hot plate, food, tongs and safety

equipments.

Disadvantages

- Wet ashing requires constant operation attention.

- Corrosive reagents are necessary.

- Only a few samples can be handled at one time.

- Per chloric acid react with iron to form ferrous perchlorate.

3. Modified Dry-Wet Ash Oxidation

- Evaporate moist sample (25 to 50 ml) at 1000C over might or in a

microwave oven.

- Heat on a hot plate until smoking classes.

- Ash at 5250C for 3 hours.

- Coal and wet with devosed distilled water and 3 ml HNO3.

- Dry and incinerate at 5250C for 1 to 2 hours.

- Weight sample after cooling in desiccatar.

4. Low Temperature Plasma Ashing

Principle- Low temperature plasma ashing refers to a specific type of dry

ashing method whereby foods are oxidised in a partial vaccum by nascent oxygen

formed by radio frequencies electromagnetic field generator.

Instrumentation

The equipment consists of a glass system with a variable number of chamber

for sample that may be evacuated by a vaccum pump.

Procedure

The ground material is inserted into individual glass boats which separate

glass chamber. The chamber is sealed and a vaccum is applied. A small flow of O2 or

air is introduced into the system maintaining minimum vaccum. The frequency

generator is less than 14 MHZ and adjusted by the amount of wattage applied (30-

200 ks)to control undation.

Advantages

- There is less change of lasing trace elements by volatilization.

- The low temperature (1500C) used with plasma as hers keeps the microscopic and

crystalline structure unaltered.

Disadvantages

The major disadvantages are small sample capacity, expense of the equipment and

operator's time.

Other Ash Measurements

1. Soluble and Insoluble Ash in Water

Weigh the total ash

Add 10 ml distilled water, cover the crucible and heat to boil.

Filter on ashless filter paper and rinse with hot distilled water five to six times.

Dry and re-ash filter paper for 30 min.

Weigh and calculate as percent water-insoluble ash.

2. Ash Insoluble in Acid

This ash determination is used to measure surface contamination (silicates) of fruits,

vegetables, wheat, and rice coatings.

Add 25 ml of 10% HCl to total ash or water insoluble ash.

Boil for 5 min. filter on ashless filter paper and wash with hot distilled water.

Re-ash dried filter paper and residue for 30 minutes.

Weigh and calculate as percentage.

3.4 Analysis of Protein

Protein is a common ingredient of all food materials analysis of protein is

required to know.

Total protein content.

Amino acid composition.

Protein content during isolation and purification.

Non protein nitrogen

Nutritive value

3.4.1. Protein (Casein) Content in Milk

Milk protein (casein) can be separated from milk and analysed by the

following methods :

Procedure

Dilute 200 ml milk to one litre with distilled water in a 26 beaber.

Add 1g glacial acetic acid when a white precipitate settles down.

Decent off the aqueous layer and wash the precipitate with water.

Grind the precipitate with a little 0.1% NaOH solution to neutralise the acid.

Filter the resultant suspension through muslin clatn by pressing it hard.

Add it’s the filterate by adding glacial acetic acid so that the solution contains

0.1% of it.

Wash the precipitate obtained from decanted water neutralist with 0.1%

NaOH solution and filter.

Repeat the process of precipitation and washing.

Again filter the precipitate with alcohol and then with to remove fats.

3.4.2. Protein (Casein) Content in Butter

It can be calculated as ---------

Percentage of protein =

(Percentage of moisture+lactic acid+fat-100)

3.4.3. Analysis of Cruds Protein Content of Food

Kjeldahl Method

Sample Preparation- Solid foods are ground to pass a 20 mesh screen.

Sample should be homogenous.

Procedure

Add H2SO4 and catalyst (HgO, Cu3 in 3:1) for complete breakdown of organic

matter. During digestion, protein N is liberated to form NH4+ ions H2SO4 oxidises

organic matter and combines with ammonium formed carbon and hydrogen are

converted to CO2 and H2O.

42442 )()( Pr SONH

Catalys

SOHNotein

Neutralisation and distillation's Alkali containing sodium thiosulphate is added

to nutralise H2SO4. Sodium thiosulphate helps to release N from Hg which tends to

bind NH4+. The ammonia so formed is distilled into boric acid solution containing

indictors methylene blue and methyle red.

(NH4)2SO4 + 2NaOH 2NH3 + Na2SO4 + 2H2O.

NH3 + H3BO3 NH4+ + H2BO3

- (Boratic ion)

Titration Borate anion is titrated with standardized HCl.

H3BO3- + H+ H3BO3.

Calculations

Moles HCl = Moles NH3= Moles Ni

The sample and reagent blank should be run to subtract reagent N from the

sample N.

10014

%

Mole

g

sampleofg

volumeacidedConcentratNHClN

3.4 4. Ultra violet absorption Method

Principal

At 280mm due to tryptophan and tyrosine resides in proteins. Since the

content of tryptophan and tyrosine in each protein is constant the absorbance at

280mm could be used to estimate the concentrate of protein, using Beer's laws.

Procedure

Protein are solublised in alkali or Buffer. Absorbance of protein solution in read at

280nm again a reagent blank.

Absorbance, x=abc, where =absorptive, b= cell or white path length, c=

concentration.

Advantages

- method is used to determine protein content of milk and meat products.

- The method is rapid, sensitive non destructive and used widely in part-column

detection of protein.

Disadvantages

- has not been used widely in food systems.

- Nucleic acid also absorb at 280mm. The absorption 280mm/260mm ration or

pure protein and nucleic acids are 175 and 0.5. One can correct the

absorption of nucleic acids at 280mm is the ratio of 280/26mm is known.

3.4.5. Biuret Method

A violet purple colour is obtained when cupric ion are complied under alkaline

conditions. Absorbance of colour occurs at 540nm. Colour intensity is proportional to

the is proportional to the protein content of the sample.

Other methods protein can also be analysied by measuring the physio-

chemical properties of proteins by lowery method, ninhdrin method, turbidimetric

method idye binding method and Bradford method.

3.5 Analysis of Fat

Fats are esters of fatty acids with teracyleglycerols. An accurate analysis of

lipids in foods is important for nutritional labeling to determine whether the food

with the standard of identify and is uniform.

Methods

1. Solvent extraction methods.

2. Non-solvent wet extraction methods.

3. Refractive index method.

4. Instrumental method.

5. Calorimetric method.

6. Mojonnier Method for the analysis of milk fat.

3.5.1. Discontineous Solvent Extraction Methods

Principle fat is extracted with a mixture of ethyl ether and petrollium ether.

Extracted fat is dried to a constant weight and expressed as percent fat by weight.

Proportion of samples weight or measure the test portion of a homogenous milk

sample. If lumps of cream do not disperse, warm the sample 380C and cool the

warmed sample to 200C.

First Extraction

- Weight 10 g milk into a mojonnier fat extraction flask.

- Add 1.5 ml NH4OH and shake vigaroulsy. NH4OH neutralizes acidic and

dissolves protein.

- Add 10 ml of 93% ethanol to prevent gel formation and shake for 1 minutes.

- Add 25 ml ethyl ether to dissolve the lipid and shake well.

- Add 25 ml petroleum ether and shake. It remove moisture from the ethyl

ether extract and dissolves more nonpolar lipid.

- Centrifuge for 30s 600 rpm.

- Decant ether solution from the flaks into the previously wughed mojonner fat

disk.

Second Extraction

- Add 5 ml of 95% ethanol and shake vegarously for 15s.

- Add 15 ml ethyl ether and shake for 60s.

- Add 1 ml petroleum ether and shake for 60s.

- Centrifuge for 3s at 600 rpm.

- Decent solution into the same mojonneir disk.

Third Extraction

- Add 15ml ethyl ether and 15mL petroleum shake for 60S.

- Centrifuge for 30S at 600 rpm and decent solution into the same mojonnier

disk.

- Evaporatis the solvent in the disk on hot plate at 1000C in a food.

- Dry the disk and fat to a constant weight in a forud air oven at 1000C.

- Cool the disk to room temperature and weight.

Calculation

% Fat = 100 x [(wt. of disk+fat)] - [(wt. of disk)] - ( av wt. of blank reside)

(wt. of sample)

Mojonnier Method of Fat in Flour

- Mix 2 gm sample and 3 ml ethanol in a 50 ml beaker.

- Add 10 ml HCl heat the beaker at 800C in water bath with stirring for 30

minutes for hydrolysis.

- Add 10ml alcohol and cool. The acid hydrolysed flour is extracted by a

mixture of ethyl ether and petroleum ether as described in the Mojonnier

method for milk fat.

3.5.2. Non solvent wt Extraction Methods

Gerber Method for Milk Fats

Principles Sulphuric acid and anayl alcohol are added to a known volume of

milk H2SO4 digests proteins and carbohydrates, releases fat and generates heat.

Procedure

- Add 10 ml of H2SO4 at 200C into a Gerber milk battle.

- Accurate measure milk sample 11 ml into a Gerber bottle using a Gerber

pipette. Add issonyl alcohol.

- Heat the bottle in a water bath at 600C for 5 min. Read the fat content from

the graduations on the bottle neck.

Applications

Gerber method is simpler, faster and has wider application to a variety of

dairy products.

3.5.3. Detergent Method for Milk Fat

An anionic detergent, dioctyle sodium phosphate, is added to disperse the

protein layer to liberated fat. In case of other food products, a strong hydrophilic

nonionic polyoxy ethylene detergent, sorbitan monolauete is added to separate fat.

The percent fat is measured volumetrically and expressed as percent fat.

3.5.4. Refractive Index Method

The Refractive index is characteristics of each kind of fat and the values vary

with Degree and type of nusatcoation oxidation heat treatment temperature and fat

content.

3.5.5. Instrumental Methods

Infrared method for milk fat- infrared method is based on adsorption of

infrared energy by fat at a wave length of 5.73.The more the energy absorption at

5.73 the higher the fat content of the sample. This method is used to determine

the fat content.

3.6 ANALYSIS OF CRUDE FEBRIC

Dietary Fibre in defined as lignin plus plant poly sacchrides that cannot be

digested by human enzymes.

3.6.1 Gravimetric Methods

(i) Crude Fibre:- The crude fibre is analysed by sequential extraction of the

sample with 1.25% H2SO4 and 1.25%. NaOH. The insoluble residue is dried,

weight and head to correct for mineral contamination of the fibre residue.

(ii) Total, Insoluble and soluble fibre :- Ruplicate samples of try fact

extracted ground foods are enzymatically digested analysis dnyloglucosidare

and protease to remove starch and protein. Insoluble fibre is collected by

filtration. Soluble fibre is precipitated by adding 78% ethanol filtrate fibre -

Residue weight - (Weight of protein + dist) This (sos/method can be used to

determine fibre content of all foods.

3.6.2 Chemicals Methods for the Analysis of Fibre

Chemicals procedure collect macromolecules in the amylase amyloglu

cosidase digest by filtration with or without ethanol precipitation. The poly

saccharides in the precipatute are hydrolysed with H2SO4 and quantitated

calorimetrically or chromatographically (GC or HPLC).

Thander - Marlet Methods

Principle

Free Sugar and lipids are extracted with ethanol and hexane starch is

removed by enzymatic digestion and insoluble fibre is separated from soluble fibre.

Fibre protections are hydrolysed with H2SO4.

Procedure

1. Dry ground sample of food.

2. Sonicate and extract with ethanol and then hexane (2 times)

3. Filter between extraction with Whatman No. 65 paper.

4. Extracted residues are dried and weighed to determine Sugar and lipid loss.

5. Dry sample 4 to 59.

6. Digest starch with termamyl in 75 ml of 0.1 m acetate buffer, pH 5.0 with 70

ppm Ca2+ at 960C.

7. Digest starch with amyloglucarisdase for 16 hours.

8. Centrifuge and filter to separate soluble and insoluble fibre.

Filtrate

(a) Collect soluble polysachracides ppt with ethanol or by dialysing filtrate and

freeze-drying the diolysate.

(b) Hydrolyse soluble fibre with in H2SO4 (3h, 100%)

(c) Soluble fibre, amalyse sugar Uronic acids are anaylysed colorimetrically,

Neutral Sugars are measured by HPLC or GC.

Pellet and Filter Retentate

(a) Wash with ethanol, acetone and dry overnight under vaccum (400C)

(b) Hydrolyse cellulose with 12N H2SO4 (1hr)

(c) Dilute acid to 1N and hydroluse non cellulose insoluble polysaccharides for 3

hrs.

(d) Centrifuge and vaccum filter. Wash filter retentate with water.

3.7 ANALYSIS OF CARBOHYDRATES

Carbohydrates play an important role in human nutrition. Carbohydrtes

analysis of raw materials and processed foods can be used to provide a wealth of

information. The fingerprint oligosaccharide patterns can be used to detect food

adulteration.

3.7.1 Methods of Analysis

1. Chemicals methods for the analysis of Monosaccharides and oligasaccharides.

(i) Munson and Walker method for the analysis of reducing sugars

carbohydrates are oxidized on heating with an excess of cupric

sulphate and alkaline tartrate in basic medium to keep copper as

copper (Cu++) hydroxide.

- Upon heating, water is driven off and copper oxide is converted to cuprous

oxide.

- Cuprous oxide precipitates as the carbohydrates are oxidized and can be

determined by following methods.

(i) Gravimetric Method.

(ii) Electrolytic deposition from HNO3 where the copper oxide is

dissolved in HNO3 and then deposited on Pt electrodes. The weight gain

the electrode is related to the reducing Sugar content.

(iii) By titration with sodium thiosulphate Cuprous oxide is dissolved in

nitric acid. KI is added and the iodine is oxidized to I2.

(iv) By titration with KMno4 cuprous oxide is related with ferric sulphate

Fe3+ is reduced to Fe2+. Ferrous ion is then titrated with KMno4

resulting in a colour change.

Cu2O+Fe2(SO4)3 FeSO4+CuSO4+Cuo

Modified Munson and Kialber Method for the Analysis of Glucose

Fructose and Invert sugar is modified method involves to use of an excess of

alkaline copper Nitrate and Na2CO3. Following deduction, the excess copper Nitrate

is reacted with excess KI and the liberated I2 is titrated with sodium thiosulphate to

amalyse carbohydrates.

3.7.2. Analysis of Reducing Sugars (Before Inverse)

Take 1% reducing Sugar solution (e.g. honey) is aressed burette. Pipette

out accurately 5 ml of fehling solution A and 5 ml of fehling solution B into a 100 ml

conical flask and dilute it with 40mL of distilled water.

- Fehling solution A, Dissolve 69.278g CuSO4 in distilled water and dilute to

1000 ml.

- Fehling Solution B, Dissolve 346g of Rochelle salt and 200g of NaOH in

distilled water and dilute to 100ml.

- Heat the mixture of conical flask on hot plate.

- Run down 1% honey solution from the Burette into the mixture of conical

flask till the solution terms brick red in colour.

- Add 1mL of 0.2% methylene blue indicator solution.

- Again add honey solution till the end point is indicated by the colour change

from blue to red.

- Note the reading of the burette.

Calculation

Solutionnoney theof valueTitro

98.050solitor FehlingStrength Sugar Reducing Total

Calculation of Strength of Fehling Solution

Strength of Fehling solution is obtained by titration against 0.5% glucose (0.5

g in 100 ml of water) solution. If x ml of 0.5% glucose solution is required for

complete reduction of 10 ml of Fehling solution A and B .

10100

5.0Solution Fehling ofStrength

x

Conversion factor from glucose (mol. wt. 180) to starch (mol. wt 162).

10 parts of glucose are equal to 9 parts of starch.

9.010

9

180

162Starch toglucose from Conversion

3.7.3. Analysis of Reducing Sugars (After Inversion)

- Pipitte out 1 ml of 10% none (reducing Sugar) in 100ml conical flask.

- Add 2 ml glacial acetic acid and heat to bail keep it for 2 hours.

- Neturalise at with Na2CO3.

- Make up the solution to 100 ml with water in a measuring flask.

- Titrate this solution against 10 ml of Fehling solution A and B as done in

previous experiment.

Calculation

Solutionnoney theof Value Titrate

0.98 x 50 Solution x Fehling ofStrength inversion)(after Sugar Reducing

3.7.4. Physical Methods for the Analysis of Carbohydrate Syrups

Physical methods like polarimetry ,refractometry and specific gravity are

useful as rapid quality control techniques for pure carbohydrate syrups and juices.

3.7.5. Enzymatic Methods

(i) Total change method

Sufficient enzyme is added to convert av of the substrate in the food sample

to product. The amount of substrate in the sample is than determined from one total

change in the sample either as substrate disappearance or as product formation.

(ii) Rate as say per Kinetic Method

First the initial role of the enzyme substrate reaction is determined.From the

relation the concentration of enzyme, substrate, activator or inhibator may be

determined.

3.7.6. Modern Analytical Methods

(i) Modern Methods afford accurate analysis of structurally similar

carbohydrates at trace concentration.

(i) HPLC

(ii) Microscale HPCL

(iii) High performance capillary elecrophoresion.

(iv) Micullar performance capillarty chromatography.

(v) Capillary gas chromatography.

(vi) Supercritical fluid chromatography.

(vii) Mass and NMR spectroscopy.

3.8 Determination of Calcium

Reagent Required

- Dilute HCl 2 volumes of Conc. HCl dilutes with 5 volumes of water.

- NH4OH and saturated ammonium oxalate solution.

- Standard 0.1 KMno4 solution. Standardised against sodium oxalate.

- Dilute H2SO4 1 volume of Conc. H2SO4 diluted with 4 volumes of water.

- Acetic Acid volume of glacial acetic acid diluted with 2 volumes of water.

- Bromo cresol green indicator solution Grind 0.1g bromo 10 Cresol green with

14.3 mL of 0.01N NaOH is an agate mortor.

Procedure

- Weigh 2 to 4 g of the material and obtain its total ash.

- Digest the ash in dish with Dil. HCl Evaporates to tryness. Treat the residue

with dilute HCl and again evaporate to dryness on a water bath. Treat the

residue with 10 ml Conc. HCl add 30 ml of water and filter in a 250 ml

beaker.

- Wash to the residue with not water and collect the washing in the same

beaker.

- Add to the solution in the beaker 0.5 ml of bromocresol green indicator and

then NH4OH till the colour changes to blue.

- Filter the solution wash with hot water Called the washing in the same beaker

and heat to boil.

- Add Saturated ammonium oxalate solution dropwise till the precipitate

appears and then add excess solution heat to boil.

- Digest for 3 hours.

- Pour 20 ml of hot water on the precipate remaining on the filter paper by

washing with hot dilute HCl into the original beaker. Wash the filter paper

with hot water.

- Reprecipitate by adding NH4OH and a little ammonium oxalate solution.

- Digest for 3 hours filter. Through the some filter paper. Wash with hot water

until it is chloride free.

- Perforate the apix of the of the filter Con. Wash the filter paper with not

dilute H2SO4 and titrate with standard KMno4 solution at 700C.

Calculation

where8.2

massby percent CalciumM

NV

N = Normality of standard KMno4 solution

V = Volume (ml) of the standard KMno4 solution used for

titration.

M = Mass (g) of the material taken for the test analysis.

ashingfor taken sample ofKit x estimationfor taken Volume

100 x soleticash of Volume Total x 0.2 x Titremg/100g Ca

3.9 Analysis of Potassium By Flame Photometric Method

Principle

Potassium in solution is atomized into an oxyhydrogen flame. The flame

execitesatoms of potassium causing them to must radiation limited is measured on a

spectrophotometer.

Reagent

(1) KCl stock solution Dissolve 1.90 g of KCl in Distilled water and make up the

volume to 1 litre.

(2) Standard solutions measure 150 ml stock standard solution and 5ml HCl into a

flask and make solution to 1 litre. In order to compensate for minute

interferences caused by other ions in the determination of potassium. It is

necessary that the standard solution be augonented with equivalent

concentration of those ions that occurs in highest proportion in the sample

being analysed.

Standard Curve

Draw a allegation of standard solution from 0 to 150 ml atomise sitting the

top standard at 100% trasmittance. Note the luminosity of the flame for each

concentration. Draw a standard curve by plotting concentration on abscissa and the

percentage luminosity on the ordinate.

Procedure

Dilution aliquotes of ash solution so that it contains less than 150 ppm

potassium. Add HCl so that the concentration of acid is same as that in the standard

solution. Atomise the diluted extract in a calibrated flame photometer with the

wavelength dial set at 768 nm and transmittance set at 100% for the top standard

solution of potassium.

Calculations

1000 x Sample ofK Weight

100 dilution x x up made x volumeconce standard from found PPmKng/100g

3.10 Common Adulteration in Foods

Milk the addition of starch skimmed milk water of removal of fat.

- Milk powder Starch, Moisture, fat deficiency.

- Pure Ghee- Vanaspati Ghee, Animal Fat, Rancid Stuff, excess moisture.

- Vanaspati Ghee- Animal body fat, rancid fat, argemon oil, seami oil,

prohibited colours as well as flavour.

- Vegetable oils- Minerals oil, rancid oil, argemone oil, rubber seed oil, tea,

seed oil, watermelon seed oil.

- Butter- Animal fat, starch excess moisture, rancid stuff, Vanaspati ghee,

prohibited colours.

- Pulses- Massoor, gram,Khesari dal, sand dirt, coal tar dyes.

- Dal- Arhar Khesary dal, coloured with netainl yellow.

- Wheat flour- Atta, sujji, maida,sand dirt, soapstone, excess bram, chalk

powder.

- Mustard - Argenoa seed

- Common Salt- fine white sand, excess moisture excessive salt.

- Vinegar- mineral acid, coal tar dyes, Synthetic Vinegar sold as malt, or

wine, less amount of acetic acid.

- Ajwain- fine sand and foreign seed.

- Coriander- Cow dung, saw dust, house dung, powered bran, foreign starch,

- Chilles- Brick powder, coloured saws dust talcum powder, foreign starch,

powdered bran.

- Cardamon (Choti ilachi) Exhausted spices

- Cinnamon (Dalchini) - Canis bark.

- Garam Masala (powdered mixture of various species)

- Tealeaves - Saw dust.

- Coffee powder used coffee chicory roasted date seeds, tamarind husk starch

- Sweets, Metanil yellow.

- Ice Cream- Artificial sweetner, starch and no permitted colour.

- Soft drink - Prohibited colours, flavours ,sweetner, Saubarine, mineral acids,

bacterial and metal contamination.

- Processed foods - Prohibited food additive solvent residue and microbial

contamination.

- Ginnamon - Carnica burk.

3.10.1 Harmful Effect of Food Adultrants

(1) The consumption of adulterated foods has a slow pairing effect. The victims

of adiable oil adulterated with argemone oil show epidemic lepopsy.

(2) Mixture of turmeric powder with lead chromate causes lead poisoning,

anaemia and even abortion.

(3) An excessive intake of khesaridal in pulses causes permanent paralysis of

limb.

(4) The use of culture and non-permitted colours in dals, sweets or tea leaves.

(5) The consumption of meat from antibiotic fed animals causes multiple

structure resistance hardening of arteries and caronary heart disease.

(6) Gossypolain cotton said flour and panallidine in mushrooms causes cancer in

human.

3.11 Contamination of Food Stuffs

Under processing the failure to destroy all bacteria capable of subsequent

growth in the product during the heat process. Leakage is due to the contamination

of the product after an adequate heat process due to faulty seam or damage to the

can after sealing.

3.11.1 Organisms Causing Food Contamination

(1) Thermophilic group such as

(i) Flat sour

(ii) Thermophilic anaerobes

(iii) Sulphide spoilage microbes

(2) Mesophilic groups include

(i) Putrefractive anaerobes

(ii) Butyric anaerobes

(iii) Aciduric flat saws

(iv) Lactobacilli

(v) Yeasts

(vi) Moulds

3.11.2 Food Spoilages above pH 4.5

- Bacillus stero thermophilic cause flat saur spoilage in low acid foods (ph 5.3)

like peas corn, potatoes.

- Bacillus coagulants contaminate in medium acid (ph 4.6) canned products

such as corn, spinach asparagus.

- Mesophilic anaerobes including clostridium behefinura disintegrate solid food

products produce Odour, CO2, H2.

- Butyric acid anaerobes, Cl butyricum/ateterorate vegetables, Corns, soups

and sauces.

- Cocciymould and yeasts casue frothy permentation in liquars and brines due

to leakage.

3.11.3 Food Spoilage Below pH 4.5

- Bacillus Coagulants (B. thermoacidurans) causes occasional spoilage in

tomato juice dew to under processing.

- Moulds causes softening or disintlgration in canned fruits due to leakage of

containers.

- Cl. pasteurianum and Cl. butyricum, mesophilic obligate anaerobes spoil

pears, figs, pine apple due to spare forming anaerobes.

- B. polymyxa group (B. macerans) contaminate citrus juices, prunes jack fruit

and peach etc.

3.11.4 Miscellaneous Micro-Organisms Causing Food Contamination

- Zearalemone, an oestrogenic mycotoxin produced by Fusarium readily

colonise wheat, barely, rice, maize, cerals and bread.

- Listeria contaminate with dairy products (Chease, yoghurt, /meat and

vegetables).

- Dconynivalenol (DON or vemitoxin-) DON is related to compound known as

tirchathocens formed by fusarium graminearum and F. Culmorum.

- Aspergillus floves and A. parasiticus produce alfatoxine that damage a variety

of foods including nuts, dry fruits, cereals and herbs.

3.12 Microscopic Examination of Food

1. Plate Method

Adding enriched food samples to a micro titrate plate a highly specific

monoclonal antibody conjugate is added to it which finds to microbe antigens

forming an immune complex. The presence or absence of microbe is determined by

the addition of a colourless substrate which produces a coloured product in presence

of a particular micro-organism.

2. Coliform Count Method for Examining Fresh Fruits and Vegetables

Reagent required is ringer solution. It is used at one-quarter the original

strength, and is prepared by dissolving 2.15 g NaCl, 0.075 g KCl, 0.12 g CaCl2/

dry/and 0.5g Na2S2O3.5H2O in 1000 mL of Distilled water. Methods Shake 100 g of

the vegetables with 200 mL of Ringer solution. Allow it to sand for 20 min and

decant. Test positive tubes for the presence of coli.

3. Total Bacteria Count for Examination Frozen Fruits and Vegetables

Preparation of dextrose- Tryptone broth or Agar culture medium. The

ingredients are 10g tryptone, 5g dextrose, 0.04g bromo cresol purple 12g and 1 l

water. Steam the ingredients until dissolved.

Procedure

Add 1g of inoculum to the sterlises petridish and pour 10mL of melted agar

medium. The growth of organisms in the broth is indicated by the change of colour

from purple to yellow. The colonies appear on the surface with a typical spot in the

centre. Count total bacteria growing at 70C in 5 days also count lactic acid bacteria,

moulds and yeasts. Slime usually contains large number leuconostocs which gives

them a yellow appearances but sometimes heavy growth by coryneforms produces

ammonia and this neutralizes the acid formed by Luconostoc count on frozen

vegetables are low (106/g).

4. Microbial Count in Vegetables and Fruits

Culture and inoculate dextrose - tryptone agar, tomato juice and incubate at

300C aerobically and anaerobically.

Counts for lactic acid bacteria, flat sour thermophiles, mould, yeast and H2S

producing anaerobes.

In both carbonated and non-carbonated drinks the microbial counts dimisshed

in time.

In fruit juices, lactic acid and acetic acid bacteria may grow at pH4. Fruit

juices of oranges, lemon and grapes fruit used for soft drinks and beverages

must be sterile and give a negative result.

5. Direct Microscopic Examination of Food

Take the food content in a sterile container for subculturing. Make smears

with a sterile inoculating loop stain with methylene blue and gram stain. The

presence of gram positive rod suggests underprocessing while E. cocci and yeasts

etc.

Suggests Leakage Spoilage

Pesticides Analysis in food product chromatographic techniques used for the

analysis of pesticides in food stuffs are HPLC, GLC and TLC.

General Extraction and Purification of the Food Samples

Extract 20g of finally ground food sample with dichloromethane in the soxhlet

exractor for 3 hours. Transfer it to a Kudema Damish flask. If the cereals extract it

cloudy pass it through a column containing 20g of anhydrous Na2SO4 wash the

column with 40mL of lexane or isopropyl alcohol and mix the washing to extractor

before transferring it to the vaporator. Add

3 drops of liquid paraffin heat the contents on a steam bath until the volume

becomes 3 ml.

3.13 Analysis of Organophosphates in Food by HPLC

Organophasphate insectides present in food products may be parathion,

malathion, methyl paratnion, diazenon, tritnion etc.

Reagents

(i) H2SO4

(ii) Acetone

(iii) Hexane

(iv) Dichlaromethane

(v) Methanol as eluting solvent

Experimental Techniques

Extraction of the Food Sample

Extract the sample (10) in a separately funnel and evidety to pH with H2SO4.

Add 60 ml of acetone and shake. Then extract with 60 ml dichloromethane and

hexane (1:1) in the original sample container and organic phase is collected in

kudema Danish flask. Extraction is repeated twice with 50 ml each of dichlaro

methane and hexane and solvent is treated as a above. Solvent extract volume.

Then concentrates is injected to HPLC for the analysis of organophosphates.

Standard Conditions for Operating HPLC

The column of the HPCL is packed with 5m c-8 bonded phase particles.

The width and height dimension of column are 4.5 x 250 mm.

The flow rate of eluting solvent method is maintained of 2mL per minute.

A UV detector is attached to the instrument.

Process

The organophosphates are separated by using the gradients elution system of

mobile phase and the monitored the UV detector at 254mm chromatogram showing

the peaks of various. Organophosphates in food sample.

Calculations

Calculations are based on peak height measurement of the sample and the

standard for determing the concentration of species.

Analysis of Chlorinated Insecticides of Milk by HPLC

Automated HPLC pesticides analysea can be used for the analysis of

chlorinated insecticides in milk by injecting raw milk on to a shot slica precolumn

where the fat was retuned and the pesticides eluted with hexane. The less polar fat

eluting organo chlorines such as DPT, DDE, and -BHC stared at the top of a larger

analytical column.

3.14 Gas Chromatography for Organophosphates in Food

Organophosphates such as malathinon parathion, diazenon, chearthion meta-

systox in food stuffs can be analysed by gas chromatography.

Analytical Steps

Sample preparation

It involves chapping, grinding armacreating the food sample containing

argamophasphate.

Extraction and Purification

A 250g of the copper or macerated composite sample is blended with

acetonitirile aracetone.

Anhydrous salt (NaCl or Na2SO4) can be added to absorb water or water can

be added so that the crude extract can be purified with a subsequent

partitioning steps with an organic solvent.

Sometimes emulsion are formed. Emulsion formation can be minimized by

adding a small quantity of saturated salt solution or with a fews drops of

alcohol.

For matrices like Butter fats and animal tissue sufficient water is added to the

sample to obtain at total of 100g of water.

Acetonitrile (200ml) and dichlaromethane (150ml) or acetone (200ml) and

petroleum ether (150ml) are added to water amended sample together with

NaCl.

The mixture is blended at high speed for 2 min.

The dilution reconcentrations steps are repeated to ensure the complete

removal of those extraction solvents that can affect the operations of the

detector.

Standard Conditions for Operating Gas Chromatography

Capillary column pached column megabore column may be used. The column

of GC is packed with chronosurb WHp capilay GC columns are fabricated from

fused silica.

Active stationary phase is usually permanently bonded to the inner surface of

the column.

The temperature of the gas chromatograph kept at 2000C for 10 minutes the

temperature of the injector is maintained at 2250C.

N2 is used as carrier gas and its flow rate is maintained at 25ml per minutes.

Procedure for the Analysis

An autoinjector can deliver a present volume of sample to the

chromatograph.

Components partition between the stationary phase and a carrier gas

according to their relative affinities for the two phase.

Now a cilliary devices are used in automation gas chromatographs to increase

the degrade of automation of the separation, detection and quantitation of

chromatograms of pesticides in foods.

Micro computer based GC software packages can be used to compare test

chromatogram with a control of the same food matrix.

3.15 Thin Layer Chromatography for Chlorinated Pesticides in Food

Products

Chlorinated pesticides the economic poison employed to regulate the impact

of various pests in agriculture/ contaminate in crops and food stuffs. These are DDT,

BHC, aldrin, alteration, lindane.

Extraction and purification of the food sample follow the sample produce

procedure as employed in HPLC.

Procedure for the Analysis

Prepare the glass plate by coating silica gal slurry or alumina layer. In

adsorption TLC is to performed the layer of sorbent is activated by heating to 2000C

for 4 hours. The food sample containing chlorinated pesticides is applied as aspect

near one end of the plate. The plate is placed in a closed chamber saturated with

hexane.

The chromatogram is developed with chromogenic reagent 0.2% AgNO3 or

0.5% solution of p-methylamino hydrochloride made in sodium ethnoxide. Moisture

the plates by spraying distilled water.

RF values of Some Pesticides are aldnin, 079, DDT, 0.60, BHC 0.4, dieldrin

0.17, and methoxychlor 0.12.

HTPLC

High performance thin layer chromatography is a new techniques in which

TLC plates are coated with smaller, more uniform particles of controlled porosity.

This permits better detection of organochlorines in food stuffs.

QUESTIONS

1. Why is food analysis important ? Discuss the safrty of food.

2. What do you know about the moisture content of food ? how will you

determine moisture in vegetable oils and spices?

3. How will you analyse total ash, water-insoluble ash and acid-insoluble ash in a

food sample?

4. How will you determine or organophosphate insecticide in a food materials?

5. What are the common food adulterants? How will you analyse crude fibers as

adulterant in food products.

BLOCK-I

UNIT-IV

ANALYSIS OF WATER POLLUTION

Origin of waste water, types, water pollutants and their effects. Source of

water pollution-domestic, industrial, agricultural soil and radioactive wastes as

sources of pollution. Objectives of analysis-parameter for analysis-colour turbidity,

total solids, conductivity, acidity, alkalinity, hardness, chloroide sulphate, fluoride,

silica, phosphates and different forms of nitrogen. Heavy metal pollution-public

health significance of cadmium, chromium, copper, lead zinc, manganese, mercury

and arsenic. General survey of instrumental technique for the analysis of heavy

metals in aqueous systems. Measurements of DO, BOD, and COD. Pesticides as

water pollutants and analysis. Water pollution laws and standards.

UNIT-IV

ANALYSIS OF WATER POLLUTION

4.0 Introduction

4.1 Objectives

4.2 Water Pollution.

4.3 Water Pollutants.

4.4 Origin of waste Pollutants.

4.5 Effects of water Pollutants.

4.5.1 Physico-Chemical Effects.

4.5.2 Biological Effects.

4.5.3 Toxic Effects.

4.5.4 Pathogenic Effects.

4.6 Source of water Pollution.

4.7 Water Analysis.

4.7.1 Colour

4.7.2 Turbidity.

4.7.3 Conductivity.

4.7.4 Alkalinity.

4.7.5 Hardness.

4.7.6 Chlorides.

4.7.7 Sulphate.

4.7.8 Fluorides

4.7.9 Silica

4.7.10 Phosphates

4.8 Analysis of Different forms of Nitrogen

4.8.1 Ammonia

4.8.2 Nitrite

4.8.3 Nitrate

4.9 Heavy water pollution

4.10 Dissolved oxygen (DO)

4.11 Biochemical oxygen demand (BOD)

4.12 Chemical oxygen demand (COD)

UNIT-IV

ANALYSIS OF WATER POLLUTION

4.0 Introduction

Pollution:- The term pollution has been derived from the Latin word 'Pollution',

meaning 'defilement from polluere' to soil or defile (make dirty). In recent times the

word pollution is used to denote the contamination of water soil or air.

4.1 Objectives

Water pollution is harmful for our life. Water pollution may be divided into ground

water pollution , surface water pollution ,river water pollution, lake water pollution ,

sea water pollution. Water is an indispensable need of life. It is extremely necessary

to develop a suitable technology to protect at lest, the quality of drinking water not

only against biological hazardou pollutants and biodegradable organics.

4.2 Water Pollutions

1. Water pollution means the presence of any substance in water which affects

temporarily or permanently the quality of its usefulness.

2. The presence of any foreign material which is undesirable and objectionable

either solid liquid or gas in water causes water pollution.

3. Water is polluted when its basic properties are changed it becomes harmful

for human health.

4. Any toxic material in water which changes either chemical or physical

properties causes water pollution.

5. Addition of any unwanted substance which changes the composition.

6. Presence of radioactive substance in water which alters its basic properties

gives rise to water pollution".

7. Any unusual activities of man, which make water unfit for all living being

directly or indirectly, causes water pollution.

8. Reduction of oxygen, addition of pathogens and increase toxicity in water.

4.3 Water Pollutants

A water pollutant can be defined as a physical, chemical or biological factor

causing aesthetic changes or making it detrimental to aquatic life and those who

consume water.

1. In the form of chemicals:- Which remain dissolved in water.

2. Physical factors:- Among the physical pollutants, heat and radiation are

important which have a marked effect on organisms.

3. Biological factors:- Certain micro organisms present in water, specially

pathogenic species, cause diseases of man and animal.

Classification of pollutant

1. Common ions, salts or fixed dissolved soils.

2. Heavy metals and inorganic toxicants.

3. Organic material or BOD (Biological oxygen Demand)

4. Coliforms and other bacteria and viruses.

5. Nutrients particularly, N,P,K.

6. Pesticides other toxicants.

4.4 Origin of waste Pollutants.

The origin of waste water can be traced to its natural occurrence on the earth

formation by transformation and concentration of natural substances.

The generation of sewage and waste containing agrochemicals, certain

pesticides and surfactants. Many chemicals do not occur in nature and pollution

caused by them is entirely man-made. For ex. synthesis of various pesticides,

surfactants, radionuclide.

4.5 Effects of water Pollutants

4.5.1 Physico-chemical effects:- A large number of pollutants imparts colour,

taste and order and even unfit for domestic consumption. The changes is oxygen

content, temperature and pH value affect the chemistry of water.

The direct addition of nutrients through various sources enhances the algae and

other biological growth which when die and decomposes, they further deplete the

oxygen.

4.5.2 Biological effects:- The addition of pollutants leads to the shift in flora and

fauna due to homeostatic factors operating in the aquatic system. Most of the fresh

water algae are highly sensitive to pollutants and their elimination modifies the prey-

predatory relationship by breaking down the food chain.This result in change of the

whole plants and animals communities. The varieties of organisms decreases leaving

presence of only a few tolerate forms in the polluted conditions.

4.5.3 Toxic Effects:- These are caused by pollutants such as heavy metals,

biocides, cyanide and other organic and inorganic compounds. These chemical

(heavy metals, pesticides) are toxic to the aquatic organisms and many specially

non-biodegradable, accumulate in the body of organisms and bio-magnify along the

tropic levels causing long lasting effects.

4.5.4 Pathogenic effects:- Besides the chemical substances, a few water like

sewage, also contain several pathogenic and non-pathogenic microorganisms and

viruses. The clostridium porfringers and streptococcus faecalis causes various type of

food poisoning. Water born disease like cholera typhoid, colitis.

4.6 Sources of Water Pollution

1. Domestic Sewage:- Sewage consist of water born wastes of the community

and contain about 99% water and 1% of soil. It contain 65% are protein,

25% are carbohydrates, 10% of fats. The major problems associated with

sewage spread of enteric diseases, besides organic pollution which leads to

oxygen depletion and fish kill. Sewage also contain huge quantities of

nutrients in the form of nitrogen and phosphorus even after the secondary

treatment that often causes eutrophication.

2. Agricultural wastes:- Agricultural wastes usually originate in the form of

run off from the agricultural fields and animal farms. Modern agricultural uses

a large number of chemicals, called agrochemicals, in the form of fertilizers,

organic manure, pesticides, nutrients solution and others.

3. Industrial wastes:- The Industrial waste have the greatest potential for

polluting the recipient water. The nature and composition of industrial waste

depends upon the raw materials, processes and operational factors. Metal

plating industries, release substantial quantities of heavy metals and cyanide

in their wastes. The chemical industries release wastes with highly variable

composition which are often acidic or alkaline in nature.

4. Radioactive sources:- The radioactive substance are used for power

industry, heating homes, preserving food, fuelling, transport and as medicines

for curing disease. They can also be used to prepare nuclear bomb & nuclear

power plant.

The wastes from atomic reactors, hospitals etc. are most dangerous because

their radioactivity can't be destroy easily at human level. These wastes destroy the

aquatic plant and animals to a great extent. They generally cause gene mutation-

ionization of body fluids and chromosomal mutation.

4.7 Water Analysis

4.7.1 Colour

Pure water has no colour. The presence of humic acids, fulvic acids, metallic

ions, industrial effluents may give colour to natural water. Colour can be detrermined

by following two methods:

1. Platinum cobalt Method.

2. Forel-ule colour scale method.

1. Platinum cobalt method

This method gives a quantitative measure of the dominant spectral colour

(blue).

Colour Standard:- Dissolve 1 gm of crystalline cobalt chloride and 1.245 gm of

potassium chloro platinate in a small quantity of water. Then add 100 ml of conc.

then diluted to 1 litre. This solution has a colour value 500 colour unit. Prepare

standard by tilting 5.0, 1, 1.5, 2.0 etc. of above solution with distilled water to 50 ml

in standard nessler tubes. This solution has colour value of 5, 10, 15 respectively.

Indicate the colour value on each tube and protect them.

Methods:-

1. Centrifuge the sample at high speed to remove suspended matter.

2. Fill standard nessler tube with sample to the same level as that of standard

(50 ml)

3. Compare the colour of sample with that of various standard tubes held

vertically above a white surface and find one standard with same colour as

that of sample and read the colour value.

Note: If the sample shows a colour more than 70 units it should be diluted

with distilled water and the colour estimated is multiplied with dilution factor.

2. Forel-ule colour scale me that :- This method gives a qualitative recognition

of colour of sample.

Materials:- 1. Solution S-I: add 0.5g of CuSO4.5H2O to 5 ml strong NH4OH and dil to

100 ml with, distilled water.

Solution S-2: Add 0.5 g of K2CrO4.5H2O to 5 ml of strong NH4OH and dilute to 100

ml with distilled water.

Solution S-3: Add 5g of CaSO4 .7H2O to 5ml of strong NH4OH and dil. to 100 ml

with distilled water.

Empirical Forel: Ule colour scale is prepared by mixing different proportions of the

above solution (Solution I, II, III).

Method

1. centrifuge the sample so as to remove the suspended matter.

2. Fill the sample in clean tube and compare its colour with 22 mixtures of the

forel-use colour scale.

4.7.2 Turbidity

Turbidity in water is caused by suspended matter like clay, silt, organic

matter, phytoplanptons and other micro scopic organism.

Turbidity when caused (i) Largely because as phytoplankton, is considered as

an index of productivity, put on the contrary, when caused (ii) because of suspended

matter other than phytoplankton, it restricts the light penetration in water resulting

in reduced primary production (photosynthesis).

Material

1. Nephelometer (Turbiditymeter)

2. Sample Tubes: Made of colour said scratch-free glass.

3. Standard turbidity suspension : Dissolve 1g of hydrazine sulphate in distilled

water to prepare 100 ml of solution: (a) Dissolve 10g of hexamethylene

tetramine in distilled water to prepare 100 ml of solution. (b) Mix 5 ml of each

of the solution (a and b) in 100 ml volumeric flask and allow to stand for 24

hours at about 25C. Dilute it with distilled water to the mark. This is a

suspension having 400 NTU (Nephelometric turbidity unit) and can be stored

for about one month.

Dilute 10 ml of above stock solution (of 400 NTU) to 100 ml with distilled

water. This standard solution has 40 NTU and can be stored for a week.

Method

1. Set the Nephelometer at 100 using 40 NTU standard suspension. In doing so

percent of the scale will be equal to 0.4 NTU turbidity.

2. Shake the sample thoroughly and let the air bubbles subside.

3. Take the sample in nephelometer sample tube and find out the value on

scale. If the sample has turbidity more than 40 NTU, dilute it, so that its

turbidity can be read on the same scale.

Calculation = Turbiding = Mephelometer reading x 4 x dilution

factor.

4.7.3 Conductivity

The cell of the conductivity meter or salt bridge is filled with water sample

and the electrical conductivity (EC) is measured. It is expressed as Ds/m at 250C,

and mhos/Cm at 250C.

The Relationship between conductivity and salt concentration varies some

what depending on the ionic composition of the solution the electrical conductivity

provides a rapid and resorably accurate estimate of solute concentration.

Conductance is the reciprocal of resistance unit is ohm-1 or mhos or siemens(s).

The EC is directly proportional to the area (surface area) and inversely proportional

to the length (distance).

EC [Electrical conductivity] and a/l

EC= k a/l

a=area, l=lengtn

k= proportionality constant called specific conductance.

In case a=1 cm2, l-1cm / then conductivity =k

Measurement of Electrical conductivity

The instrument consist of an AC salt bridge or electrical resistance bridge and

conductivity cell having electrodes coated with platinum black.

Principle: A simple wheatstone bridge circuit is used to measure EC by null method.

The bridge consist of two known and fixed resistance r1,r2 and variable standard

resistance r4 and the unknown r3. The variable resistance r4 is adjusted until a

minimum or zero current flows trough the AC galvanometer. At equilibrium,

4

3

2

1

r

r

r

r

OR 4

2

1

3r

r

rr

Since conductivity is reciprocal of resistivity it is measured with the help of r3

Equipment and reagents

1.Conductivity meter and cell

2.Beaker

Standard potassium chloride solution (0.0 1m)

0.7456g of dry AR grade KCl is dissolved in freshly prepared double distilled

water and made to one litre. At 250C it gives an electrical conductivity of 1.413 in

mhos/cm/(ds/m). This instrument is to be checked and calibrated with this solution.

Methods

1. Take sample in 925 ml beaker.

2. Warm up the instrument for 20 minutes.

3. Use 0.01M KCl solution to calibrate the meter.

4. Rinse the conductivity cell with distilled water and then with the sample.

5. Temperature and cell constant corrections are adjusted on the conductivity

meter, if provided.

6. Connect the conductivity cell to meter and dip in the sample. Pass the current

and adjust the current by rotating the dial in such a way that maximum

sensitivity is obtained.

7. Read the conductivity value in ds/m. Direct reading may be obtained in digital

types of meters. Observed values of EC are multiplied by the cell constant

(usually given on conductivity cell) and a temperature factor to express

results at 250C, if instruments are provided with temperature compensations

in which reading directly comes at 250C. Operating manual must be read

before the operation of the instrument.

Sometimes water shows acidity due to presence of uncombined CO2, Salts of strong

acids and weak bases and mineral acids. For determing the acidity of water, it is

titrated with standard solution of strong base by using a suitable indicator.

Apparatus :

1. Conical flask

2. Pipette

3. Burette

Reagents :

1. Phenolphthalein and methyl orange in indicator.

2. N/100 NaOH Solution

Procedure :

1. Take 100 ml sample in a conical flask and add 2 drops of phenalphthalum

indicator, and titrate it with N/100 NaOH Solution.

2. Note down the volume used of N/100 NaOH from burette.

Calculation : Total Acidity as CaCO3 (mg/litre)

=)(

1000100

mltakensampleofVolume

XNNaOHofvolumeused

N=Normally of NaOH solution

4.7.4 Alkalinity

Water shows alkalinity due to presence of salts of weak acids, and strong

bases the alkalinity in water is caused due to presence of (1) carbonates (CO3--) (2)

Bicarbonates (HCO3-) (3) hydroxides (OH-) Alkalinity can easily be determined by

titration using Phenolphathalein (work in alkaline pH range above 8.2) or methyl

orange indicator (work in acidic pH range below 6.0)

Reagents

1. Phenolphthalum Indicator: 0.25% solution in 60% ethyl alcohol.

2. Methyl Arrange Indicator: 0.5% solution in 95% alcohol.

3. Standard Sulphuric Acid: Dil. 2.8 ml of Conc. H2SO4 to 1 litre with distilled

water, dilute 200 ml of this solution to again 1 litre for getting .02 NH2SO4

standardize this solution.

Method :

1. In a porcelain dish 5 ml of the sample is diluted with distilled water to about

25 ml.

2. Pink colour produced with a few drops (2-3) of phenolphathalein indicates

presence of carbonates and it is titrated with 0.02N sulphuric acid until the

colour just disappears because of alkali carbonate being converted to

bicarbonate. This burette reading its designated as (Al)

3. To the colourless from this titration (or to the original sample of water its

there was no colour with phenopthalein) 1-2 drops of methyl orange or

methyl red indicator are added and the titration continued till the colour

changes from yellow to rose red.

4. Record the final reading.

Suppose A ml of acid used for titration with phenolphthalein.

B=ml of acid used for total titration (with phenolphthalein and methyl orange

both).

The observation can be summarised in the following ways.

(a) When A=B

Total Alkalinity of hydroxide (mg/litre) =sample of ml

1000A

(b) When B2

1A

Total Alkalinity (mg/litre)= sample of ml

1000B

(a) When A=1/2B

Total Alkalinity (mg/litre)=alkalinify

carbonate

sampleofml

B

1000

(b) When B2

1A

Total alkalinity, (mg/litre)= sample of ml

1000B

Carbonate alkalinity, (mg/litre)=sample of ml

1000A2

(c) When A=0

Total alkalinity of Bicarbonate = sample of ml

1000B

4.7.5 Hardness

(a) Temporary Hardness : It is due to the presence of bicarbonates of Ca2+

and Mg2+ . It may be removed by boiling the water.

(b) Permanent Hardness : This hardness can't be removed by boiling the

water. It is due to the salts of Ca, Mg, Fe, Strontium.

Reagents

1. Ericherome Black T indicator: This is prepared by mixing 0.5g of erichrome

black and about 100g of NaCl in 20 ml of water by warming. The solution is

stable for 100 days.

2. Ammonia Buffer: Take 16.9g of NH4Cl in 143 ml. of liquor ammonia and dilute

to 250 ml with distilled water. In presence of metallic ions, use borate buffer.

Take 20g of barax (Na2B4O7 10H2O) in 400 ml of distilled water. Dissolve 5g

of NaOH and 2.5g of sodium supplied in 50 ml of distilled water, mix with

borex solute on and dilute to 500ml with distilled water.

3. Standard EDTA Solution (0.01N): Ethylene Diaminetetra-acetic acid

disodium salt is prepared by dissolving 2g in distilled water to which 0.05g of

magnesium, Chloride is added and diluted to 1 litre.

Method:

1. Take 100 ml of sample in a conical flask and add 1 ml. of ammonia buffer and

2 drops of Erichrome black T indicator. Shake the solution well.

2. Titrate it with standard (0.01 N) EDTA. The colour Charge is from wine red to

blue or bluish green.

3. At the end point no tinge of red colour should remain.

4. Note the volume used for EDTA solution from burette. This is the end point

reading.

Calculations:- Hardness (mg/litre) as CaCO3 can be obtained by

following formula:

Hardness (mg/litre) = taken sample of ml

1000XN )ml( used EDTA of Volume

N= Normality of EDTA solution.

4.7.6 Chlorides

Chloride is in variably present in small amounts in almost all natural waters.

The estimation of chloride may be carried out by Mohr's method, when the electrical

conductivity of water sample is greater than one ds/m at 250C

Reagents

1. 0.02 N sodium chloride 1.170g of NaCl is dissolved in double distilled water

and made to 1 litre.

2. 0.02N silver nitrate 3.40g of silver nitrate is dissolved in double distilled water

and made up to one litre. This to be standardized against the standard NaCl

solution and stored in amber (brown) coloured bottle away from light.

3. Potassium chromate indicator 5.1 of aq. solution of pure K2CrO4

Methods :

1. Take 5 ml of sample in a porcelain dish and dilute it to about 25ml with

distilled water .

2. Add 5 to 6 drops of K2Cr2O4.

3. Titrate with standard AgNO3 solution with stirring till the first brick red tinge

appears.

4. Note down the volume of AgNO3 solution used from burette.

Calculation : Chloride in multi equivalent/litre

=takensampleofml

AgNOofVolumeNOAgofNormality

1000 33

Chlorides in gram/litre

=takensampleofml

weighteqAgNOofVolumeAgNOofNormality

)5.35(cl . -

33

4.7.7 Sulphate

Sulphates are generally found in hard water. Suphate can be determined

gravimetrically, Colourimetrically and Turbdionetrically. The procedure given here is

based on EDTA titration described by Jackson (1973) .

Reagents

1. 0.02N MgCl2, BaCl2 and EDTA AR grade BaCl2 (2.44 g/l) can be directly

weighed out and dissolved. MgCl2 being highly hygroscoic, the required

quantity of AR magnesium metal of MgCo3 may be dissolved in a little excess

of dilute HCl and made up to the volume. The EDTA solution must be

standardized against 0.02N CaCl2.

2. Buffer solution : This consist of 8.25g of NH4Cl plus 5 ml of NH4OH (Sp. gr.

0.88) in a litre. the amount of NH4OH may be so adjusted that 10 ml of this

solution added to 50 ml of water sample can give pH of 10.

3. Standard CaCl2 solution : 0.02N of solution is prepared by dissolving 1.001g of

dried CaCO3 (AR) in minimum quantity of dilute (1+3) HCl and made upto 1

litre with water.

4. Erichrome Black T indicator: 0.5g of the indicator and 4.5g of hydroxylamine

hydrochloride dissolved in 100 ml of 75% ethyl alcohol.

Method:

Take 100 ml of sample and add a few drops of methyl orange indicator and

slightexcess of HNO3. Boil the mixture to remove dissolved CO2. Add 10 ml of

standard CO2. Add 10 ml of standard BaCl2 solution in the boiling solution. Allow to

Cool down and make the volume up to 150 ml of clean supernatant liquid into a

beaker. Add 1 ml of Buffer solution and some amount of Erichrome Black T indicator

titrate with EDTA solution until a permanent blue colour is produced indicating end

point. Calculation: Suppose 25ml of sample is taken for precipitation of sulphates

then the following formula can be used.

10ml of BaCl2 solution = 10gm of CaCo3 = 10ml EDTA solution.

SO-24 (mg/litre)= Titrate value in hardness + value equivalent volume

estimated of BaCl2 used

Titre value insulphate 25

100098.0

determination

Note:

If the sulphate in water is more than 100 mg/litre then volume of barium

chloride should be in creased.

4.7.8 Fluorides

Fluorides are more commonly found in ground water than in surface water.

The main source of fluoride in water are apatite and mica. The maximum permissible

limit of fluoride in drinking water is recommended to be 1.5 mg/kg by WHO.

Materials and Reagents:

1. Spectro photo meter

2. Alizarin red solution:- Dissolve 354 mg of zirconyl Chloride octahydrate in 600

ml of destilled water. Add slowly 33.3 ml of con. sulphuric acid followed by

100 ml of con Hcl. Cool and further add distilled water to make the volume 1

litre.

3. Standard Fluroide solution :- Disolve 221 mg of sodium fluoride distilled water

and make the volume 1 litre. This stock solution contains 10 mg F/l. Prepare a

series of standard fluorides solutions by taking 0,10,15, 20 .......ml stock

solution in volumetric flask and diluting it to 100 ml. These contain 0,1,1.5,2

.... mg F/l respectively.

Method:

1. Take 100 ml of sample in a flask and add 5 ml each of alizarin red solution

and zirconyl acid solution.

2. Wait for 1 hour and then note the absorbance on spectrophotometer at 520

nm.

3. Run blank using distilled water.

Preparation of Standard Curve:

1. Run the standard of various concentrations in similar manner and record.

2. Plot standard curve between concentration and absorbances obtained for

standard solutions.

3. Determine the fluoride content of the sample by comparing its absorbance

with standard curve and express the result as mg f/l.

4.7.9 Silica

Silica in water is present as silicate. In concentration in natural water is

considerably high. Silica is an important structural constitunt for diatoms and many

sponges. The assimilation of silica and subsequent sedimentation by diatoms is the

major source of silica in water.

Materials and Reagents:

1. Hydrochlaric Acid (50%) : Add 50 ml concentrated hydro chloric acid to

50 ml of distilled water.

2. Ammonium Molybdate Solution (10%) : Dissolve 20g of ammonium

molybdate in distilled water and make the volume to 200 ml. Adjust the pH

between 7 and 8 by adding ammonium hydroxide keep the solution in a

polyethylene bottle.

3. Oxalic acid solution (10%) : Dissolve 20g of oxalic acid in distilled water

and make the volume up to 200 ml.

4. Standard silica solution: Add 0.6714g of sodium fluorosilicate in a little

distilled water and heat to dissolve. Further add distilled water to make the

volume 1 litre. This stock solution contains 100mg Sio3-Si/litre. Dilute the

stock solution with distilled water to prepare a series of standard silica

solution, (take 0, 5, 10 .... and 50ml) stock solution in 100ml of volumetric

flask and make the volume with distilled water. This will give working

standards having 0, 5, 10 .... 50 mg Sio3- Si/litre.

Method

1. Take 50 ml of sample in on Erlenmeyer flask and add 1 ml of HCl and 2 ml of

ammonium molybdate solution.

2. Wait for about 10 min and add 1.5 ml of oxalic acid solution.

3. Mix thoroughly and record the absorbance on spectrophotometer at 410nm.

4. Carry out blank with distilled water.

5. Run standard silica solution in similar manner and record absorbance

readings. Plot a standard curve between absorbance and concentration of

standard solutions. Deduce the silica content of sample from the standard

curve.

6. Express results in mg Sio3-Si/litre.

4.7.10 Phosphates

Materials and Reagents :

1. Spectrophotometer.

2. Per chloric acid 70%.

3. Phenolphthalien indicator. Dissolve 1.0g of phenolphthelien in 100ml ethyl

alcohol and 100ml of distilled water.

4. NaOH Solution (1 N): Dissolve 4g NaOH in distilled water and make volume

to 100ml.

5. Reagent A: Weight 1g of ammonium molybdate and 0.02g of potassium

antimony Tartrate in 1000ml volumetric flask. Add 16 ml of concentrated

H2So4 slowly by touching outlet point of measuring cylinder to the inner neck

of the flask. Add distilled water slowly, shake and make the volume upto the

mark.

6. Reagent B: Weight 0.88g of ascorbic acid and dissolve in 1 litre of reagents A.

It should be prepared fresh.

7. Standard phosphate solution: Dissolve 2.19g of dried anhydrous potassium

hydrogen phosphates in Distilled water and make upto 500ml mark. Take 10

ml of this solution and add distilled water to make 1 litre of stock containing 1

mg P/I. Prepare standard phosphorus solution of various strengths by diluting

the stock solution with distilled water.

Methods:

1. Take 25 ml sample in an Erlenmeyer flask and evaporate to dryness.

2. Cool and dissolve the residue in 1 ml of perchloric acid.

3. Heat the flask gently, so that the content be comes colourless. Cool and add

10 ml distilled water and 2 drops of phenolphthalic in indicator.

4. Titrate against sodium hydroxide solution until pink colour appears. Make up

the volume to 25 ml by adding distilled water.

5. Transfer this into 50 ml volumetric flask and 10 ml of reagent B.

6. Make the volume to 50 ml with distilled water and let the blue colour develop.

Wait for 30 minute and record the absorbance on spectrophotometer at 660

nm.

7. Run simultaneously a distilled water blank in similar manner.

Calculation : P mg/l = sampleofVolume

mlinPmg

100050

4.8 Analysis of Different forms of Nitrogen

Nitrogen (Ammonia/Nitrile/Nitrates and organic Nitrogen)

4.8.1Ammonia: Ammonical–Nitrogen is determined Colorimetrically as well

as volumetrically as described below:

Colormetric Method

Material and reagents :

1. Spectrophotomer.

2. Phenol nitrogen prusside solution: Dissolve 30g of phenol in 1000ml of

distilled water. Add 2ml of freshly prepared 1.5% w/v aqueous solution of

sodium nitroprsside.

3. Alkaline hypochlorite, solution: Dissolve 20g of sodium hydroxide in some

distilled water and add 5.4 ml of 10% solution of hypochlorite. Make the

volume to 1000ml with distilled water.

4. Standard ammonium chloride solutions: Dissolve 1.91 g of anhydrous

ammonium chloride in distilled water an make volume to 500 ml. This stock

solution contain 1 g NH4+/L or (1.22g NH3/L.). Prepare range of standard

solution by taking stock solution as o,1,2,3,4 .... and 6 ml and diluting it with

distilled water to 100 ml.

Method:

1. Take 40ml sample in a 50ml volumetric flask add 4 ml each of

phenolnitroprusside solution and alkaline hypochloric solution.

2. Make up the volume of contents to 50 ml by adding ammonia-free distilled

water.

3. Keep it in a dark place at 250C for about 1 hour.

4. Record the absorbance on spectrophotometer at 62 nm use distilled water as

blank.

5. Process the standard ammonium chloride solution of different concentration

in similar way and record the absorbance for each.

6. Plot the concentration of ammonium ions in sample in mg NH4+/L against

arrogance and prepare standard curve. Calculate concentration of unknown

with the help of curve.

Volumetric Method:

Materials and Reagents

Micro-Kjeldhal distillation assembly.

1. Hydrochloric acid (0.01N): Dilute 8.34 ml of 12N conc. HCl with a distilled

water to prepare 100ml of 1.0 N HCl. Dilute 10ml of this HCl with Distilled

water to prepare 1 litre of 0.01 HCl.

2. Boric acid cum Indicator solution: Dissolve 4 g of boric acid in 100 ml of

warm distilled water. Prepare 0.5% bromocresol green solution and 0.1%

methyl red solution in ethyl alcohol mix Bromo cresol green and methyl red

solutions in the ratio of 2:1 to make a mixed indicator. Add 5 ml of this mixed

indicator to 100 ml of Boric acid solution. If the colour of solution becomes

blue add 0.01N HCl until it terms faint pink to brown.

3. Borex buffer solution : Add 4g of borax crystals to 100 ml of distilled water

and heat to dissolve.

Method

1. Take 50 ml of sample in micro-kjeldhal distillation flask and 1 ml of borax

buffer solution.

2. Put 5 ml of Boric acid cum indicator solution in a conical flask. Place it below

the condensor so that the dip of outlet of condenser is dapper in contents of

conical flask.

3. Heat the kjeldhal flask containing water sample

4. Continue distillation until about 40 ml of destillate is collected in the conical

flask.

5. Remove the conical flask having distillate which turns blue due to dissolution

on of ammonia.

6. Titrate the distillate in conical flask against 0.01N hydro chloric acid. turning

of blue colour to taint pink brown indicates the end point.

7. Run a blank with distilled water in a similar way.

4.8.2 Nitrite

Nitrites can be determined colourimentrically by EDTA method and

sulphonilamide method. The EDTA method in the followings.

Materials photometer.

1. Spectrophotometer.

2. EDTA solution: Dissolve 0.5g of disodium salt of EDTA in distilled water to

prepare 100 ml of solution.

3. Sulphanilic acid solution : Dissolve 600 mg of sulphuric acid in about 70

ml of concentrated HCl and make the volume of content to 100 ml by further

adding distilled water.

4. Naphthylamine HCl solution : Dissolve 0.6g of Naphtylamine HCl in a

little distilled water. Add 1ml of conc. HCl and make the volume to 100 ml by further

adding distilled water.

5. Sodium acetate solution : Dissolve 27.2g of sodium acetate in distilled water

to make volume to 1 litre.

Methods :

1. Take 50 ml filtered sample in an Erelenmeyer flask and add 1ml of each EDTA

Soln Sulphonic acid and naphthylamine HCl one after the other appearance

of wine red colour indicates the presence of nitrites.

2. Record the absorbance of this solution on spectrophotometer at 520 nm.

3. Carry out blank with distilled water.

4. Run standard nitrite solution in similar way and record the absorbance for

different conc of standard solutions and deduce the nutrite nitrogen content

of sample by comparing its absorbance with the standard curve.

4.8.3 Nitrate

Phenol desulphonic acid method

Materials and Reagents:

1. Spectrophotometrs

2. Hot water bath

3. Phenol disulphide acid: Dissolve 25g as white phenol in 150 ml of Conc. H2So4

then again add 85 ml of conc. H2So4. That it for about 2 hours on a water

bath, cool and keep the solution in a dark bottle.

4. Liquor ammonia (Lr grade) : It is diluted with equal volume of water.

5. Standard nitrate solutions: Dissolve 0.722g of anhydrous patassium nitrate in

distilled water to prepare l litre of stock solution. This stock solution contain

100mg NO3 /l.

Method:

1. Take 25ml of sample in a porcelain dish 58 and vaporate it to dryness on a

hot water bath.

2. Add 3 ml of phenol disulphuric acid and dissolve the latter by rotating the

dish.

3. After 10 minute 15 ml of distilled water is added and stirred with a glass rod.

4. Add ammonia (1:1) slowly with mixing till the solution is alkaline as indicated

by the development of yellow colour due to the presence of nitrate. Then add

another 2ml of ammonia and the volume made up (100 ml) with distilled

water.

5. Intensity of yellow colour is red in the colorimeter at 420nm (blue filter).

6. Add 5 ml of distilled water and 1.5 ml of potassium hydroxide solution.

Total Organic Nitrogen (TON)

Materials:

1. Micro – Kjeldahl distillation assembly.

2. Digestion mixture. Dissolve 16.25g of potassium sulphate in 200ml of distilled

water. Add 0.4g of mercuric oxide and slowly 25ml of conc. H2SO4 further add

distilled water to make the volume 250 ml

3. Hypo solution: Dissolve 50g of sodium hyroxide in 200ml of distilled water

and add 10g of sodium thiosulphate. Make up the volume to 250 ml by

adding distilled water.

4. Boric acid solution : Dissolve 1g of boric acid in distilled water to make 100 ml

of solution.

5. Mixed Indicator : Prepare 0.1% methyl red solution and 0.5% Bromo cresol

green solution in 95% ethyl alcohol. Mix the methyl red and bromo cresol

green solution in 1:2 ratio.

6. Hydrochloric acid (0.01N): Dilute 8.3 ml of conc. HCl with distilled water to

prepare 100ml of 1.0 N HCl. Dilute 100ml of this 1.0 NH4 with distilled water

to prepare 1 litre of 0.1N HCl. Take 100ml of 0.1N HCl and dilute to 1 litre

with distilled water to get 0.01 HCl.

Method:

1. Take 200ml of sample in an evaporating dish and evaporate to dryness.

2. Add 4ml of digestion mixture to the residue and dissolve it in about 20ml of

distilled water.

3. Heat the solution to fuming for over 15 min and cool.

4. Transfer the digest to micro kjeldahl distillation assembly and add about 3-5

ml of hypo solution.

5. Take 5ml of Boric acid solution containing 2-3 drops of mixed indicator in a

conical flask and place the flask below the condensor that the tip of outlet of

the condenser is dipped in contents of conical flask.

6. Heat the Kjeldahl flask: Continue distillation for about 10 mm. Remove the

concial flask having. destillate.

7. Titrate the distillate against HCl end point is determined by change of blue

colour to pink colour.

8. Also run a blank using distilled water in similar way.

Calculation T.O.N (g/k) = aliquotofVolume

NBT

141000)(

Where

T= Volume of titrant HCl used against sample (ml)

B= Volume of titrant (HCl) used a against blank (ml)

N= Normality of titrant (0.0)

The atomic weight of N is 14

4.9 Heavy Metal Pollution

Water pollution problem exists every where in the country and are increasing

day-by-day around inertial and urban countries.

Metal and their toxicity: The power of toxicity varies from metal to metal. The

term toxicology can be defined as a branch of science which deals with the study of

adverse and harmful effect of chemical agents on any biological system.

Types of Toxicology:

(a) Clinical Toxicology

(b) Industrial Toxicology

(c) Forensic Toxicology

(d) Environment Toxicology

(e) Economic Toxicology

1. Cadmium (Cd): Cadmium does not exist free in nature and there is no

specific are from which it can be obtained. Cadmium is obtained from refining

of zinc, and copper as by product.

Uses:

1. Cadmium is used in Industries as protective Coating for iron, steel and

copper.

2. In electronic equipments Ni-Cd batteries are used. Toxicity and diseased

cadmium dust, fumes and the atmosphere. Cadmium toxicity of ever 50 mg

quantity causes various disease in man such as.

3. Cadmium toxicity is responsible for vomiting, loss of consciousness.

4. It cause retardation of growth, diformity in bone hypertension impaired

kidney functioning, impaired reproductive function and formation of tumor.

5. Inhaling of cadmium dust or fumes causes chocking of nose, coughing.

2. Chromium : Chromium occurs of chrome iron ore.It is also found in soil

and plants. The quality of chromium in a human is almost about 6mg chromium

attached with the protein B-glabuline and disturbed in different parts of body like

spleen, tests, liver, brain,Heart.

Uses:

(a) Steel manufacturing, Photographic work.

(b) Production of jet engines

(c) Preparation of paints, electric cells matches

3.Copper

Occurance:In nature, copper occurs in sulphide ores copper is present in liver and

brain in blank pepper its is present as at 53 ppm whereas in oysters its quantity is

137 ppm. toxicity and disease copper is an industrial health nazard. More than 470

mg copper in human body is toxic and causes many disorders in the body.

4. Lead

Occurance: ores are galena, and its sulphide. Lead is present in the bones the

concentration of lead increases with age lead is not an essential metal for

mammalians. Lead is usually deposited in bones and some soft tissues. It is also

retained by animal in lever. Kidney muscle etc.

Under some Specific conditions lead becomes Stimulatory and enhances (a)

protein synthesis (b) DNA Synthesis (c) cell replication. Toxicity and Disease: About

800 mg lead creates toxicity inhuman beings resulting in lead poisioning. Due to lead

paisioning a number of body disorders are caused.

Generally, lead toxicity is due to the concentration of diffusion of Pb in soft

tissues Another possible common mechanism. For Pb toxicity is formation of

metallotheonic.

5. Zinc

Occurance: Zinc is not found in free form, it is present in ores. These are

(a)Sulphide (b) Silicate ore.

In human body

(i) Muscles – 65% Zinc

(ii) Bones – 20% Zinc

Toxicity and diseased : More than 165 mg zinc causes some disorders in human

body. It cause Vomitting, cramps, Nausea.

6. Manganese

Occurance: Manganese occurs in nature as oxide as

(a) pyrolusite (b) Magnatite (c) Braunite

(d) tephroite

Manganese is also found in:-

1. Sea-water-an amount of | ppb.

2. In human body about 12 mg.

Mn is used in industry in the formation of

(a) Alloys

(b) Dry cell Batteries

(c) Fire works

(d) glass and cermanic Industries

Mn is less toxic but Mn is toxic when its in concentrate form. it is more than

100 ppm in human body it causes following disorder and Blindness, fever etc.

7. Mercury

Occurance: Mercury occurs as native metal mixed with its ores. The human body

contain about 13 mg mercury 70% of which present in muscles tissues. In human

body mercury is found in kidney, lever, Intestinal and colon walls, brain, heart and

lungs. Toxicity and disease mercury and its salts are severe health hazards. It is

toxic more than 100mg causes body disorder. Inorgonic form of mercury is also

injurious to health.

Mercury is converted into methyl mercury salt and dimethyl mercury by micro

organisns, which escape into atmosphere. Blood serum protein from complex are

responsible for killing of fish in rivers and oceans.

From Industries, CH3Hg Settle as sediment at the bottom of water bodies

from where fish trap. Mercury salts. If such types of mercury contaminate fish are

used in food they cause neutrotoxic minanata disease.

Body tissue retention is greater for CH3Hg+ than for Hg2+ salts. The toxic

action is due to crowding of Hg2+ ions around the immediately available thiol groups

of proteins and delay in distribution of these ions among rest of thiol group

throughout the body.

8. Arsenic

Occurance: Arsenic occurs in nature as a brittle metal. It is present in following

forms:

(a) in marine water – 5 ppb

(b) in earth's crust- 2 ppb

(c) in human body - about 18 mg found in tissue

(d) in blood- about 25 gm.

Arsenic is found in living body particularly in hair and spleen, in erythrocytes,

here arsenic binds globin part of naemoglobin. Compounds of arsenic are absorbed

easily by skin of human being.

Toxicity and Disease : Arsenic trioxide AsO3 is more toxic than As2O5. Its large

quantity in human body (more than 25mg) cause many disease, like diarrhea,

Vomiting, Nausea, Skin Eruption, Inflammation, Death.

limits of some heavy metals in drinking water are prescribed by the

Government of India.

Metals Permissive limit Excessive limit

Chronium – 50

Copper 1000 3000

Manganse 5000 15000

Zinc – 200

Iron 300 1000

4.10 Dissolved Oxygen (DO)

Dissolved Oxygen (DO) in water is an index of physical and Biological

processes going on non-polluted surface waters are generally saturated with

dissolved oxygen.

1. Diffusion from air/absorption from air

2. Photosynthetic activist within water by vegetation etc. Oxygen is consider to

be a limiting factor, especially in lakes and in waters with a heavy load of

organic material organisms have specific oxygen requirement. Low dissolved

oxygen may prove fatal for many organisms for their survival.

Oxygen meter method:

Material :

1. Oxygen meter with dissolved oxygen probe

2. Electrical stirrer

3. 5% sodium sulphite solution

Methods

Read the operation manual carefully and adjust the instrument accordingly.

Dip the Do probe in 5% Sodium sulphate solution with constant stirring. Now dip the

D.O. probe in water. Sample being constantly stirred and record the dissolved

oxygen in mg/litre from the scale.

Winkler's Method

Principal : Oxygen combines with Mn(OH)2 and form higher hydroxides which on

subsequent acidification in the presence of iodine, liberate iodine in an amount

equivalent to the original dissolved oxygen content of the sample.

Materials and reagents:

1. BOD bottles (100-300ml)

2. Manganous sulphate solution: Dissolve 100g of manganous sulphate in 200ml

of previously boiled distilled water and filter the solution.

3. Alkaline potassium iodine solution. Weight 50g of KI, and 100g of potassium

hydroxide. Dissolve the chemicals in 200ml of previously boiled distilled water.

4. Sodium thiosulphide solution (0.025N): Dissolve 6.205g of sodium, in one litre

previously boiled distilled water and add a pallet of NaOH as a preservative.

Keep it in coloured bottle.

5. Starch Indicator: Dissolve 1g starch in 100 ml warm distilled water and add a

few drops to toluene as preservative.

6. Concentrated sulphuric Acid: Sp. gravity 1.84.

Method :

1. Take a glass stoppered BOD bottle of known volume (100-300ml) and fill it

with sample avoiding any bubbling. No air should be trapped is bottle after

the stopper is placed.

2. Open the bottle and pour is each 1 ml of manganese sulphate and alkaline

potassium Iodide solution using separate pipettes. If the volume of sample is

over 200 ml add 2 ml of each reagent instead of 1 ml.

3. A precipitate will appear. Place the stoper and shake the bottle thoroughly.

Sample at this stage can be stored for a few days, if required.

4. Add 2ml of sulphuric acid to dissolve the precipitate, shake thoroughly.

5. Transfer gently avoiding bubbling whole content, or a known part of it in a

conical flask put a few drops of starch indicator. Titrate against sodium

trisulphate solution and note the end point when initial blue colour

disappears.

Calculation :

(i) If whole content is used for titration

D mg/l= 32

1

VV

10008NV

(ii) If a fraction of the content is used for titration

D mg/l=

)V

VV(V

10008NV

2

3

24

1

Where D.O - Dissolved Oxygen

V1 = Volume of titrant (ml 1)

V2 = Volume of sampling bottle after placing the stopper (in ml)

V3 = Volume of manganous sulphate + potassium iodide added

V4 = Volume of fraction of the content used for filtration (ml)

N = Normality of titrant (0.025) the equivalent weight of oxygen is 8.

4.11 Biochemical oxygen Demand (BOD)

As the amount of oxygen required by micro-organisms to stabilize biologically

decomposable organic matter in the waste water under aerobic conditions.

Tests of BOD : This can be evaluated by measuring oxygen con. in 9 sample

idometrically before and after incubation in the dark at 200C for 5 days. Excess

dissolved oxygen must be present during the whole incubation. Sometimes a culture

of bacteria is also added so that more of the organic matter is used up during the

incubation.

Materials and Reagents:

1. BOD incubator, BOD bottles

2. All reagents used in determination of dissolved oxygen as discussed in

foregoing pages.

3. B.O.D. free water: Pass the deionized glass distilled water through a column

of activated carbon and redistilate.

4. Phosphated buffer solution : Dissolve 42.5g potassium dihydrogen phosphate

in 700 ml BOD free water and add 8.8g NaOH. Adjust the pH at 7.2 add 2g

ammonium sulphate and dillute to 1 litre with BOD free water.

5. Magnesium sulphate solution: Dissolve 82.5g of magnesium sulphate in BOD

free distilled water to prepare 1 litre of solution.

6. Calcium chloride solution : Dissolve 27.5g of anhydrous calcium chloride in

BOD free distilled water to prepare 1 litre of solution.

7. Ferric chloride solution: Dissolve 0.25g of ferric chloride in 1litre of BOD free

distilled water.

8. Sulphuric acid (1N): Add 2.8 ml of conc. sulphuric acid to 100 ml of BOD free

distilled water.

9. Sodium hydroxide solution (1N): Add 4g of sodium hydroxide in BOD free

distilled water and make the volume 100 ml.

10. Aruglthiourea solution : Dissolve 100 mg of Aruglthiourea in distilled water

and make the volume 1 litre.

Method

1. The required volume of BOD free distilled water in a glass container by

bubbling compressed air for 1 to 2 days to attain dissolved oxygen saturation.

After saturation it is kept at 200C for at least one day. Add per litre of this

water 1 mL each of phosphate buffer solution. If required, add requisite

amount of seed (sewage) also.

2. Dilution of sample : Adjust the pH of sample to neutral. Dilute the sample

with appropriate amount of water according to the expected BOD current of

the sample.

3. Fill two sets of BOD Bottles and add 1 ml of Aruglthiourea solution to each

bottle. As for as possible avoid entrapping air bubbles in BOD bottles.

4. Stopper the bottle immediately.

5. Determine the dissolved oxygen content. Take out the battles after 5 days

and determine immediately their dissolved oxygen content (Ds) Calculations :

BODs (mg/l) = (D.O-Ds)×Dilution factor Dissolve oxygen after 5 days sample

factor.

4.12 Chemical Oxygen Demand (COD) The amount of oxygen required for

oxidation of organic compound which are present in water by means of reaction.

Substances such as potassium dichromate and potassium permangate, potassium

dichromate ion is most suitable oxidant.

Principle : Organic matter decomposes poses and produces carbon dioxide and

water when it is boiled with a mixture of potassium dichromate and sulphuric acid.

Amount of potassium dichromate in the sulphuric acid medium and the excess

dichromate is titrated against ferrous ammonium sulphate (FAS).

Material and Reagents:

1. COD reflux unit consisting of flat bottom flask with ground glass Mouth and

leibig's condenser.

2. Hot water bath or heating mantle.

3. Potassium dichromate solution (0.25N): Dissolve 12.25g of LR grade

potassium dichromite previously dried at 1030C in distilled water.

4. Dry powder of silver sulphate.

5. Conc. H2SO4.

6. Ferroin Indicator solution: Dissolve 0.695 g of ferrous sulphate and 1.485g as

1110-phenethroline in distilled water to make 100 ml.

7. Standard ferrous ammonium sulphate solution (0.25N): Dissolve 98g of

ferrous ammonium sulphate in Distilled water, dilute add 20 ml of sulphuric

acid, cool and dilute to 1 litre by further adding distilled water to standardize

this solution/dilute 25 ml of potassium dichromate solution to about 250 ml

with distilled water, add 20 ml of sulphuric acid and cool it.

Normality of FAS = )(

25.0O 722

mLFASofVolume

CrKofVolume

Methods :

1. Take 20 ml of sample in the flask of reflux unit and add 10 ml of

patassium dichromate solution, pinch of each silver sulphate and mercuric

sulphate and 30 ml of H2SO4 acid.

2. Attach to the moush of flask and heat the flask on a hot water bash or

heating mantle for at least 2 hours to reflux the contents.

3. Cool the flask, detach from unit and dilute its contents to about 150 ml by

adding distilled water.

4. Add 2-3 drops of forroin indicator solution and titrate against ferrous

ammonium sulphate solution. At the end point blue green colour of contents

changes to reddish blue.

Calculation : COD (mg/Le)= )mL( sample of Volume

81000N)TB(

QUESTIONS

1. What is the origin of waste water ? Describe the water pollutants and their

effects.

2. What are the sources of water pollution? Give details about industrial wastes

as source of pollution.

3. How do the pesticides and radioactive wastes pollute drinking water ?

4. How can the BOD be evaluated in a water sample?

5. Determine the presence of heavy metals in water by atomic absorption

spectrophotometer.

BLOCK-I

UNIT-V

ANALYSIS OF SOIL, FUEL, BODY FLUIDS AND

DRUGS

(a) Analysis of Soil: Moisture, pH, total nitrogen, phosphorus, silica, lime

magnesia, manganese, sulphur and alkali salts.

(b) Fuel Analysis : Solid, liquid and gas. Ultimate and proximate analysis

heating values-grading of coal. Liquid fuels-Flash, aniline point octane number and

carbon residue. Gaseous fuels-producer gas and water gas-calorific value.

(C) Clinical Chemistry : Composition of blood-collection and preservation of

samples. Clinical analysis. Serum electrolytes, blood glucose, blood urea nitrogen, uric,

albumin, globulins, barbiturates, acid and alkaline phosphatases. Immunoassay :

principles of radio immunoassay (RIA) and applications. The blood gas analysis - trace

elements in the body.

(D) Drug Analysis : Narcotics and dangeorous drugs. Classification of drugs.

Screening by gas and thin-layer chromatography and spectrophotometric

measurements.

UNIT-V

ANALYSIS OF SOIL FUEL, BODY,FLUIDS AND

DRUGS

5.0 Introduction

5.1 Objective

5(a) Analysis of Soil

5a.1 Introduction

5a.2 Determination of moisture

5a.3 pH measurement

5a.4 Analysis of total nitrogen

5a.5 Analysis of phosphorus

5a.6 Analysis of silica

5a.7 Analysis of lime

5a.8 Analysis of Magnesium

5a.9 Analysis of Manganese

5a.10 Analysis of Sulphur

5a.11 Analysis of Alkali-salts

5(b) Fuel Analysis

5b.1 Solid, Liquid & Gaseous Fuels

5b.2 Gaseous Fuels

5b.2.1 Producer Gas

5b.2.2 Water Gas

5b.3 Analysis of Coal

5b.4 Flash Point

5b.5 Aniline Point

5b.6 Octane number

5b.7 Calorific Value

5(c) Clinical Chemistry

5c.1 Composition of blood

5c.2 Collection and preservation of samples of blood

5c.3 Analysis of Serum electrolytes

5c.4 Estimation of serum proteins

(Albumin and globulin)

5c.5 Estimation of glucose

5c.6 Estimation of blood urea nitrogen

5c.7 Estimation of Uric Acid in serum

5c.8 Determination of barbiturates

5c.9 Estimation of serum alkaline phosphatase

5c.10 Immunoassay

5c.10.1 Principles of Radio Immunoassay (RIA)

5c.11 Blood gas analysis

5c.12 Trace Elements in the body

5d Drug Analysis

5d.1 Narcotics and dangerous drugs

5d.2 Classification of drugs

5d.3 Screening of drugs by gas and thin-layer

chromatography and spectrophotometric

measurements.

5c.3.1 Spectrophotometric determination

5c.3.2 TLC determination

5c.3.3 Gas Chromatographic determination

5.2 Let us sum up

5.3 Check your progress : The Key

5.4 References

5.5 Activity

UNIT-V

ANALYSIS OF SOIL FUEL, BODY FLUIDS AND

DRUGS

5.0 Introduction

Soil, fuel, body fluids and drugs are non-separable parts of human-beings &

their livlihood since time immortal. Without body fluids existence of human body is

not feasible. Soil forms the base upon which we live. Food we eat is produced on the

soil. Fuels are the need for cooking our food, for providing energy to us, for the

transportation, for generating electricity. Fuels are needed to heat boilers for the

industries. Drugs cure ailments occurring in body. Studies in these fields are a must.

5.1 Objective

Clinical analysis are needs to check proper functioning of body. Any imbalance

in the proportion of constituents of body fluids leads to abnormal condition called

disease. Therefore, analysis of total blood, plasma and serum is need for the

diagnosis of diseases. Soil analysis should be done to make up deficiencies of soil to

increase productivity. Fuel analysis helps us to chose good fuel & is needed for

safety needs.

Drugs analysis of synthetic as well as natural drugs helps us to chose proper

drug for disease. Analysis of natural drugs leads to way for the discovery of new and

safer drugs.

Taking into consideration importance of soil, fuels and drugs as well as body

fluid constinents, their study and analysis is essential, which will form subject matter

of this unit-V, i.e. will be the objective of our study.

5a. Analysis of soil

5a.1 Introduction

Soil is as much essential as the food. We draw our food either from plants or

from animals. Plants grow in soil, and animals also depend upon plants and

indirectly draw their food from soil. Main components of soil are moisture, nitrogen,

phosphorus, silica, lime, magnesia, manganese, sulphur and alkali metal salts etc.

Thus soil may be acidic or basic. A brief study of origin of soil may reveal its

components, therefore, its composition. Before proceeding to analysis of soil a

conceise study of soil & hence its composition will be useful.

Formation of Soil

Soil might have formed mainly by three important process occurring in rocks :

1. Physical weathering

2. Chemical weathering

3. Biological weathering

1. Physical Weathering

Physical weathering i.e. disintegration of soil exerts mechanical effect on the

rocks as a result of which rock might have broken down into particles of smaller size.

Physical weathering does not bring any chemical transformation of rock minerals.

This process occurs in deserts, at high altitudes, high latitudes and in topographic

relief as well as the rocks where vegetation is poor. The temperature, water, ice,

gravity and winds are some climatic factors responsible for physical weathering. e.g.

temperature may bring about the break down of heterogenous rocks. Water may be

responsible for mechanical weathering of rocks by rain water. Freezing and melting

of ice causes weathering of rocks by frost action and glacier formation.

Landslides and rock slippages due to earthquake fall in the category of

gravitational weathering where rocks are disintegrated by abrasion and forces of

impact. Stromy winds carry suspended sand particles & may cause abrasion of

exposed rocks.

2. Chemical Weathering

Exposed rocks undergo chemical weathering which causes chemical

decomposition or transformation of parent mineral into new mineral or secondary

minerals. For instance, chemical weathering converts Feldspar (Primary mineral of

aluminium and silicon) into clay (a secondary mineral). It is worth noting that

chemical weathering is not effective in deserts as moisture and air are essential for

chemical weathering. Few processes involved in chemical weathering are delineated

below :

(i) Formation of solution

Water soluble minerals like lime stone and gypsum etc., get weathered by the

solvent action of water which is enhanced in presence of CO2 and organic acids.

Later come into existence by the decay of organic remains of animals and plants.

Solutions of these minerals are either absorbed on the surface of negatively charged

colloidal particles or are removed by leaching.

(ii) Hydrolysis

Hydrolysis involves chemical action of water over strong bases and produces

hydroxides of iron, aluminium, magnesium & calcium etc. e.g.

K2Al2Si6O16+CO2+2H2O 4SiO2+Al2O3.2SiO2.2H2O+K2CO3

Primary Mineral Kaolin (Sec. clay mineral)

Hydrolysis releases Na, K, Ca, Mg and silicates into the solution. These are

responsible for the growth of plants.

(iii) Carbonation

Carbonation involves the combination of CO2 and H2O to carbonic acid which

combines with hydroxides of Ca & Mg as well as other minerals of rocks leading to

the formation of carbonates and bicarbonates. e.g.

CO2 + H2O H2CO3

Ca (OH)2 + CO2 CaCO3 + H2O

CaCO3 + H2O + CO2 Ca (HCO3)2

(iv) Oxidation

Oxidation involves reaction of minerals with oxygen leading to the formation

of oxides which get dissolved in water & weaken the rock. This process bring about

the weathering of rock e.g.

4 FeO + O2 2 Fe2O3

Oxides and sulphides of iron, manganese and aluminium are easily oxidized and lead

to chemical weathering of rocks.

(v) Reduction

Fe2O3 (red ferric oxide) can be reduced to FeO (grey ferrous oxide).

Reduction generally occurs in deep zones of earth crust.

2Fe2O3 4 FeO + O2

(vi) Hydration

During hydration water gets attached to rock material as water of

crystallization. This process leads to softening as well as increase in volume of

original material. Hydration also lead to weathering.

2 Fe2O3 + 3 H2O 2FeO2.3H2O

3. Biological Weathering

Micro-organisms like bacteria, fungi, protozoa, lichens and mosses transform

rocks into a dynamic system where energy is stored & organic material is

synthesised. This process changes physical structure as well mineral composition of

rocks.

From the process of soil formation it is clear that chief constituents of soil are

moisture, oxides, hydroxides, silicates, lime, salts of magnesium, aluminium, alkali

metals etc. It contains organic compounds & may be rich in nitrogen & sulphur.

Moreover, soil may be acidic as well as basic.

5a.2 Determination of moisture

Methods generally used for the determination of moisture contents in soil are

:

(i) Gravimetric method

(ii) Volumetric method

(iii) Electrical conductivity

(iv) Gamma rays attenuation

(v) Neutron scattering

(vi) Soil moisture tension

(vii) Time domain refractromety

Volumetric and gravimetric methods are simplier and are more popular

methods which are discussed here :

(1) Volumetric Method

Volumetric determination of moisture contents in soil may be done by (i) Soil

core (ii) Bulk density of soil

(i) By Soil-core

Requirements:

(1) Sample tube

(2) Physical balance

(3) Moisture boxes

(4) Drying oven

Procedure:

1. Place the sample of soil in sampling tube whose volume (v) is known.

2. Weigh the sample is moisture box (A).

3. Dry it in oven to constant weigh (B) at 105C and again weigh it.

Calculation:

Moisture percentage 100)(

Vdw

BAMv

Here, dw = density of water

Volume of sampling tube = r2h

r = radius

h = height

N.B.

1. For better results take more than 50 C.C. in size and greater than 200 g of

soil.

2. Analysis of 10 samples/hectare is enough during investigations.

(ii) Bulk-Density Method

Moisture percentage on volume basis (Mv)

= Mw Bd

Mw = Moisture percentage on dry wt basis

Bd = Bulk density of soil (mg/m3)

(2) Gravimetric Method

For gravimetric estimation of moisture content soil sample is kept at 105 is

oven and is dried to constant weight. Difference in weight of moist soil and dry soil

gives wt of moisture.

Formula used:

100

%

soilweightdry

weightinLossmoisture

Requirements:

(1) Sample auger

(2) Physical balance

(3) Moisture cans

(4) Drying electrical oven

(5) Desiccator

(6) Drying agent.

Procedure:

1. Weight the empty moisture can.

2. Transfer about 100 g of sample in the sample can with the help of auger.

3. Close the moisture can immediately to prevent loss of moisture through

evaporation.

4. Weight the moisture can immediately.

5. Remove the caps of moisture can and heat in oven at 105 to constant

weight. It takes about 45 hrs.

Precaution:

After each heating cool the moisture cans in desiccator containing drying

agent.

Observations:

(i) Wt of empty moisture can = X gm

(ii) Wt of moisture can + Moist soil sample = Y gm

(iii) Wt of moisture can + dry soil = Z gm

Calculations:

Moisture contents in soil = Y - Z

Wt of dry soil = Z - X

100)(

)(

XZ

ZYmoistureofPercentage

Result:

Soil sample under investigation contains _______ % of moisture.

5a.3 "pH Measurement"

pH is negative logarithm of hydrogen ion concentration.

pH =-log [H+]

pH of soil ranges from 0 to 14 accordingly soil may be acidic or alkaline. Soil

with pH 1 to 7 is acidic, with exact 7 is neutral and soil with pH range 7 to 14 is

alkaline. Word pH derives it origin from French word" pouvoir hydrogen" mean

hydrogen power. pH of soil provides important information about properties of soil.

It affects solubility of soil as well as plant growth as later depends upon activity of

micro-organisms. Nitrogen fixing bacteria of soil responsible for growth of legumes

are not very active in acidic soil. Bacteria causing decomposition of organic matter

of soil are ineffective in strong acidic medium. However, fungi survive in acidic

medium.

Soil of pH range 4-5 have toxic concentrations of manganese and aluminium.

Tea, blue berries, Green berries, few confers as well as rhododandrons grow is

strongly acidic soil. But beans, alfa, beets and barley grow in slightly acidic to

moderately basic soil on account of high calcium demand and little tolerance of

aluminium. Minerals are soluble in acidic soil as compared to basic or neutral soil.

Measurement of pH

Two important methods for determination of pH of soil are :

(1) pH - meter method

(2) Colorimetric method

(1) is generally used.

pH-Meter Method

For measuring pH of soil pH meter used which is a glass electrode pH meter

with calomel reference electrode with salt-bridge. Modern digital pH meters are

single electrode pH meters which require calibration before use with buffer solutions

of known pH. A glass surface in contact of H+ ions pH of which is to be measured

acquires an electrical potential & gives H+ ion concentration i.e. pH of solution.

Requirements:

(i) Glass electrode pH-meter

(ii) Beaker

(iii) Glass rod

(iv) Distilled water (D.W.)

(v) Standard buffer solution

Preparation of buffer solutions of standard pH

These solutions may be of pH 4.0, 7.0 or 9.2 in distilled water. To prepare

them tablet available in market may be used. A single Tablet is dissolved in double

distilled water and volume is make up to 100ml. In case, standard buffer is not

available saturated solution of potassium hydrogen tartarate (A.R.) may be used

which gives a pH of 3.6 at 25C.

Determination of pH of soil:

pH of soil can be determined in three forms of soil solutions:

(i) pH in Saturated Soil Paste

1. Prepare the paste of the soil in small amount of distilled water in a beaker

with the help of a spatula.

2. A saturated paste glisters & flows upon tilting the beaker.

3. After preparing saturated paste cover it & allow it to stand for approximately

four hours.

4. Now there should be no free water on the surface of soil and the paste should

not stick or loose its glistening. From this paste pH can be determined.

5. If soil loses it shinning more soil may be mixed to paste.

(ii) pH in 1:2 Soil Water Suspension

1:2 soil-water suspension may be prepared by adding 80 ml of distilled water

to 40g of soil in 250ml Erlenmeyer flask & mixing the contents on reciprocating

shaker for 1 hr. During the process as well as after preparing the suspension flask

should be stoppered.

(iii) pH in 1:2 Soil and Calcium Chloride Solution Suspension

1. Place 20g of air dry soil in a 100 ml beaker.

2. Add 40 ml of 0.01 M-CaCl2 solution to it. CaCl2 solution can be prepared by

dissolving 14.7g CaCl2.2H2O in 10 litre water. pH of this solution must be

checked which should be between 5.0-6.5. This pH may adjusted with Ca

(OH)2 or HCl.

3. Now leave the contents so that CaCl2 solution get absorbed by the soil. It is

worth mentioning do not stir the contents during absorption process. But

after the absorption has taken place stir thoroughly for 10 seconds with the

help of glass rod.

4. Do further stirring four or five times after 5 minutes gaps.

5. Allow the suspension to settle down for 30 minutes.

Procedure:

1. Place saturated solution of soil or 1:2 soil-water or soil-CaCl2 suspension in a

beaker or conical flask.

2. Set the temperature compensating knob of pH-meter and also ensure if the

electrode is completely filled with saturated KCl solution. Let the pH-meter to

warm for 15 minutes so that asymmetric potential of instrument get

eliminated.

3. Take standard buffer solution say that of a pH of 7 in a beaker & immerse

both the electrodes or one electrode in case of combined electrode into the

buffer solution. With the help of knob adjust instrument reading at the pH of

buffer (7 in this case). Now remove the buffer & wash the electrode

thoroughly & carefully with distilled water. Similarly, adjust the pH-meter at

the other pH say that of 9.2. After adjusting pH-meter at 9.2 again electrode

is washed well with distilled water.

4. Now read the pH of soil paste or 1:2 soil-water or 1:2 soil-CaCl2 suspension

with the pH - meter calibrated between 7.0 and 9.2 in step-3.

5. After step-4 again electrodes/electrode are washed with distilled water & then

immersed in distilled water. To maintain electrodes in working condition they

should be kept immersed in distilled water.

5a.4 "Analysis of Total Nitrogen"

Nitrogen is major plant nutrient of soil and is >90%. It exists in soil as

ammonium, nitrate as well as in organic matter and is essential for plant growth.

Total nitrogen of soil can be determined by Autoanalyzer.

Theory:

Soil sample is first digested with H2SO4 so that organic nitrogen get converted

in NH+4 ions. N-N and N-O nitrogen can't be converted completely by Kjeldhahl

digestion. However, in soil very little nitrogen is in this form. But, it contains nitrities

and nitrates.

Requirements:

1. Digestion block [20- place block digester with tractor auto temperature

controller].

2. A 250 ml digestion tube [295 x 40 mm in dimeter].

3. Conc. H2SO4[18M], 96%.

4. Kjeltab : Each tablet contains 3.5g K2SO4 and 0.4 g CuSO4.5H2O.

Procedure:

1. Place ~ 2g of mineral soil with low content of nitrogen (60 mesh) into

digestion tube after accurate weighing and add 10 ml. of conc. H2SO4 with

shaking.

2. Now heat the digestion tube in digestion block until very black [for about 30

minutes]. Digestion block should be loaded in fume-cupboard to avoid

irritation.

3. Add one Kjeltab to the contents. Heat till Kjeltab dissolves at 200C which

takes about 15 minutes.

4. Increase the temperature to 300C and heat for 30 minutes.

5. Now, let the temperature rise to 375C and continue heating till sample turns

turquoise which may take upto 45 minutes.

6. Take out digestion tube from block and allow to cool for 5 minutes. Cooling

should not be done in heating block, because ammonia formed from

ammonium sulphate formed during the digestion may be lost by the action of

heat.

7. Mix the sample with 50 ml of water till sample goes into the solution.

8. Analyse as per the instructions of analyser.

Alternative Method

In Kjeltc Auto 1030 Analyses method ammonia liberated by the distillation of

digest with strong alkali is absorbed in unstandardized H3BO3 to get Ammonium

borate. Borate is titrated back to H3BO3 by titration against standard acid (HCl).

Requirements:

1. Kjeltec Auto 1030 Analyser

2. Distillation apparatus

3. Titration Apparatus

4. 40% NaOH; 10g NaOH in .25 litre H2O

5. H3BO3 solution : 100g H3BO3 is 10 litre water.

6. Receiving Solution : To above H3BO3 solution add 10 ml

Bromocresol solution (100g in 100 ml CH3OH). Add 70ml methyl red to it

(100mg in 100 ml CH3OH). To this solution also add 5 ml of 4% NaOH.

7. Standard HCl (0.01m).

Procedure:

1. Make up digest to 100ml

2. Follow instructions of operation of Kjeltc 1030 Analyser.

3. Set Alkali pump to deliver 30ml of 40% NaOH.

4. Titrate with 0.01M-HCl

Calculations:

% of nitrogen in sample =

)(

tandard )(401.1

gsampledryovenofWeight

HClsofMolarityBT

Here,

T = Total Volume (ml) of standard HCl

used for the titration of sample

B = Standard HCl for titration in blank (ml)

Check your progress-I

Notes:

(a) Write your answer in the space give below.

(b) Compare your answer with those given at the end of the unit.

(i) Can moisture in soil be determined gravimetrically.

(ii) pH of acidic soil is 10. Ture/False.

(iii) To make the soil basic _____________ is added.

(i) _________________________________________________

(ii) _______________________________________________

(iii) _________________________________________________

5a.5 "Analysis of PHOSPHORUS"

Phosphorus is present in the soil to the extent of 0.01 to 0.3% and is present

in different forms. Primary minerals of apatite group are the original source of soil

phosphorus. It is found as hydroxy-phosphate of Fe, Al, Ca, Mg, Mn and Ti.

Phosphates of Ca, Fe and Al are most important quantitatively. Out of total soil

phosphorus only a little amount is available to plants. Out of various chemical

methods available to determine available P Olsen method is most important.

Olsen's Methods

In this method NaHCO3 of pH 8.5 is used as an extractant. Reaction between

phosphate and ammonium molybodate is the basis of this method:

H3PO4+12H2MoO4 H3P (MO3O10)4 + H2O

Molybdophosphoric acid [H3P(Mo3O10)4] formed by the reaction of phosphate and

ammonium molybdate is then reduced to blue coloured complex through the

reaction with ascorbic acid. Now, absorbance is recorded at 730 nm on a

spectrophotometer. A standard curve prepared by using standard solutions is used

to determine concentration of phosphates in the sample.

Requirements:

(i) 0.5 M NaHCO3 solution (Extracting solution)

To prepare it dissolve 42 g of NaHCO3 in 1 litre of distilled water (D.W.) and

adjust the pH at 8.5 with 1M- NaOH solution.

(ii) Dacro G-60 or equivalent grade phosphorus free Charcoal

80 g of Dacro G-60 or phosphosrous free Charcol is used to prepare slurry in

D.W. It is kept overnight in 1 lt. of 6 M- HCl in 60 mm diameter columns (250ml

capacity) and then deionized water is added to it till leachate is free from chloride.

Then, these contents are dried at 110C.

(iii) Ammonium Molybdate Solution

Prepare it dissolve 40g of ammonium molybdate in 1 lt. of D.W.

(iv) Ascorbic Acid Solution

Dissolve 26.4g of L-ascorbic acid in 500 ml of D.W.

(v) Sulphuric Acid (2.5M)

Add 140 ml of conc. H2SO4 in 1000 ml of D.W.

(vi) Antimony Potassium Tartrate Solution

Dissolve 1.454 g of Antimony potassium tartrate in 500ml D.W.

(vii) Murphy-Riley Developing Solution

To prepare it mix 75ml Ammonium molybdate solution, 250 ml of 2.5M

H2SO4, 50 ml L-ascorbic acid solution and 25 ml of antimony potassium tartrate in

100 ml D.W.

(viii) p-Nitrophenol Indicator

(ix) Standard solution of Phosphorus [Stock solution]

Dissolve 0.439gm of KH2PO4 in 500ml D.W.; and 25 ml of 7 N-H2SO4 to it and

make up the volume to 1 lt. with D.W. This solution is 100 ppm stock solution of

phosphorus 5ml of it are diluted to 100 ml in volumetric flask to get 5 ppm

phosphrous solution.

(x) Spectrophotometer.

Procedure:

1. Take 2.5 gm accurately weighted air-dried soil sample in 125 ml flask.

2. Add to it a little phosphorus free Darco G-60.

3. Now add 50 ml of NaHCO3 solution at 25C and shake the contents for 30

minutes.

4. Now apply steps 1-3 to blank [without soil].

5. Filter the extract through whatman 42 or 40 filter paper.

6. Pipette out 10 ml of aliquot in 50 ml volumetric flaks & add 10 ml of D.W. to it

followed by 1 drop of p-nitrophenol indicator. Acidify contents to the pH 5.0

using 2.5 M-H2SO4 drop by drop till colour disappears.

7. Add 8 ml Murphy - Riley solution & make up the volume to 50 ml with D.W.

Now, keep the contents form 15 minutes at R.T. & record the absorbance of

blue coloured solution on spectrophotometer or colorimeter at 730 mm.

Calculations:

Wt of soil sample = 2.5 g

Volume of NaHCO3 extractant added = 50 ml.

Vol. of extract taken to develop colour = 1o ml.

Reading of colorimeter or spectrophotometer = X

Concentration of phosphorus in 50 ml extract

= C/10g/ml.

In 1 g of soil concentration of phosphorus

mlgC /5.2

50

10

Hence, available phosphorus in Kg/ha

24.25.2

50

10

C

= C 4.48 ppm in Kg/ha.

or Available soilofwt

aliquoltextracofvolCp

24.2/tan .

Here, C = g P in aliquots (obtained from curve)

Preparation of Standard Curve :

For the preparation of standard curve take 1, 2, 3, 4 and 5 ml of 5 ppm

solution in 50 ml of volumetric flasks & making up the volume. Record the

absorbance on colorimeter or spectrophotometer as given in procedure above.

Prepare standard curve by plotting absorbance Vs concentration of phosphorus in

standards.

5a.6 "Analysis of Silica"

It is reported that silicon contents enhance length and number of stems of

rice plants as well as their fresh and dry weights. Perhaps they also increase

productivity of barely and cucumber. Silicon is second most important element and is

present in most of the minerals. Soil contain large number of silicates. Gram and to

some extent other plants also contain silicon. Analysis of total silicon contents

involves following steps.

1. Digest soil with perchloric and nitric acids followed by heating for 15 minutes.

2. Dilute the digest and filter silica through whatmann no. 41 filter paper. Wash

it with warm and dil HCl (1:20) as well as with D.W.

3. Evaporate the filtrate [containing washings as well] to dryness and heat the

residuce at 110C for an hour. This step recovers small amount of silicic acid

present in solution.

4. Now extract the residue with dil HCl, filter and wash as given as step 2.

5. Ignite the combined residue along with filter paper in a weighed platinum

crucible in muffle furnace till constant weight and find out the weight of Crude

silica. From the weight of silica amount of Si present in soil can be determined

by multiplying with the factor 0.4672.

Analysis of water soluble Silicon : Quantity of water soluble silicon in soil

can be determined by molybdenum blue method.

Requirements:

1. Standard silicon solution

2. 10% W/v ammonium molybdate solution

3. 0.25 M-HCl

4. Na2SO3 solution containing 17g dm 3 Anh. Na2SO3.

5. Citric acid.

Procedure:

1. Extract soluble Si from soil with water and filter.

2. Pipette out 25 ml of clear filtrate in 15 ml conical flask and add to it 15 ml of

dil HCl.

3. Add 15 ml of ammonium molybdate solution after 6 minutes to the contents

of flask followed by 2 ml of citric acid & 25 ml of Na2SO3 solution.

4. Mix the contents well and record optical durity (O.D.) at 650 mm exactly 1

minutes after adding reductant.

5. Standard curve needed to estimate Si can be prepared to cover the range 0-5

g/ml of Silicon.

5a.7 "Analysis of Lime"

Lime increases pH of soil. Optimum degree of soil acidity requirements vary

from crop to crop. Lime in soil increases supply calcium to plants. Lime requirement

of soil can be determined by shoe maker method (also known as Buffer method).

Shoe Maker Method

Requirements:

(i) p-Nitrophenol - 1.8 g

(ii) Triethanol amine - 2.5 ml

(iii) K2CrO4 - 3.0 g

(iv) (CH3COO)2Ca - 2.0 g

(v) CaCl2.2H2O - 40.0 g

To prepare Buffer dissolve above salts in 800 ml of D.W. and adjust pH at 7.5

with the help of dil HCl or NaOH solution. Dilute it to 1 litre with D.W.

Procedure:

1. Add 10 g of soil to 20 ml of above Buffer and mix well for 10 minutes by

stirring.

2. Record pH of suspension and determine lime requirement of soil from

observed decrease in pH of Buffer using curve prepared from the data of

shoemaker. For the initial quantity of soil taken as 50g divide the result by 5.

5a.8 "Analysis of Magnesium"

Magnesium can be titrated with EDTA using Eriochrome black T dye as

indicator at pH-10 in presence of NH4Cl and NH4OH buffer. Completion of titration is

indicated by the change of colour from wine red to blue or green.

Requirements:

(i) EDTA - 0.01 N.

(ii) NH4Cl - NH4OH buffer : To prepare it dissolve 67.5 g NH4Cl in 570 ml of conc.

NH3 and make up the volume to 1 lt.

(iii) Eriochrome black T indicator

(iv) 2% NaCN solution.

(v) Carbamate

Procedure:

1. Pipette out in a 150 ml conical flask 25 ml aliquot containing not more than

0.1 ml of Ca+ Mg. If solution in more concentrated it should be diluted.

2. Add 2-5 Crystals of Carbamate & 5 ml NH4Cl - NH4OH buffer 3-4 drops of

Eriochrome black - T indicator.

3. Titrate the solution in conical flask with 0.01N EDTA till colour charges from

wine red to blue or green.

Calculations:

If N1 & V1 are normality and volume of aliquot taken and N2 & V2 are

normality & volume of EDTA used.

Then,

N1V1 = N2V2

1

221

N

VNN

or tkaenaliquotofVolume

EDTAofNormalityEDTAofVolumeN

1

N1 = Normality = equivalent of Ca2+ + Mg2+ in one lt.

Milli equivalents of Ca2+ + Mg2+/lt.

tkaenaliquotofVolume

EDTAofVolEDTAofVolume

1000 .

Milli equivalents (Me) of Mg2+

=Me[Ca2+ + Mg2+] - Me of Ca2+ + Mg2+ g/lt.

Normality of EDTA vol. of EDTA Eq. wt. of Ca2+ + Mg2+

=

Vol. of aliquot (ml) taken

Since , Me/lt. eq. wt. / 100 = g/ lt

g/lt of Mg2+ = g/lt of Ca2+ + Mg2+ - g/lt of Ca2+

Importance of Mg:

Mg is known as secondary micronutrient for plant growth & is required from

the beginning in small amount. It is found dissolved in water as soluble salts. Mg is

integral part of chlorophyll and is also involved in enzymatic reactions. It helps to

increase vitamin, sugar, starch and insulin in root crops. Its deficiency causes

chlorosis.

5a.9 "Analysis of manganese (Mn)"

Mn is micronutrient and is determined by using DTPA (Diethylene Triamine

Pantaacetic Acid) which is a chelating agent for the combination of free metal ion

present is pollution.

Requirements (Apparatus)

(i) 100 ml capacity narrow mouth polyethylene stopped bottles.

(ii) 20 ml pipette

(iii) Reciprocating electric shaker.

(iv) Whatman No. 1 or No. 42 Filter paper.

(v) Funnels.

(vi) Atomic Absorption Spectrophotometer (AAS)

(vii) Hollow cathode lamp of Mn.

(viii) Analytical balance.

Reagents Required:

(i) Extracting Solution

0.005 -M DTPA + 0.01-M CaCl2.2H2O+ 0.1 M TEA (Triethamol amine with pH

= 7.3)

(ii) Stock Solution

Standard stock solution should be prepared by dissolving 0.1 g foil or wire of

Mn in dil HCl (1:1) and making up the volume to 1 lt.

(iii) Working Standard Solutions

These are prepared by transferring 0, 1, 2, 3, 4, 6 and 8 ml of strock solution

to 100 ml volumetric flask and diluting each to mark with DTPA extracting solution.

These solutions contain 0, 1, 2, 3, 4, 6, & 8 g/ml (ppm).

Procedure:

1. Weigh 10 g air dried soil sample.

2. Transfer it to 100 ml narrow mouth Polyethylene bottle or conical flask Add

20 ml DTPA solution.

3. Stopper them & shake at 25C for 2 hrs.

4. Filter the contents through whatman No. 1 or No. - 41 filter paper.

5. Filtrate is used for analysis.

6. Keep a blank (without soil) for analysis also.

7. Set zero of instrument with blank.

8. Place standards in AAS to standardize it and read absorbance.

9. Feed DTPA extract & record absorbance or concentration of Mn.

10. Repeat above steps.

Calculations:

Wt of soil taken = 10 g.

Vol of DTPA solution added = 20 ml.

Dilution = 2 times.

Absorbance shown by AAS = A.

Concentration of micro nutrient (Mn) read from standard curve against Absorbance A

= C.

Mn is soil sample = C 2 mg/kg or ppm or g/ml.

N.B. Standard curve is drawn between readings of absorbance & concentrations of

Mn in ppm on graph paper.

Importance of Mn

It is a constituent of enzyme & is involved in protein synthesis. It increases

translocation of sugars through stems and leaves of cotton plant to improve the fibre

strength of cotton. Mn also favours the accumulation of ascorbic acid in grape leaves

and of sugar in grapes. Excess of Mn leads to chlorosis and nacrosis of leaves.

5a.10 Analysis of Sulphur

For the determination of S, heat soluble sulphur, 0.15% CaCl2 extractable

sulphur and phosphate extractable sulphur methods are used. Heat soluble sulphur

method is more common.

Requirements:

(i) 1% NaCl solution

(ii) BaCl2.2H2O solution : 20-30 mesh crystals.

(iii) Stablizing Solution : 75 g Nacl, 30 ml Conc. HCl, 100 ml absolute alcohol,

50 ml glycerol and 250 ml D.W.

(iv) Standard Sulphate Solutions : 1.080 g K2SO4 dissolved in D.W. and made

up the volume to 100 ml.

(v) 3% H2O2.

Procedure:

1. Place 5.0 g accurately weighed soil in a silica basin and add 20 ml D.W. to it.

2. Keep the basin in gently boiling water and evaporate to dryness. Then, heat it

in hot air oven at 102C for 60 minutes.

3. Cool the contents and transfer the soil in 50 ml centrifuge tube. Extract it with

33 ml of 1.0% NaCl solution.

4. Pipette out 25 ml of aliquot in silica basin and evaporate to dryness with 2 ml

of 3% H2O2. Again heat it in hot-air oven at 102C for 60 minutes.

5. Cool the residue and add to it 25 ml D.W., transfer again to centrifuge tube

and centrifuge to remove suspended particles. From this aliquot sulphur is

determined.

6. Place 10 ml aliquot in 250 ml flask and add to it 20 ml D.W.

7. Now, add 2.5 ml stabilizing solution, 0.2 g BaCl2 crystals by a spatula to the

standard and extract. Shake the flask for 1-minute.

8. After about 3 minutes measure the turbidity in colorimeter using blue filter or

in spectrophotometer at 340 nm.

9. Prepare standard curve by plotting absorbance of standard solutions against

their concentrations and read the concentration corresponding to absorbance

of soil sample.

Calculations:

SO4 - S mg/Kg

soildayovenofWtaliquotofVol

extractofvolumealiquotinlmgS

.

)/(

Estimation of S by Colorimetic Method

[Palaskar et al. (1981) method]

In this method S is extracted in 0.15% CaCl2.2H2O solution in 1:5 soil to

solution ratio. 10-20 g of soil is used and mixture is shaken for 30 minutes. S is

estimated in 5-10 ml aliquot obtained by extract filtered through whatmann No. 42

filter paper. Requirement from p-36 of original.

Procedure:

1. Pipette out 5 ml of 0.1 N Barium chromate in 150 ml volumetric flask. Add 1.2

ml 5N-NH4OH to it which reduces free acidity to 0.05N. This solution should

be clear.

2. Aliquot of soil extract is added to it to keep SO4-S content below 2000 g.

Shake the contents and keep for half an hour.

3. Now add 1 ml NH4OH to precipitate unreacted barium chromate & make upto

100ml with D.W.

4. Stopper the flask and make upside down 3-4 times. Filter the contents

through whatmann - 42 filter paper. Reject first few ml fitrate.

5. Record absorbance of yellow solution in colorimeter using deep blue (420

mm) filter and determine concentration of S using standard curve.

N.B.

1. pH of test solute should be around 2-3 before addition of Ba-chromate. If

solution is alkaline it should be adjusted with 6N-HCl.

2. For the preparation of standard curve 0, 4, 8, 16 and 20 ml of 100 ppm

solution of SO4-S is made up to 100 ml in volumetric flasks with D.W. These

solutions have 0, 4, 8, 16 and 20 ppm S concentrations. Color intensity of

these solutions is recorded on photoelectric colorimeter using deep blue (420

mm) filters and intensity of blank is also recorded. Intensties are plotted Vs

concentration and concentration of sulphur is determined.

Important Information

S is present in soil in both organic as well as inorganic forms, but only a

fraction is available to plants. Inorganic sulphur is in the form of SO4--.

5a.11. Analysis of Alkali-Salts

Alkali salts make the soil saline or alkaline. In aqueous solution they are

present in their ionic concentrations. Water soluble alkal-salts are determined in Soil

by:

(1) Saturation extracts

(2) 1 : 2 soil water extracts.

(1) Saturation Extract Method

Procedure:

1. Weigh 200-400 g of soil accurately.

2. Take it in weighed flask and add sufficient D.W. to it with mixing to prepare

saturated solution.

3. Allow to stand for 4 hrs. If soil has stiffness and does not glistens, add more

D.W. and mix well.

4. Weigh the container and contents. Record increases in weight which

corresponds to amount of water added.

5. Calculate the saturation percentage (SP) gravimetrically.

100

soilofwtdayOven

PasteSoilSaturatedofcontentWaterSP

6. Now transfer the soil to Buchner funnel with highly retentive filter paper &

collect the extract - by applying vacuum till air passes through filter. Add one

drop of 1.0% (NaPO3)6 solution per 25 ml of extract to check the precipitation

of CaCO3.

7. Store the extract at 4C till it is analysed.

(2) 1:2 Soil-Water Extract Method

Procedure:

1. Weight 25 g of soil in `100ml beaker.

2. Add 50 ml D.W. to it & shake on shaker for 30 minutes.

3. Filter the suspension through whatman No. 1- filter paper & collect the

filtrate.

4. This filtrate is used for the determination of alkali metal salts.

N.B.

(1) The cations [Ca2+, Mg2+, Na+, K+] are normally determined by compleximetric

titration, AAS or atomic emission spectrometric methods.

(2) Primary anions in soil extracts are normally SO42-, CO2

-2, Cl-, NO3- and HCO3

-.

These are determined by titrimetric or Atomic emission spectrometric

methods.

Check your progress-II

Notes:

(a) Write your answer in the space give below.

(b) Compare your answer with those given at the end of the unit.

(i) Can moisture in soil be determined gravimetrically.

(ii) pH of acidic soil is 10. Ture/False.

(iii) To make the soil basic _____________ is added.

(i) _________________________________________________

(ii) _________________________________________________

(iii) _________________________________________________

5b. "FUEL-ANALYSIS"

5b.1 Solid, Liquid and Gaseous Fuels

The materials which when burnt produce heat energy are known as fuels. For

instance; Coal, charcoal, wood, LPG, Kerosene, petrol and diesel etc. Fuels are

concentrated store houses of energy which is released as heat when fuels are burnt.

They are infact, most important sources of energy in daily life; for example, in

homes, transport and industry. Important uses of fuels are:

1. In homes for cooking & other heating purpose. Fuels like LPG, Wood, Coal,

Kerosene, Cow-dung & Charcoal etc., are used for this purpose.

2. For transporting men and material from are place to other through motor

cars, trains and aeroplanes etc. Petrol and diesel are used for this purpose.

3. Fuels used in industry are coal, fuel oil or natural gas which are used for

heating the boilers.

4. For generating electricity coal or natural gas are used in thermal power

plants.

5. In rockets used for exploring space: Special fuels known as propellants are

the fuels for this purpose. For instance, synthetic rubber and liquid hydrogen

are rocket fuels.

Most of the fuels are carbon compounds containing hydrogen. Therefore,

when a fuel is burnt, it combines with O2 of air and produces CO2, water vapours

and a lot of heat. Some fuels like Coke and Charcoal are mainly carbon. Three main

sources of natural fuels are; coal, petroleum and natural gas.

Classification of Fuels

Fuels can be classified in following ways.

1. As solid, liquid and gaseous fuels.

2. As natural or raw fuels and manufactured or processed fuels.

3. As Primary and secondary fuels.

(I) Classification of Fuelss as Solid, liquid & Gases

This classification is based on physical state. Examples of each are:-

Wood

Coal

Coke

1. Solid Fuels Charcoal

Paraffin Wax

Kerosene

Petrol

Diesel

2. Liquid Fuels Alcohol

Liquid hydrogen

Liquid fuels

Natural gas

LPG

Coal gas

3. Gaseous Fuels Producer gas

Gobar gas

Acetylene

Hydrogen gas

Other gaseous fuels

Merits of Liquid & Gaseous fuels over solid fuels

1. No residue is left after burning liquid & gaseous fuels, but solids leave behind

ash.

2. Liquid and gaseous fuels can be transported through pipe - lines.

3. Ignition temperatures of gaseous and liquid fuels are low, therefore, they

burn easily as compared to solid fuels.

4. Liquid & solid fuels have high calorific values, hence, produce more heat on

burning than equal amounts of solid fuels.

5. Liquid and gaseous fuel produce no or little smoke.

6. Handling of liquid and gaseous fuels is easier than solid fuel. For instance, it is

easier to handle kerosene than coal.

(II) Classification of Fuels as Natural or Raw Fuels and Manufactured or

Processed Fuels

Fuels that are used in the same form as they occur in nature are called

natural fuels or raw fuels. e.g., Wood, Coal, natural gas, petroleum,

animal drug and agricultural wastes.

On the other hand, fuels which are prepared by natural fuels by various

physical and chemical processes are known as manufactured or processed

fuels e.g. fuels like charcoal, coke, petrol, diesel, kerosene, coal gas, producer

gas & water gas etc. Charcoal is prepared by heating natural fuel wood by

heating in absence of air.

(III) Classification of Fuels as Primary Fuels and Secondary Fuels:

Fuels which are used directly to produce heat are known as primary fuels

e.g., Wood, Coal, Petroleum, natural gas, agricultural wastes etc. Infact,

primary fuels are raw fuels.

The fuels which are prepared from primary fuels are known as secondary

fuels. Infact, they are processed fuels e.g., producer gas, coal gas and water

gas etc.

Choice of fuel depends upon factors like cost, calorific value, convenience,

side effects like pollution as well as availability. Most of the fuels we use come from

bio-mass and fossils and are known as Bio-mass fuels and fossil fuels,

respectively. It is worthnoting waste materials of living objects (like cattle dung) and

dead parts of living objects (like animals, plants and trees) are Bio-mass. But,

fossils are remains of pre-historic animals or plants, buried under the earth, millions

of years ago.

(i) "Solid Fuels"

Ingredients of solid fuels are to two types: (i) Combustible organic matter

and (ii) Incombustible matter. Combustible organic matter includes carbon,

hydrogen and sulphur; but non-combustible part of solid fuel involve moisture and

minerals like silicates, phosphates, carbonates, sulphides of Ca, Fe, Mg, Al, K etc.

Non-combustible materials of solid fuels are responsible for the formation of ash.

Solid fuels are classified into:

(1) Natural solid fuels.

(2) Artificial solid fuels.

(3) Industrial solid fuels.

(1) Natural Solid Fuels

Some example of natural solid fuels are

Wood

Coal

Lignite

Bagasse

Peat

Natural

Solid

Fuesl

(i) Wood

Wood is the fuel found in plenty in India. It contains cellulose, lignin, resin,

inorganic material and water [to the extent of 60%]. Approximate composition of

dry wood is C=50%, O=35%, N=70%, H=6%, & ash=2% Calorific value of Wood

(dried) varies from 4000 - 6400 BTU/pound. Following products are obtained by the

destructive distillation of dry wood.

Product Percentage by weight

1. Charcoal 23.5%

2. Pyroligneous acid 44.3%

3. Wood tar 5.3%

4. Gases: CO, H2, CH4 and CO2, N2 etc. 26.9%

Dry wood is better fuel on account of its low ignition temperature and low ash

contents.

Advantages of wood as a fuel are:

1. As it gives bright flame, it can be used for burning other fuels.

2. It is easily available.

3. It is suitable for domestic purpose.

4. Wood ash is rich in potassium contents, hence, can be used in agriculture.

5. Because, wood gives smaller amounts of ash and soot it can be used in some

industries like glass, firing of porcelain etc.

Disadvantages of wood as fuel are:

1. High moisture contents keep its calorific value low. So, it is rarely used in

industry.

2. It's smoke is harmful for the health of eyes.

(ii) Coal

Coal is complex mixture of compounds containing carbon, hydrogen, oxygen

and also contain some free carbon. Some nitrogen & sulphur compounds are also f

ound in coal. Coal is found in deep coal mines beneath the surface of earth.

India is rich in coal in states like Bihar, West Bengal, Orissa and Madhya Pradesh.

Jharia and Bokaro are rich coal mines found in Bihar, whereas Ranigang is in west

Bengal. Coal is still an important source of energy in our country, therefore, it is

regarded as backbone of energy sector of our national economy. Coal can be

converted into other sources of energy like : electricity, synthetic petrol, coal gas

etc. It is a rich source of organic compound which can be converted into dyes,

drugs, polymers like fibres, explosives, detergents and paints etc.

Original of Coal

It is thought that coal was formed millions of year ago by the decomposition

of large land plants and trees buried deep inside earth. Forests might have been

buried under the surface of earth due to Volcanoes and earthquakes etc and in due

course they were covered with sand, clay and water. At high temperature and

pressure and in absence of air inside the earth, wood might have been converted

into coal. This slow chemical process of conversion of wood into coal is

named carbonization. Carbonization is very slow process and may have taken

thousands of years to take place. As carbonization is slow process several

intermediate products of carbonization exit. They are: anthracite, bituminous, lignite

and peat. Anthracite is last step of coal formation. These products differ in

percentage of carbon. Anthracite is richest in carbon.

Type of Coal

Based upon the concentration of carbon following variation of coal are formed

depending upon the extent of carbonization:

Type of Coal Percentage of Carbon

a. Peat 60%

b. Lignite (Soft coal) 70%

c. Bituminous (House hold coal) 80%

d. Anthracite (Hard coal) 90%

(a) Peat

Peat is formed by the gradual decomposition of plant materials under moist

conditions. This is the initial state of transformation during the coal formation. Peat

is jelly like and is brown colored. Calorific value of peat is low (6000-9000 BTU)

hence, it is not of any economical value. In dry peat ash contents are 2.5-6.0%.

Peat is sometimes used as fertilizer as well as packing material. Deposits of peat are

found in England, Scotland, Iceland, Northern Europe, Germany, Sweden & Russia

etc. In India peat reserves are found in Nilgiri Hill, Palani Hills, in west coast of Tamil

Nadu and in Kashmir state. In dry condition composition of peat is

C = 57%

H = 6.1%

O = 34.9%

Non-combustible mass or ballast of peat contains appreciable moisture

contents 60-70%. On destructive distillation, it yields (NH4)2SO4, fuel gas, tar, wax

and hydrocarbon oils.

(b) Lignite (Soft Coal)

It is also known as brown coal and its composition is between peat and

bituminous coal. Lignite is amorphous, fibrous or woody in texture. Moisture

contents are high in it and calorific value is 4000-6000 cals/Kg. It is used to heat

boilers & evaporating pans in industry & homes. Its reserves are in Assam coal field

& Neyveli. Neyvali lignites are compact and are used in thermal power generation

and also in the manufacture of fertilizers. Whereas Rajasthan liginte is less compact

& fibrous. Its non-combustible material (ballast) are high. On exposure to air it

absorbs oxygen readily & ignites spontaneously. Upon carbonization it yields tar,

synthetic petrol by high pressure hydrogenation. It is superior to peat.

(c) Bituminous Coal

Formation of Bituminous Coal is third stage of coalification. Bituminous coal is

of two types:

(i) Sub-bituminous coal (ii) Bituminous coal

(i) Sub-Bituminous Coal

Sub-bituminous coal is also known as black lignite as it is black is colour. Its

calorific value is 7000-15000 BTU. Moisture content of Sub-bituminous coal ranges

from 10-25%. It ignites readily.

(ii) Bituminous Coal

It is hard, black & dense. Bituminous coal is of two types: low volatile coal &

high volatile coal. Fuel ratio of low volatile at coal is < 2. Bituminous coal burns with

yellow smoky flame. High volatile variety have long flames and find use in gas

industry, coal-tar distillation and in the manufacture of glass. Light grade bituminous

coal is known as Super-bituminous coal. Its calorific value range is 12000-15000

BTU. Super-bituminous coal have higher fuel ratio as compared to bituminous coal &

have best heating power among all coals. Bituminous coal can be converted to coke.

(d) Anthracite

Anthracite contains highest percentage of carbon [~ 90%]. It is hard,

compact & black with sub-metallic lusture and is of fossil origin. Anthracite is last

product of carbonization process. It is sulphur-less is low-ash coal & burns with

smokeless flame. Calorific value range of anthracite is 14000-15000 BTU and fuel

ratio is 9.0-10.2. Anthracite is used in metallurgy, in slow combustion stoves as well

as for domestic purpose.

(e) Pulverised Coal

Pulverised coal is obtained after grinding the fossil coal. It burn quickly & its

combustion temperature is very high. Burning capacity of this coal depends upon the

fineness of particles. Pulverised coal has low ignition temperature because of

presence of volatile material in it. The pulverization procedure includes crushing,

drying & grinding of coal.

(iii) Bagasse

Bagasse (the residuce of sugar industry) is used as fuel for generating steam

in the boilers of sugar industry as well as in some other industries like paper.

(2) Artificial Solid Fuels

Artificial fuels are obtained by the processing of natural fuels. Some artificial

solid fuels are describe below :

Briquette

Charcoal Artificial

(a) Briquette

Briquette is compressed fuel. It is prepared from coal, peat, lignite or coke in

presence of binding material like tar-pitch, asphalt pitch or molasses (5-8%) at an

applied pressure of 1800-3000 psi. It is dried to 50% moisture contents & in further

dried by blowing through tubular driers. Briquette is domestic fuel but sometimes is

used in industries also. It's calorific value in 8000 BTU/pound. Brequetting can also

be carried out without binder under a pressure of 12 tonnes or more per square

inch.

(b) Charcoal

Charcoal can be prepared by the destructive distillation of wood or heating

the wood in limited supply of air. It can also be made in Kilns and in India charcoal

is prepared generally by this method. Generally hard wood is carbonised and gas, tar

and aqueous liquors are obtained, in addition to charcoal. Yield of charcoal is 30-

35%. Gases obtained are 20-23%; tar and oil are

5-7%. Aqueous distillate contains acetone, methanol and acetic acid. Charcoal

contain litte volatile matter hence gets easily ignited & burns with non-smoky flame.

It is good fuel containing small amount of sulphur and phosphorus. It is used in

metallurgy as well as for domestic purpose & also for making carbon disulphide. Its

caloric value is 6000-8000 Cals/Kg.

(c) Coke

Coke can be prepared by the destructive distillation of coal in coke-oven at

about 500-750C. Low temperature carbonization produces semicoke with volatile

matter 5-15%. Semicoke is used for domestic purpose as such or after brequtting or

in the form of pulverized coal. High temperature carbonization (900-1400C)

produces hard-metallurgical coke with high mechanical strength but low calorific

value. Best coke contains about 90% carbon and less than 8% ash.

(3) Industrial Solid Fuels

Fuels used in industry are known as industrial fuels. Some of them are:

2. Liquid Fuels

(i) Kerosene

The composition of Kerosene oil is between C10 to C12 hydrocarbons with the

boiling range 170-250C. It is used as a domestic fuel in stoves for cooking and for

lighting purpose in lanterns. Kerosene oil is also used for making gaseous fuel " The

carburetted water gas."

(ii) Petrol

It is also known as gasoline. Petrol is a mixture of C5 to C10 hydrocarbons and

its boiling range is 40C to 170C. Petrol is a fuel for motor cars, motor cycles,

scooters and other light vehicles. Petrol is also a good solvent & is also used in dry-

cleaning as well as in making petrol gas. Its octane No. ranges 60-70.

(iii) Diesel

Diesel is a mixture of C13 to C15 hydrocarbons and its boiling range is 250-

350C. It is a fuel for heavy vehicles like trucks, buses, ships and diesel enzines etc.

Fossil coal

Peat

Feunace Slags

Oil Shales

Metallurgical Coal

Industrial

Fuels

Fossil coal

Peat

Furnace Slags

Oil Shales

Metallurgical Coal

Industrial

Fuels

Diesel is also used to run water pumps for irrigation as well generators which

generate electricity on small scales for houses, agriculture and industry.

(iv) Fuel oil

Fuel oil contains hydrocarbon containing 15-18 carbon atoms. Boiling range of

fuel oil is 350-400C. It is used in furnaces as well as to heat boilers. Advantage of

using oil fuel is that it leaves no residuce.

(v) Alcohol

Power alcohol is used as fuel when blended with petrol in internal combustion

enzymes. Ethanol can't be used as such as a fuel but is used as an additive. Octane

number of alcohol is 95. When alcohol is mixed with petrol it increases its Octane No

by 0.9 unit for percentage volume of alcohol. Therefore, it is blended with petrol by

using blending reagents like benzene, ether and tetralin. Blending can't be done

without blending reagent. Alcohol is blended because of its anti-knocking property &

can be used in enzines with higher compression ratio. However, alcohol reduces

calorific value of petrol.

5b.2 Gaseous Fuels

Some gaseous fuels are :

Gaseous

Fuels

Natural Gas

Producer Gas

Coal gas

Blue Water gas

Semi water gas

Carburetted Water Gas

Ethyene

Aectylene

(i) Natural Gas

Natural gas consists of mainly methane with small quantities of ethane &

propane. It contains about 95% of methane. Natural gas occurs deep under the

crust of earth either alone or alongwith oil above the petroleum deposits. Thus,

some well dug into the earth produce only natural gas while others produce natural

gas as well s petroleum oil. In latter case, natural gas is by-product of petroleum

mining. In India, we have a number of gas fields. Some recent ones are located in

Tripura, Jaisalmer, off-shore area of Bombay and in Krishna Godvani delta. Natural

gas is formed under earth by the decomposition of vegetable matter lying under

water. Decomposition occurs through anaerobic bacteria in absence of oxygen.

Natural gas obtained from oil wells is of two types:

(a) Dry Natural Gas (b) Wet Natural Gas

(a) Dry Natural Gas

It is obtained from the wells which contain no crude petroleum. It is

composition is CH4=96%, C2H6=0.8% and N2=3.2%

(b) Wet Natural Gas

This type of natural gas is obtained from oil wells and contains high boiling

hydrocarbons like n-propane, n-butane, iso-butane and iso-pentane also.

Sometimes helium gas is also found is natural gas. Calorific value of natural

gas ranges 950-1100 BTU/cubic ft. This gas is also formed by the fermentation of

organic matter in sewage which is mixture of : CH4 = 70% & CO2=30% and calorific

value of which is 62.5 BTU/cubic ft. Natural gas obtained by the fermentation of

cow-dung is used as fuel gas also.

Properties of Natural Gas

It buns with smoky flame in ordinary burners & it can be liquified under

pressure & cooling to 121C. Its 200 volumes can be absorbed on 1 Vol. of fuller's

earth at -121C.

Advantages of Natural Gas

1. Natural gas being a complete fuel in itself can be used directly for heating

purposes in home & industries. Nothing needs to be added to it.

2. It is a good quality fuel with high calorific value. It leaves behind no residue &

also burns with smokeless flame. Moreover, gases produced by burning it are

not poisonous.

3. A great advantage of natural gas is that it can be supplied directly from the

gas well to homes and factories for burning through undergrounds pipelines.

This eliminate the need for additional storage and transport.

The construction of pipelines for natural gas was earlier thought to be

expensive, but it is economical in long run. Once, a pipeline has been laid, there is

no need to spend money on the construction of storage tanks for gas or for

transporting the gas by rail or road. Earlier, pipeline for natural gas was constructed

in Baroda city.

Uses of Natural gas

1. It is used as domestic as well as industrial fuel.

2. Natural gas is used as a source of hydrogen needed in fertilizer industry.

Upon heating the natural gas strongly methane present in it decomposes to

give carbon & hydrogen.

24 2HC

heating

Strong

CH

[Present in natural gas]

Hydrogen gas thus obtained in used to prepare ammonia which reacts with

acids to give fertilizers.

5b.2.1

(ii) Producer Gas

Producer gas is a mixture of carbon monoxide and nitrogen. It can be

obtained from low grade coal, hence is a cheaper gas. Wooden wastes, peat, spent

tar bark and other carbonaceous fuel , are used to prepare it; but fuel generally

used are coke and coal. For its preparation restricted supply of air is allowed through

burning solid carbonaceous fuel in a special type of furnace known as producer.

Temperature of the furnace is kept at 1000-1400C. Producer gas obtained from coal

has a calorific value of

145 BTU/cubic ft. Another gas produced with producer gas is semi-water gas.

Combined Manufacture of Producer Gas and Semi-Water Gas

Two types of manufacturing units are used for this purpose:

(i) Pressure type Unit (ii) Suction type unit.

(i) Pressure Type Unit

In pressure plants air is pumped through hot fuel. A steam-air mixture can be

forced through hot fuel bed by steam pressure.

(ii) Suction Type Units

Suction type units are used in case of gas-enzines. Here air is forced by the

strokes of enzine or by the means of suction fan.

Characteristic feature of such as plant are:

1. Pressure type plant has a diameter of 10 feet and its height in 12ft.

2. Plant is made up of steel shell with refraction linking.

3. Fuel is kept on stationary crate at the bottom of shell.

4. Consumption of coal in it is 1500-2000 Kg/hr.

5. In pressure type plant steam- air mixture is forced through fuel with the help

of pipe at the bottom & semi-water gas or producer gas passes out from the

top through outlet pipe.

Composition of producer gas and semi water gases are:

(a) Producer Gas from Coke

CH4 = 0.4%

C2H4 = 0%

H2 = 13.2%

CO = 25.3%

CO2 = 5.4%

N2 = 55.2%

O2 = 0.5%

Calorific value = 137 BTU/cubic ft.

(b) Producer Gas from Coal

CH4 = 2.5%

C2H4 = 0.4%

H2 = 12.0%

CO = 27.0%

CO2 = 2.5%

N2 = 55.2%

O2 = 0.3%

Calorific value = 145 BTU/cubic ft.

(c) Composition of Semi-Water Gas

CH4 = 2.0%

C2H4 = 0.0%

H2 = 34.0%

CO = 27.0%

CO2 = 8.0%

N2 = 29.0%

O2 = 0%

Calorific value = 245 BTU/cubic ft.

Formation of Producer and Semi-Water Gas

1. First CO2 is formed in restricted supply of air.

2C + O2 2CO - 57,000 cals.

C + O2 CO2 - 96,500 cals.

2. At higher temperature CO2 reacts with hot carbon to give carbon monoxide

gas.

C + CO2 2 CO + 38,700 cals.

3. N2 of air remains unaffected.

4. Some H2 and CO are formed by the action of steam and carbon.

C + H2O CO + H2 + 39,900 cals.

5. Some CO2 escapes reduction.

6. Some CH4 and C2H4 are formed by the destructive distillation of coal.

7. For the formation of semi-water gas 7 volumes of air and 1 volume of steam

is passed.

N.B.

(1) Producer gas is mainly a mixture of carbon monoxide & Nitrogen.

[CO + N2]

(2) Temperature of the furnaces is initially 1000C which gradually increases to

1400C.

(3) 1400C temperature is maintained by regulating the supply of air steam

mixture composition.

5b.2.2 Water Gas

Water gas is mainly of two types :

(i) Carburetted water gas

(ii) Blue water Gas

Water gas is mainly mixture of CO gas and H2 gas.

(i) Carburetted Water Gas

Carburetted water gas is produced by mixing oil gas & permanent gases

produced by cracking kerosene oil. Oil gas contains considerasle amount of ethylene.

It's calorific value is 444 BTU/cubic ft. Manufacturing unit for carburetted water gas

consists of :

(a) Generator

(b) Carburetter

(c) Steel cylinder with lining of refractory bricks.

(d) Super heater

(e) Purifiers

(f) Scrubbers

(g) Condensers.

(ii) Blue Water Gas

Water gas is known as blue water gas as it burns with the blue Flame. Blue

water gas can be prepared by passing steam through hot bed of coke at 1000C-

1400C. The reaction is endotheremic, hence temperature falls down from 1400C.

Little carbon dioxide is also formed and its amount becomes considerable at 1000C.

H2O+C CO + H2 + 38,700 Cals.

2H2O + C 2H2 + CO2 - 19,000 Cals.

CO2 has no calorific value, hence it is undesirable. The formation of water gas

depends upon the decomposition of steam by carbon. At 1125C composition of

water gas becomes H2 = 50.7%, CO=48% and CO2 = 1.3% Actually, rate of

decomposition of steam and formation of water gas are maintained by alternate run

and blow periods. As soon as, temperature falls below 1000C, the steam blast is

stopped and an air blast is passed through red hot coke to raise the temperature of

coke to ~14000C. When temperature is reached air blast is stopped & steam blast is

resumed. As air forms explosive mixture with water gas, latter remaining in the

generator is removed by passing steam for one minute. Steam sweeps off water gas

from generator. The steam passed to remove water gas is known as purage steam

(~ 1minute). The period for which air is passed is known as hot blow & for which

steam is passed is called cold blow. Calorific value of blue water gas is 330

BTU/cubic ft.

Compositions of water gas & carburetted water gas are:

CH4 = 0.1%, H2 = 51.5%, CO = 41.0%, CO2 = 4.0%, N2 = 3.4%, and CH4 = 9.0%,

C2H6 = 1.5%, C2H4 = 7.4%, H2 = 37.3%, CO = 34.8%, CO2 = 3.7%, O2 = 0.4%, N2

= 5.9%, respectively.

Check your progress-III

Note:

(a) Write your answer in the space give below.

(b) Compare your answer with those given at the end of the unit.

(i) Gaseous fuel leaves no residue. True/False

(ii) Main constituents of water gas are _____________ .

(iii) What shall happen if diamond is thrown in fire.

(i) _________________________________________________

(ii) _________________________________________________

(iii) ________________________________________________

5b.3 "Analysis of Coal"

[Ultimate and Proximate Analysis]

Coal is formed from animal and plant organic matter which were buried inside

the earth thousands of years ago. As it was formed from organic matter it contains

elements of organic compounds i.e. C, H, N, O and S besides non-combustible

inorganic matter. Quality of coal is assessed by two types of analysis :

1. Ultimate Analysis

2. Proximate Analysis

Ultimate Analysis

Estimation of carbon, hydrogen, nitrogen, sulphur and ash in the coal is

carried out in the ultimate analysis of coal. This analysis is needed to calculate the

heat balances in any process for which coal is used a fuel.

1. Estimation of Carbon and Hydrogen

Approximetely 2.0 gm of accurately weighed coal sample is used for this

purpose. It is burnt in a combustion apparatus which converts C & H into CO2 and

H2O, respectively. CO2 is absorbed in pre-weighed KOH tube & H2O in pre-weighed

anh. CaCl2 tube. Percentage of C & H is calculated from the increase in weight of

absorption tubes.

C + O2 CO2

12 44

H2 + ½ O2 H2O

2 18

2 KOH + CO2 K2 CO3 + H2O

CaCl2 + 7 H2O CaCl2.7H2O

(i) 10044

12

%

takencoalofwt

tubeKOHofwtinIncreaseCofage

(ii) 10018

2

aCl % 2

takencoalofwt

tubeCofwtinIncreaseHofage

2. Estimation of Nitrogen

For the determination of nitrogen in coal 1 gm of coal sample is taken in

Kjeldahl flask alongwith H2SO4, K2SO4 & HgSO4. They are heated to convert

nitrogen into ammonium salt. The sample solution in than made alkaline with NaOH

and liberated ammonia is distilled into definite volume of standard acid solution, in

which it gets absorbed. Unused acid is determined by titration with standard NaOH

solution. From the volume of acid used with ammonia liberated is used to calculate

percentage of nitrogen.

takencoalofwt

acidofNormalityusedacidofVolNitrogenof

4.1 . %

3. Estimation of Sulphur

Sulphur is estimated from the washings of known mass of coal used in Bomb

calorimeter to determine calorific value. Sulphur in washings is converted into

sulphate for which washing are treated with BaCl2 solution and BaSO4 is precipitated.

Precipitate is filtered through whatman filter peke no. 42, ignited & heated to

constant weight.

100233

32

% 4

rcolorimetebombinandcoalofWt

obtainedBaSOofWtsulphurofage

4. Estimation of Ash

For the determination of ash 1-2 gm powered coal is taken in platinum

crucible & are heated carefully on a Bunsen burner. Then lid is removed & strong

heating is done to burn any tarry material. The lid is kept in desiccator. Heating of

the coal in crucible is continued at 800C in muffle furance till coal is completely

burnt leaving behind ash only. Crucible is now cooled is desiccator & weighed to

constant weight.

100 taken

eftsh xygen %

coalofWt

laofWtOofage

5. Estimation of Oxygen

%age of oxygen = 100 - [%age of C+H+N+S+ash]

Results of ultimate analysis of peat and anthracite are given below:

S.

No.

Type of Coal C

%

H

%

O

%

N

%

S

%

Caloric Value

1 Peat 60 06 32 1.5 0.5 8000 BTU/

Pound

2 Anthracite 94 03 02 01 00 15000 BTU/

Pound

2. Proximate Analysis

It records moisture, volatile carbon matter, ash & fixed carbon percent of

original wt of coal sample.

1. Determination of Moisture

1-2 gm of air-dried powder of coal sample is taken in a silica crucible which

has been heated to constant weight. This crucible is then heated in electric oven for

1 hr at 107 2C. Crucible is cooled in desiccator and weighed again. Amount of

weight loss is equal to amount of moisture.

100

%

takencoalofWt

wtinLossmoistureofage

2. Determination of Volatile Carbonaceous Matter

Dried coal left in moisture determination is covered with lid & heated in

Muffle furnace at 925 2C for 7 minutes. Now, crucible is taken out and cooled first

in air, then in desiccator and is weighed again. Loss in weight gives volatile matter.

100

%

takensamplecoalofWt

mattervolatileofremovaltoduewtofLossmattervolatileage

3. Determination of Ash

As given in ultimate analysis.

4. Determination of Fixed Carbon

The residue left behind in the determination of volatile carbonaceous is

matter fixed carbon + ash. Fixed carbon is left behind after destructive distillation of

coal. Weight of ash is detected from weight of residue & % age of fixed carbon can

be calculated as

% fixed carbon = 100 [Percentage of moisture + Ash + volatile carbonaceous

mater]

Usefulness of Proximate Analysis

It helps in the assessment of quality of coal in following ways:

1. If moisture contents of coal are low, it is good quality fuel. Moisture contents

are lower the calorific value of fuel. Because, it takes some of the liberated

heat in the form of latent heat of evaporation. 10% moisture contents

produce uniform fuel bed & less fly - ash.

2. High Volatile carbonaceous matter is undesirable as they escape unburnt.

Such a fuel burns with long sooty flame and have low calorific value.

3. Ash in non-combustible material reduces calorific value of coal. Presence of

ash causes early wear out of furnace walls & burning apparatus. Thus, high

ash content lower quality of coal.

4. High percentage of fixed carbon increases calorific value of coal, it also

decreases volatile matter and therefore indicates quality of coal is good.

Proximate Analysis of Peat & Anthracite

S.

No.

Type of coal Moisture

%

Volatile

matter %

Fixed

carbon %

Ash %

1. Peat 20 50 21 03

2. Anthracite 01 08 88 03

N.B.

Calorific value of peat & anthracite are 7700 & 15,000 BTU/pound.

Grading of Coal

Different qualities of coal have following grading on the basis of (i) Ultimate

analysis (ii) Proximate analysis (iii) Calorific value determination;

(1) Peat (2) Lignite and brown coal (3) Sub-bituminous coal (4)

Bitumnous coal (5) Super - bituminous coal (6) Anthracite

Characteristics of Good Quality Fuel

1. It should have high calorific value.

2. Should have low non-combustible matter.

3. Should burn smoothly.

4. Moisture contents should be low.

5. Should not burn spontaneously.

6. Should be of low cost.

7. Should be easily transportable.

8. Should have low ash contents.

9. Should burn at moderate rate.

10. Should burn without smoke.

11. It should not pollute atmosphare.

Gases like CO2, SO2, H2S, PH3 etc. should not form when it burns.

5b.4 "Flash Point"

Use of Kerosene oil containing lower boiling fractions is dangerous in lamps,

stoves etc.; because there are chances of explosion. Therefore, it is needed that

Kerosene or other oil used for heating and illuminating purpose should not be as

much volatile as to form explosive mixture with air at ordinary temperature. The

minimum temperature at which an oil gives sufficient amount of vapours

to form explosive mixture with air is known of flash point. For safety

purpose flash point of oil is fixed by law of the country, depending upon its climate.

For instance, In India, flash point has been fixed 44C. In England and France,

flash points are 22.8C and 55C, respectively.

At slightly higher temperature, the heat from the flash becomes sufficient to

evaporate more liquid and maintains the combustion. The minimum temperature

[Usually 5-40 higher than flesh point] at which oil gives off sufficient vapours

when ignited to continuously burn it for at least five seconds, is known as

fire point of that oil.

Determination of Flash Point

Flash point of an oil can be determined by using Abel's apparatus. The oil to

be tested is placed in a small metallic cup surrounded by water bath & is slowly

heated on water both. Cover (lid) of the metallic cup is opened from time to time &

vapous of oil are ignited by tiny flame introduced momentarily by the means of an

automatic device. The temperature at which the oil vapor burn with slight explosion

is noted which is the flash - point.

The heating of the sample is done at the rate of 5F/minute and speed of

stirring paddle is kept approximately one revolution per second. As the temperature

of the oil reaches within 15F of probable flash point first application of the flame is

made by pulling sliding shutter outwords when the test flame drips into the central

opening in the lid & comes in contact with the ascending vapour-air mixture;

Subsequently, test flame is applied at every 2F rise in temperature. When the

application of the flame first produces a distinct blue flash in the interior of the oil

cup, the temperature on the test thermometer (T1) is recorded and heating is

discontinued. Now, oil is allowed to cool down (if cooling is slow some cold water

may be added to water bath by funnel). When temperature comes within 10F of T1;

test flame is again applied after every 2F fall of temperature & the lowest

temperature at which flash is produced is recorded. This is T2.

. 2

int 021 FTT

sampleoilofpoFlash

Precautions

1. Moisture affects the flash point, hence, all parts of the cup & its accessories

should be properly dried before filling oil in it.

2. No oil should be left between sliding and fixed plates before convering the

cup.

3. Oil should be filled so as it just prevents wetting of the cup above the pointed

tip.

4. For oil with low flash point sample as well as cup may be cooled in melting ice

before filling.

5. For the determination of flash point fresh oil should be used each time. Used

oil gives higher flash point.

6. Thermometer should be kept dipped in oil.

7. While applying flame, slide should be drawn open slowly & closed quickly.

8. Stirring should be stopped while applying flame.

Significance of Flash - Point Determination

1. It is helpful in providing safeguards against hazards during storage, transport

& handling of oil.

2. Liquids having flash point < 140F are known as flammable & those with >

140F are combustible.

3. Volatility of oils increases significantly when heated to or above flash point.

Hence, a low flash point indicates appreciable evaporation loss & possibility of

formation of gas lock in fuel pipe of spark ignition enzines.

4. Flash & fire points are used to detect the solvent contamination and to

determine the approximate extent of dilution of lubricating oils.

5b.5 Aniline Point of Fuels

Aniline is easily soluble in lubricants which are rich in aromatics including

napthelinic compounds. In paraffin rich lubricant dissolution of aniline takes place at

higher temperature. The Tendency of lubricants to mix with aniline is

expressed as its Aniline point. Aniline point is also known as standard aniline

point.

Aniline point with respect to petroleum oils is the lowest

temperature at which oil is completely soluble with equal volume of

freshly distilled aniline. In other words, aniline point is the minimum equilibrium

solution temperature for equal volumes of aniline and sample of lubricant.

Mixed Aniline Point

Some lubricants (with very higher aromatic compounds) when mixed with

equal volumes of aniline, may remain completely soluble and separation into

different phases may not be visible even upon solidification. For the determination of

such low aniline points 1 Volumes of sample is mixed with two volumes of aniline &

one volume of suitable dilutent [n-hexane or n-heptane]. Here, dilutent lowers the

solubility of aniline with lubricant. Hence, with decrease in temperature, separation

of phases may be visible. Equilibrium solution temperature observed under these

condition is known as mixed aniline point which has same significance as

standard aniline point.

Determination of Aniline Point of Fuel

For it equal volumes of sample & aniline are heated till dissolution and are

then cooled under controlled condition. The temperature at which two phases

separate i.e. cloudiness appears throughout the solution is regarded as the aniline

point of the sample.

Methodology

1. Whole apparatus is cleaned & dried at 100-110C.

2. 5-10ml of pure aniline [dried over KOH pellets, filtered & freshly distilled] &

exactly same volume of sample [dried over one Na2SO4] are taken in 2.5 x

15cm test tube of heat resistant glass.

3. Test tube is corked with Cork carrying stirrer and thermometer of suitable

range. The bulb of thermometer is kept 5mm above the bottom of test-tube.

4. This tube is inserted into air-jacket [4x175cm] which is also made up of heat

resistant glass.

5. Contents of tube are stirred to get a homogenous solution. If clear solution is

not formed at R.T. jacket holding tube may be immersed in a hot-bath.

6. Stirring is continued and heating through bath is done till dissolution is

complete. Now hot bath is taken off & temperature is allowed to fall with

stirring at a rate below 1C/minute.[ A cold bath may be used if needed].

7. The temperature at which cloudiness appear is noted. It is aniline point of the

sample. This is 1-2C below the temperature at which turbidity first appeared.

Precautions

1. Apparatus should be completely dry. Even traces of moisture give high

results.

2. Aniline is hygroscopic. Hence, water should not be used even in hot or cold

baths.

3. If aniline point is expected to be below the dew point of atmosphere, space

over sample-aniline mixture should be filled with dry nitrogen.

4. Aniline shoul be measured by pipette with rubber suction bulb or aspirators as

it is highly toxic.

5. Stirring speed should be such that there is no splashing or formation of

bubbles.

Significance of Aniline Point

1. It is a measure of aromatic contents of oil.

2. Low aniline point i.e. high aromatic content make oil attack rubber gaskets,

seals etc.

3. Lubricants with high aniline point are useful for systems where rubber seals

are used.

4. Determination of rubber attacking tendency is easier & takes few hrs as

compared to testing by dipping rubber in oil.

5b.6 "Octane Number"

Octane number is index of Knocking power of gasoline (petrol) in internal

combustion enzines. Modern high speed enzines need high compression for

efficiency. But, a straight run air-gasoline mixture ignites prematurely under high

compression & burns in an explosive & dis-orderly fashion producing a sharp metallic

sound known as Knocking. Knocking leads to loss of power, because part of energy

is converted into rattle. This rattling leads to high fuel consumption & damage to

enzines. Therefore, some anti-knowing agent is added to gasoline. Edger (1927)

observed the normal straight chain alkanes knock badly but branehed ones much

less. Efficiency of a fuel is rated in terms of Octane numbers. n-Heptane is given

octane number zero. But, iso-octane [2, 2, 4-trimethlylpentane] is given octane

number 100.

CH3

|

CH3-CH2-CH2-CH2-CH2 H3C-C-CH2-CH-CH3

| | |

n-Heptane CH2 CH3 CH3

| Iso-octane

CH3

Octane Number of a given fuel is defined as percentage of iso-octane in a

mixture of iso-octane and n-heptane which has same knocking properties as the fuel

under examination in a standard one cylinder enzine operated under standard

conditions. Higher the octane number, higher will be aniknocking property.

It is observed that in a alkane series the octane number decreases as the

carbon chain is lengthened & increases with branching of chains. Octane number

increases as double bond is shifted towards centre of molecule. Octane number of

benzene is 106 and that of alcohol is 95. The aviation gasoline generally has

octane number > 100. It should be noted:

(i) Gasoline from paraffin crudes have low octane number.

(ii) Octane number of normal gasoline in 74.

(iii) The hydrocarbon 2,2,3-trimethyl butane (Triptane) is superior to iso-octane

with octane number 124.

Normally, quality of spirit blend containing TEL (Commonly used fuel] have

different colours which indicate their value. Their octane rating is expressed as:

1003

100 Octane

numberPowerNo

N.B.

Power No. is proportional to power supplied by engine.

Check your progress-IV

Notes:

(a) Write your answer in the space give below.

(b) Compare your answer with those given at the end of the unit.

(i) In ultimate analysis ___________ the estimated.

(ii) Describe determination of aniline point.

(iii) Octane No. of good fuel is low/high.

(i) _________________________________________________

(ii) _________________________________________________

(iii) _________________________________________________

5(b).7 "CALORIFIC VALUES"

Calorific value of a fuel is the amount of heat produced by the

complete combustion of a unit mass of fuel. Actually, this is the number of

parts of water which get heated by the complete combustion of one unit weight of

fuel at 1C provided whole heat is absorbed by the water at atmospheric

temperature and pressure.

Units of caloric values are

1. Calorie

It is unit of heat in C.G.S. system & is defined as amount of heat that

raises the temperature of 1 gm of water by 1C [15-16C].

1 Calorie = 4.185 Joule

= 4.185 x 10-7 erg.

2. Kilo Calories

Kilocalories is the amount or heat require to raise the temperature of 1 Kg of

water by 1C. It is unit of heat is M.K.S. system.

1 K. Cal. = 1000 Cals.

3. Centigrade heat Unit (CHU)

It is the quantity of heat that raises the temperature of one pound of water

by 1C.

1 K. Cal. = 2.2. CHU.

= 3.968 B.t.u.

4. British Thermal Unit (B.T.U.)

B.t.u. is the quantity of heat that raises the temperature of 1 pound of water

by 1F (60-61F).

1 B.T.U. = 252 Cals = 0.252 K. Cals

= 1.054 Joule

= 1.054 x 107 erg.

1 K. Cals. = 3.968 B.t.u.

Net Calorific Value

"Amount of heat evolved when one unit of fuel gets burn completely and

combustion products are allowed to escape is known as net calrofic value".

It is rarely feasible that combustion products of fuel are cooled to R.T., water

vapours escape as such alongwith hot combustion gases and are not condensed.

Net Calorific value = Gross calorific value - Latent heat of water vapours formed

Net calorific value is also known as low calorific value.

Gross Calorific Value

"Amount of heat evolved when one unit of fuel is burnt completely and

product of combustion are cooled to R.T. [15 or 60F] is known as Gross calorific

value".

For the determination of Gross calorific value all hydrogen present in fuel is

converted into steam. When the product of combustion are cooled to R.T. latent

heat of steam also get induced in the measured heat. This total value is known as

Higher or Gross calorific value.

"Determination of Calorific Value"

Object: To determine calorific value of unknown sample.

Principle

The Calorific value is determined by the use of bomb calorimeter. Calorific

values of solid and liquid fuels can be determined by it. Bomb-calorimeter consist of

following parts :

1. Combustion Bomb :

It is made up of chromium - nickel mohybdenum steel and is resistant to

acids as well as corrosion. It weighes approx - 3 Kg. and its capacity in 250-300 ml.

Bomb is provided with an air- tight screw cap to which a couple of stainless steel

electrodes and release valve is attached. To electrode is attached a small ring that

supports crucible containing fuel.

2. Copper Calorimeter

Copper calorimeter is a vessel that is polished outside and it can contain 2-

litre of water when bomb is placed inside. Bombs should be sub-merged in water. A

space should be there between water and cover.

3. Outer Water Jacket

It is made in the from of a wide annular vessel around calorimeter vessel.

4. A Mechanical Stirrer

Mechanical stirrer is fitted for stirring water in calorimeter to stir at uniform

rate.

5. A Beckman thermometer

6. A Crucible

It is made up of nickel, stainless steel or fused silica.

Procedure

Place weighed quantity of fuel in crucible. Keep the crucible containing fuel at

its position supported over the ring. A fine Pt- wire is tightly stretched across the

pole piece of the bomb and one end of the piece of sewing cotton thread is tied

around the wire. Loose end of cotton thread is so arranged to be in contract of with

the fuel (e.g. coal). Now, 10 ml of distilled water is placed inside the bomb by the

means of pipette to absorb vapours of H2SO4 and HNO3 during combustion.

Oxygen is forced into the bomb till a pressure of 25 atm is reached. Now,

bomb is placed inside the copper calorimeter that contains a known amount of water

in which bomb is submerged, but terminal remains above the water level. Make the

electrical connection and place the lid and start stirring through mechanical stirrer.

Note down initial temperature of water by thermometer. Connect the electrodes

with battery & complete the circuit so that sample burns and heat is liberated.

Uniform stirring of water is done and maximum temperature attained is noted by

Beckman thermometer. Now, bomb is left for at least one hr. so that all the acid

mist formed settles down. Dismantle the assembly & bomb is placed on holder.

Release the oxygen from bomb carefully. Open the bomb to examine internal portion

if any unburnt fuel content. If combustion is complete wash the contents with

distilled water quantitatively & transfer the washing in beaker. HNO3 and H2SO4 can

be estimated from these washings (which are formed during combustion) which are

used for corrections.

Calculation of Calorific Value

Rise in temperature of water in which bomb is submerged can be used to

determine gross calorific value :

G.C.V. = m

CCCCtttww CFNSc )())(( 12

Here ;

G.C.V. = Gross calorific Value

w = Weight of water in calorimeter

w = Water equivalent of calorimeter

m = Mass of fuel burnt

t1 = Initial temperature of water in calorimeter .

t2 = Final temperature of water in calorimeter.

CS = Correction for H2SO4

CN = Correction for HNO3

CF = Correction for fuse wire

CC = Correction for cotton thread.

Net calorific value or lower calorific value, L.C.V, can also be calculated by

L.C.V. = G.C.V. (0.09 x 587) cals/gm or K.Cals/Kg.

Hence, 587 cals/g = Latent heat of steam.

H = Percentage of hydrogen in fuel.

Corrections :

1. Acid Correction :

Fuels that contain sulphur and nitrogen get oxidized to H2SO4 , HNO3 ,

respectively at high temperature and pressure.

S + 2H + 2O2 H2SO4 + Heat

2N + 2H + 3O2 2HNO3

These acids can be estimated from the washing of bomb through titration.

For each ml of N/10 - H2SO4, 3.6 cals should be subtracted and for each ml of N/10 -

HNO3 1.43 calories are minused from the actual value of G.C.V. or L.C.V.

2. Cotton thread correction

These corrections are made by the weight of cotton thread used for firing.

Calorific value of cellulose is 4140 cals/gm.

3. Fuse wire correction

This correction is made for the amount of heat given out by the ignition of

fuse wire burnt in the combustion experiment. Heat liberated for each fuse wire

burnt in the experiment is to be subtracted from total heat evolved as per the

instructions of fuse wire manufacturer .

4. Cooling correction

Time for cooling of water from maximum temperature to R.T. should be

recorded . From the rate of cooling and actual time/min (t/min) the cooling

correction of dt x t is added to the rise is temperature. Hence

Caloric Value

=FuelBurntofMass

rrectioncoFuseAcidretionCoolingCorttWw )())(( 12

Result : Calorific value of unknown sample (Fuel) is _______ cals/gm.

Experiment : Determination of calorific value of wax without the use of Bomb

calorimeter [A rough & simplified method]

Methodology :

1. Weigh a wax candle (W1)

2. Take 500 ml Borsil beaker and fill it half with water .

3. Before filling with water as well as after filling with water weight of beaker

should be taken. Difference of there two readings is mass of water (m)

4. Now a thermometer is placed in the beaker and initial temperature (t1) of

water is determined .

5. Now candle is burnt below the beaker as a result beaker of water get heated

& temperature gradually increase. When temperature of water increases by

150 or 200C candle is extinguished to stop heating & exact temperature (t2) is

recorded immediately .

7. Extinguished candle is weighed (w2). The difference is weight of candle (w1-

w2) is the weight of wax burnt.

Observation & Calculation

Initial wt of candle = W1gm

wt after candle burnt = W2gm

1. wt of burnt candle = W1-W2gm

2. Mass of water = mgm

3.(i) Initial temperature of water = t1

(ii) Final temperature of water = t2

Rise in temperature of water = t2-t1

4. Heat absorbed by water = Mass x specific heat x rise in

temperature

= M x S x (t2-t1)

This heat is produced by (w1-w2) gm of wax.

Calorific Value = burntwaxofMan

produceedHeat

= CgmJoulesww

ttsm 0

21

12 //)(

Here, S = Specific heat of water

= 4.2 Joule /gm/00C

Result : Calorific value of wax's is __________ J/g/0C

N.B. : Calorific value determined by this method is rough because :

(i) Heat absorbed by the beaker has been neglected .

(ii) Heat lost to sounding is neglected.

(iii) Loss of heat from beaker & water is neglected.

(iv) Incomplete combustion wax of may have been .

(v) Wrong method of ignition of wax.

5.C "CLINICAL CHEMISTRY"

5c.1 "Composition of Blood"

Utility of blood for normal health and ailing persons is known since time

immortal. Blood is a mixture of different constituents each of which is needed in

definite amount. A test of blood gives indication of certain deficiencies and excess

which lead to ailing condition. Hence, it essential to know composition of blood for a

clinical chemists. Blood constituents can be broadly divide into.

(1) Blood Plasma

(2) Cellular elements.

[1] Blood Plasma

Blood plasma is the liquid part of circulating blood. It contain (a) serum and

(b) Fibrinogen. Later is responsible for the clotting of blood. Upon clotting of blood

fibrinogen is removed along with cells & serum is left behind. Most of the blood

tests are performed on serum.

- Normal range of some clinically important constituents of blood and plasma

(Serum) are summarized below :

(A) Blood

(i) Amino acid nitrogen = 4 - 6 Mg/dL

(ii) Ammonia = 40 - 125 g/dL

(iii) Non-Protein nitrogen = 25-40 mg/dL

(iv) Blood Sugar (Glucose) = 65-90 mg/dL

(v) Urea nitrogen = up to 20 mg/dL

(B) Serum

(i) Albumin = 4-5 g/dL

(ii) Amylase = upto 150 mg/dL

(iii) Bilrubin = Direct upto 0.4 mg/dL

Total upto 1.0 mg/dL

(iv) Calcium = 4.5-5.5 meq/L

(v) CO2 = 25-32 meq/L

(vi) Chloride = 100-108 meq/L

(vii) Total Cholesterol = 140-250 mg/LB

(viii) Cholesterol (ester) = 50-65% of total

(ix) Creatinine = 0.7-1.7 mg/dL

(x) Lipase = upto 1.5 unit

(xi) Lipids (Total) = 350-800 mg/L

(xii) Fatty acids = 200-400 mg

(xiii) Globulins (Total) = 2.5 - 3.5g/dL

-1 …………….. = 0.1 - 0.4 g/dL

-2 …………….. = 0.3 - 0.7 g/dL

…………….. = 0.4 - 0.9 g/dL

………………. = 0.6 - 1.3 g/dL.

(xiv) Iron = 50-190 g/dL

(xv) Mg = 1.5-2.5 meq/L

(xvi) Phosphatase (Acid) = upto 4 (Gutman units)

(xvii) Phospholipids = 100-250 mg/dL

(xix) Phosphorus (inorganic) = 3 - 4.5 mg / dL

(xx) K (Potassium) = 3.8 - 5.6 meq/L

(xxi) Protein (total) = 6.5 - 8.0 g/dL

(xxii) Protein bound iodine = 3.5-8.0 g/dL

(xxiii) Sodium = 138 - 146 meg/L

(xxiv) Transaminase (SGO) = upto 40 units.

(xxv) Uric Acid = 3 - 6 mg/dL

B = Varies with age.

A brief study of components of blood plasma is discussed ahead:

(A) Water = 91 - 92%

(B) Other Solids = 8% - 9%

(i) Organic Substances

(ii) Inorganic substances

(iii) Respiratory gases.

(I) Organic Substances

These are 7.1 - 8.1%

They include

(i) Proteins (=7.0%) : Regulate blood volume, viscosity & osmotic pressure.

e.g.

(a) Albumin

(b) Globulin

(c) Fibrinogen

(d) Prothrombin

Fibrinogen is responsible for the clothing of blood.

(ii) Hormones : are secreted by endocrime glands.

(iii) Enzymes : Amylase, Lipase, sucrase etc.

(iv) Antibodies : Maintain viscosity & immune system.

(v) Neutral Fats : e.g. Cholesterol, pentoses, Phospholipids etc.

(vi) Non-Protein Nitrogenous Substances e.g: urea, ammonia, amino acids

and creatinine etc

(II) Inorganic Substances

NaCl, Ca, K, iodine, iron, bicarbonates etc.

(III) Respiratory Gases

O2 and CO2.

[2] Cellular Elements

Following types of cells are suspended in liquid portion of blood:

(a) Red Blood Corpsules (R.B.C.)

(b) White Blood Corpsules (W.B.C.)

(c) Platelets (Thrombocytes)

(a) R.B.C.

These are also known as erythrocytes and are produced in bone marrow of

flat bones, ribs, vertebrae, heads of humerus and femur. Their size is 7.2 micron

diameter. They contain no nucleus. R.B.C. contain red pigment haemoglobin & their

life is 120 days. R.B.C. are responsible for the transportation of O2 & CO2 from one

tissue to other.

(b) W.B.C.

These are also known as Leucocytes and are of five types :

(i) Neutrophil polymorph

(ii) Eosinophil

(iii) Basophil

(iv) Lymphocytes

(v) Monocytes.

(i) to (iii) are also called granulocytes. (iv) and (v) are non-granular

leucocytes.

There is only one W.B.C. for every 500 R.B.C. In adults they count 5,000-

10,000 per cm. of blood. They do not contain pigment.

They constitute defence systems of body against infections by phagocytes.

Their function is also production of antibodies by lymphocytes.

(c) Platelets

These are non-nucleated parts of cytoplasm & are also called thrombocytes.

[Thrombo = Clottings, cyte=cell], they cause clotting of blood & are produced in

spleen and bone-marrows. Size of platelets is 2-4 micron (diameter) and they count

2,50,000 to 5,00,000/cc of blood.

Functions of Blood

(1) It transports food from one tissue to other & provides connection link

between individual cells of distant organs and tissues.

(2) It carries oxygen from lung to other parts by combining with haemoglobin &

removes CO2 from tissues through lungs to air.

(3) Blood regulates body temperature & maintains water contents of body.

5c.2 Collection and Preservation of Samples of Blood

For the analysis of blood samples for glucose, cholesterol, uric acids, lipid

profiles, R.B.C., W.B.C., platelets etc collection and preservation of blood samples is

needed. Blood for some distinct purpose is collected after fasting over night.

Collection of Blood

The blood is collected aseptically from the median cubital vein, in front of the

elbow, into a sterile container containing an anti-coagulant solution. During

collection the bottle is shaken gently to ensure that the blood and anti-coagulant are

mixed well, therefore, preventing the formation of fibrin-clots. Not more than 420 ml

of blood is taken at single attendance. Now container is sealed immediately and is

cooled to 4-60C. For taking blood the equipment used is made up of plastic & is

disposable. Container is also made up of plastic. In America plastic bags are used.

Anti-Coagulants

(1) Citrates

The solution most often used as anticoagulant of blood is Acid-citrate

dextrose (ACP) which has following composition :

Sodium acid citrate = 2.10 - 2.5 g

Dextose = 3.0 g

Water for injection = upto 120 ml.

The citrate prevents clotting of blood by binding to Ca2+ ions as unionised

calcium citrate. Earlier, trisodium citrate was used as anti-coagulant which has very

alkaline pH & caused conisiderable darkening of dextrose during sterilization and the

two solutions need to be autoclaved separately. Acid citrate gives a pH of 5 & gives

very little or no caramelisation. Also, it is less likely to induce flaking of the glass of

container. High concentration [2.5 g/20ml] is generally used as it more efficiently

reduces the clot - formation.

Dextrose delays haemolysis of electrolyte in vitro & prolongs their life after

transfusion.

2. Heparin

Heparin is naturally occurring blood anti-coagulant made by the mast cells of

connective tissue surrounding the blood-vessels. It inhibits clotting of blood in

circulatory system. Heparin is used in the blood transfusion when more amount of

blood is to be given to the patient and corresponding amount of citrate would be

harmful e.g. in cardic surgery. It quickly loses activity in blood in vitro & normal

quantities are effective for about a day. Heparin is expensive may continue its action

after transfusion, needing the administration of neutralizing agents like protamine

sulphate.

3. Disodium Edetate

It is preferred when preservation of platelets are necessary. This is a

chelating agent because of strong affinity for divalent metal like Ca.

Collection of Blood of an HIV Infected Patient

The collection & handling of blood requires great care as some transferable

disease constituents like HIV or AIDS may be present in it. To collect blood of such

patient gloves and masks should be used. Such persons should not be handled

without expert advise.

Collection of Blood for Plasma or Whole Blood Analysis

Blood for this purpose is collected in tubes containing anti-coagulant. Anti-

coagulants used have already been discussed. However, potassium oxalate (about

1mg/ml blood) may also be used as anti-plasma coagulant. Pot. oxalate precipitates

blood calcium which is required in clotting. Potassium oxalate causes R.B.C. to shrink

& intracellular water diffuses into plasma.

Collection of blood for serum Analysis

Blood for this purpose is also collected in dry & clean tube to prevent

haemolysis & contamination. Haemolysis is destruction of R.B.C. & release of

haemoglobin etc into serum or plasma. As haemolysis occurs, serum becomes red

instead of normal straw colour. Therefore, blood sample is centrifuged as soon as

possible to separate serum or plasma from cells.

Collection of Blood for Glucose Analysis :

NaF is widely used as a preservative for the samples to be analysed for

glucose alongwith anti-coagulant. NaF is enzyme inhibitor & prevents enzymatic

break-down of glucose. 1 mg of NaF/ml of blood is enough.

Collection of Blood for CO2 Analysis

Blood collected for this purpose should be kept anaerobically & mineral oil

must be added to collection tube which being ligther covers the blood. A rubber

stopper should not be used to such sample which swells up.

Storage of Samples of Blood

Apart from period of transport and examination which much not exceed 30

minutes, blood should be stored at 4-6C until required for use. Even, at his

temperature some deterioration may occur. Leucocytes disintegrate in few hrs and

platelets in few days. R.B.C. show fall in ATP and other organic phosphates, a

reduction in oxygen carrying capacity and partrial loss of lipid from their membranes

& increased fragility. Storage at R.T. even for a day seriously reduces post-

transfusion survival of R.B.C.. Haemolysis makes blood unfit for use. Complete

haemolysis, especially if it occurs rapidly is a sign of bacterial infection but its

absence is not confirmation of sterility since some bacteria predominatly

pseudomonas & bacteria of coli-aerogenes group, can grow in blood at refrigerator

temperature without causing haemolysis. Few organisms isolated from contaminated

blood use citrate as their source of carbon which eventually leads to clotting.

5c.3 "Analysis of Serum Electrolytes"

Electrolytes are the substances which dissociate into free ions when dissolved

or are in molten state. They constitute electricity conducting medium. Electrolytes

generally exist as acids, bases salts. Electrolytes present in blood are : Sodium,

Potassium, Calcium, Chloride, bicarbonates etc.

"Estimation of Sodium & Potassium"

In blood sodium and potassium are found in ionic state. Plasma contains 90%

of the total blood sodium. But, potassium in present mainly in cells. Concentrations

of Na+ & K+ present in serum can be determined by the flame photometry or by

chemical analysis based on precipitation of metal complex. Potassium in serum can

be estimated by precipitation of potassium as followed by photometric or titrimetric

method.

Methodology

Flame photometric method involves following steps:

1. Sample in solution form is introduced in the form of fine continuous spray into

non-luminous gas using either acetylene, propane or butane gas. The light is

emitted by the use of colour filter or diffraction grating.

2. The emitted light of a wave length characteristic of ion being analysed is

isolated and focused on a photoelectric cell.

3. The electrical response to photoelectric cell is measured on suitable meter

which is already calibrated to convent electrical impulse to ion concentration

either by the direct reading or by reference to calibration curve.

Range

(i) Normal range of serum Na+ ions is 300-350mg/100 ml or 130-154 mEq./lt

(ii) Concentration range of K+ions in serum is 14-22 mg/100ml or 3.6-5.6

mEq./lt.

Inferences from Na+ and K+ion concentrations

- Increase in serum potassium causes Addison disease, acute bronchial asthma

& fevers.

- Decrease in concentration of serum potassium is due to diarrhoea or vomiting

during familial periodic paralysis.

- Sodium ions maintain acid-base balance in the body as well as the smotic

pressure.

"Estimation of Calcium Ions"

Calcium is present in serum as :

(i) Calcium bound to protein.

(ii) Calcium bound to other organic substances like citrate.

(iii) Ionized calcium.

Physiological functions of calcium are due to ionic calcium. But in routine work

total calcium is estimated. Commonly used method for the estimation of

calcium is Clark & Collip Method.

Principle

Calcium present in serum can be precipitated with ammonium oxalate in the

form of calcium oxalate. This precipitate is washed with ammonia in order to remove

excess of oxalate and then calcium oxalate precipitate is treated with H2SO4 to

convert oxalate into oxalic acid. Oxalic acid is titrated with standard KMnO4 solution

is usual manner.

Requirements

(i) Ammonium Oxalate 4%

Prepared by the dissolution of 4g ammonium oxalate in water & made up to

100 ml in volumetric measuring flask with D.W.

(ii) 2% Ammonia

2 ml of H2SO4 diluted to 100 ml with distilled water.

(iii) 1N-H2SO4

28 ml of H2SO4 diluted to 1000 ml with distilled water

(iv) Stock KMnO4 0.1 N Solution

23.159 gm of KMnO4 is dissolved in water & made up to 100 ml. This solution

is allowed to stand for a week & then is filtered through asbestos

(v) 0.01 N - Sodium Oxalate

0.67 gm of sodium Oxalate is dissolved in water & 5 ml of conc. H2SO4 is

added to it. The volume is made upto 1000 ml with water.

Methodology

1. Place 2 ml of serum, 2 ml of water and 1 ml of 4% ammonium oxalate

solution in centrifuge tube. Mix them thoroughly and allow to stand for about

half an hour.

2. Mix again and centrifuge at 1500 g for about 15 minutes.

3. Take our supernatant liquid. Drain the centrifuge tube by inverting it on a

filter paper for few minutes.

4. Add 3 ml of ammonia [2%] and shake, centrifuge again drain as in step 3.

5. Add 2 ml of 1N-H2SO4 and shake.

6. Keep the tube in boiling water-bath with occasional shaking till precipitate

completely dissolves.

7. Titrate the warm solution with 0.01N-KMnO4 till pink colour develops and

persists at least for one minutes.

8. Find out the volume [ml] of 0.01N-KMnO4 used. Let it is Xml

9. Take a blank reading with 2 ml of 1N-H2SO4 by titrating it against 0.01 N-

MKnO4. Let volume used is Y ml.

Calculation

Serum calcium [mg/dL]

1002

2.0)( YX

= (X-Y) 10

Range

Range of calcium is serum varies from 9-11 mg/DL in a healthy person.

Inference from the Concentration of Serum Calcium

- Serum calcium increases in hypervitaminosis-D, hyperparathyroidism,

polycytharmia, infantile hypercalcemia, sarcoidosis, multiple myeloma,

extensive metastatic involvement of bones etc.

- Serum calcium decreases in hypoparathyroidism, rickets, renal failure, acute

pancreatitis, starvation, naphrotic syndrome, osteomalacia.

"Estimation of Chloride in blood"

Chloride is an important electrolytic ion present in body. It is responsible for

osmotic pressure control, chloride - bicarbonate shift, acid-base balance etc. One-

third of total chloride is present in R.B.C. and 2/3 is serum. It can be estimated by

Schales and Schales method.

Principle

Chloride ion gets converted into un-ionized mercuric chloride when mercuric

nitrate solution is added to them.

2Cl- + Hg (NO3)2 HgCl2 + 2NO3-

Endpoint is indicated by the appearance of bright blue - violet colour in

presence of diphenyl carbazone indicator. Titration can be done directly with serum.

But highly coloured or jaundiced sample, may suffer from clarity of end point. For

such sample, a Folin Wu tungstate filtrate is prepared and titrated.

Requirement

(i) 10% Sodium tungstate.

(ii) 2/3 N-H2SO4

(iii) Hg (NO3)2 Solution : To prepare it dissolve 3g of Hg (NO3)2 in

500 ml of D.W. Add 30 ml of conc. HNO3 to it, shake and make up the

volume to 1 litre.

(iv) 1% solution of diphenyl carbazone in CH3OH or C2H5OH. [Indictor].

(v) Standard NaCl Solution : To prepare it dissolve 585 mg of NaCl in 1

lt D.W. Concentration of this solution is 10 m Eq./litre.

Methodology

1. Standardization of Hg (NO3)2 Solution

Taking 2 ml of standard NaCl solution in 50 ml conical flask, add 3-4 drops of

diphenyl carbazone to it. Now titrate it with Hg (NO3)2 till colour change occurs. Note

down the volume used.

2. Titration of Sample

Taking 1 ml of serum or plasma or blood and add 7 ml of D.W. to it. Add 1 ml

of 10% sodium tungstate & 1 ml of 2/3 N-H2SO4 also. Stir the contents and filter.

Taking 2 ml of this filtrate in 50 ml conical flaks titrate it with Hg (NO3)2

solution. Note down the volume used.

Calculation

Volume of serum has been diluted 10 times. If the concentration of Cl ion in

serum is C, then

10standard with used)Hg(NO of vol.

sample with used)Hg(NO of Vol.

10

C

23

23

100 standard with used )Hg(NO of Vol

sample with used )Hg(NO of Vol.Eq/l m C

23

23 or

Range

Rage of Cl- ion

(i) in Serum plasma = 98-105 m Eq/lt

(ii) in whole blood = 78-85 mEq/lt

Inference from the Concentration of Cl- Ions in Plasma

- Increase in concentration of Cl- ions in plasma takes place in nephritis. Under

such conditions salt in take should be restricted.

- Decrease in Cl- ion concentration in plasma is indication of gastrointestional

disturbances associated with diarrhoea & vomiting.

- Decrease in concentration of Cl- ions also occurs during Addison disease &

pneumonia.

"Estimation of HCO3- ions"

Bicarbonate (HCO3-) ions in blood can be determined by adding an excess of

0.01 M-HCl to volatilize the HCO3- ions to CO2 & swirling to allow the CO2 to escape.

The excess of HCl is back-titrated with 0.01M-NaOH. The 0.01 M-HCl and NaOH

solutions are prepared by diluting standard 0.1 M solutions.

HCO3- + H+ H2O + CO2

H+ + -OH H2O.

Requirements

(i) 1% saline (NaCl) solution in CO2-free water.

(ii) Phenol red solution 0.1% in 0.003 M-NaOH

(iii) Anti foam A

(iv) Standard 0.1 M-HCl & 0.1 M-NaOH.

0.01M-HCl and 0.01M-NaOH should be freshly prepared in saline solution.

Saline helps in the volatilization of CO2 from acidified solution.

Methodology

1. To prepare sample take 10-15ml of fresh blood in a sample tube.

2. Add NaF to it in order to prevent glycolysis [decomposition of glucose], which

may lead to pH change.

3. Keep the tube anaerobically, for which stopper the sample tube to keep CO2

out. Sample should be prepared at the time of analysis only.

4. Take 6 ml of 1% saline in 25 ml Erlenmeyer flask and add 0.1 ml of serum or

plasma.

5. Now add 2-3 drops of phenol red indicator to it, stopper the flask and mix

gently. End-point of this titration is in the pH range of 8.4-6.7 by the colour

change from yellow to red.

6. The pooled plasma or serum sample is prepared by touching end of stirring

rod to the Antifoam A & rotating it. This prevents excessive foaming.

7. Place 0.1 ml of plasma or serum in 25 ml capacity Erlenmeyer flask & add 1

ml of 0.01 M-HCl, 4 ml of 1% saline to it. Shake the flask for 1 minute so that

CO2 gas goes out.

8. Now add 2-3 drops of indicator and titrate with 0.01M-NaOH till pink colour

appears.

Calculation

0.1ml of blood sample was taken & 0.26 ml of 0.01 M-HCl might have been

consumed if the normal value of calcium [26 m Eq/l] was present in blood. As 1 ml

of 0.01 M-HCl was taken, 0.74 ml of it should have been left un-reacted & back

titration might has consumed about 0.7 ml of 0.01M-NaOH. From latter reading (X

ml) amount of HCO3- ion in blood can be calculated and expressed in meq/lt.

Conc of HCO3- in meq/lt = 1 ml of 0.01 M-HCL - X ml of 0.01M-HCl

Check your progress-V

Notes:

(a) Write your answer in the space give below.

(b) Compare your answer with those given at the end of the unit.

(i) O2 reacts with blood to give ________________ .

(ii) Why heparin (Sod. slat) & potassium oxalate are added to blood.

(iii) Write application of Radioimmunoassay.

(i) _________________________________________________

(ii) _________________________________________________

(iii) _________________________________________________

5c.4 Estimation of Serum Proteins

[Albumin and Globulin]

Principle

Albumin protein present in serum binds with bromocresal green at pH of 4.1

to give green coloured complex. Intensity of colur is proportional to the

concentration of albumin, therefore, it can be determined colorimetrically at 640 nm

(or using red filter).

Chemicals Required

(i) Albumin reagent

It is prepared by mixing following chemicals in 900 ml of distilled water:

(a) Succinic acid = 8.85 g

(b) Bromo Cresol Green = 108 mg.

(c) Sodium azide = 100 mg

(d) Brij 35 = 4.0 ml

pH of the solution is adjusted to 4.1 using NaOH and the volume is made up to 1

litre.

(ii) Albumin Standard : Contains 4.0 gms/dl in normal saline alongwith 0.1

gm/dl sodium azide.

Methodology of Estimation : 5 clean and dry test tubes are taken and numbered

as 1, 2, 3, 4 and 5. Reagent and their quant ities added to each test tube are

given in the following table:

Reagent (ml) Test tube

(1) (2)

Standard

(3) (4)

Blank

(5)

(i) Albumin reagent

(ii) Serum (1:10 dilution)

(iii) Albumin Standard (1:10

dilution)

(iv) Distilled water

5.0 5.0

0.5 0.5

- -

- -

5.0

5.0

0.5 0.5

- -

5.0

-

–

0.5

Absorbance of all the test tube solution is recorded at 640 mm.

Calculations :

Serum albumin (g/tube) [0.05 ml of serum]

002.0ODs

ODt[Conc. of standard tube]

Serum albumin (gm/dl)

05.0

100002.0

ODs

ODt

4ODs

ODt

Normal value of serum albumin = 3.3-4.8 gm/dl

Serum Globulin (g/dl) = Total protein-Albumin

A/G ratio = /dl)globulin(g Serum

dl)albumin(g/ Serum

Clinical Diagnosis

Higher value of serum albumin is noted during dehydration due to

hemoconcentration. Decrease in serum albumin is noted during severe malnutrition,

renal diseases, pregnancy, liver inefficiency and burn.

However, serum globulin is increased during chronic infections, autoimmune

diseases, multiple myeloma & macroglobulinemia.

Estimation of serum protein by Biuret method of Reinhold.

Principle

Biuret method (most commonly used method) of determination of serum

protein is based on the principle that subrtances which contain two-CONH2 groups

or more groups joined together or those containing peptide linkages give purple

colour with alkaline CuSO4. One Cu-atom complexes with four molecules of biuret &

central nitrogen is involved in linkage. The amount of colour varies with different

proteins and carbohyhate contents in complex protein.

Chemicals required

(i) Biuret Reagent Stock :

This stock is prepared by dissolving 45 gms of sod. potassium tartarate in

approx. 400 ml of 0.2 N-NaOH and adding 15 gms of CuSO4 to it with continuous

stirring. 5.0 gms of KI is also added to it and volume is made upto 1 litre with 0.2 N-

NaOH.

(ii) Standard protein solution :

Bovine serum albumin 0.5 g/100 ml.

(iii) Biuret Reagent

200 ml of stock reagent is diluted to 1 litre with 0.2 N-NaOH containing 5.0

gm of KI/litre.

Methodology of estimation

In 6 dry & clean test tubes different solutions are added in the quantities

given in following Table:

Reagent (ml) Test

(1) (2)

Standard

(3 (4) (5)

Blank

(6)

(i) Serum (1 : 10 dilution)

(ii) Standard Protein solution

(iii) Distilled water

(iv) Biuret reagent

1.0 1.0

– –

2.0 2.0

3.0 3.0

_ _ _

1.0 1.5 2.0

2.0 1.5 1.0

3.0 3.0 3.0

–

–

3.0

3.0

Mix the solution in each test tube; keep on water-bath at 370C for 10 minutes

& record the absorbance at 540mm calorimetrically using green filter.

Calculations

Draw calibration curve & find out total protein present in serum by reading

absorbance of sample from the curve.

Normal value of serum protein is between normal 6-8%. An increase in

normal value is noted due to dehydration and decrease is due to excess of water

intake.

Hyporproteinemia:

Is due to increased globulin synthesis, chronic liver fever, chronic infections

like Kalazar, bone disease like multiple myeloma, collagen discease etc.

5c. 5 "Estimation of Glucose"

Estimation of glucose in the given sample colorimetrically.

Chemicals Required

(i) Standard sugar solution

To prepare it dissolve 25 mg of glucose in water and make up the volume to

100 ml. This solution contains 250 g glucose/ml. For obtaining calibration curve 0.1

to 1.0 ml of this solution are used.

(ii) Anthrone reagent :

(0.2 % anthrone in 70% H2SO4). It is always prepared fresh & is allowed to

stand for 30-40 minutes before use.

Principle :

Anthrone reagent upon heating with glucose gives green or blush green color.

Hence, colorimetric method can be used.

Methodology of estimation

Pipette out 10 ml of freshly prepared anthrone reagent in a test tube. Chill it

in ice cold water. Take 1 ml of sugar extract and dilute to 10 ml with water. Take

out 1 ml from this diluted sugar extract and layer on anthrone reagent. Cool it for 3-

5 minutes and mix the contents thoroughly while still immersed in ice-cold water.

Heat the contents in boiling water-bath for 10 minutes. Then immediately cool in

cold water. Record absorbance at 526 nm against blank. From calibration curve

sample absorbance may be determined.

Estimation of blood sugar (glucose) calorimetrically

Principle

Astor and king method (1954) of estimation of glucose is based upon the fact when

blood is kept into isotonic sodium sulphate-copper sulphate solution no further

copper sulphate is required. Upon addition of sodium tungstate to it copper

tungstate if formed & proteins as well as non-glucose reducing substances are

preipitated. Results obtained by this method are very close to glucose concentration.

From the filtrate concentration of glucose is determined by the use of its property to

reduce alkaline cupric (Cu2+) ions producing Cu2O (cuprous oxide). Cu2O reduces

phosphomolybdic acid to molybdenum blue which can be measured photometrically.

Reagents required

(i) Isotonic Na2SO4 – CuSO4 Solution

To prepare it dissolve 30gms of Na2SO4. 10 H2O and 6 gms of CuSO4. 5H2O in

distilled water & make up the volume to 1 litre.

(ii) Sodium tungstate solution :

It is prepared by dissolving 10 gms of sod tungstate (Na2WO4. 2H2O) in water

& making up the volume to 1 litre.

(iii) Alkaline Tartarate Solution

For it 25 gms of NaHCO3 is dissolved in approx. 600 ml of water in 1 litre

beaker. 20 gms of Na2CO3 is added to it with shaking to dissolve 18 gms of

potassium oxalate is dissolved separately in warm water and carbonate mixture is

added to it. 12 gms of sod-potassium tartarate is also dissolved separately in small

quantity of water & it is mixed to previously prepared solution & volume is made

upto 1 litre.

(iv) Phosphomolybdic acid reagent

35 gms of molybdic acid, 5 gms of sodium tungstate and 20 gms of NaOH are

boiled with 300 ml of DW in 1000 ml beaker for 20-40 minutes to expel ammonia

present in molybdic acid. Cool the solution & transfer in 500 ml volumetric flask.

Now add 125 ml of conc. Orthophosphoric acid (85% H3PO4) and make up the

volume to 500 ml with DW.

(v) Standard Glucose Solution (Stock Solution)

For it dissolve 100 mg of pure glucose in 100 ml of isotonic Na2SO4-CuSO4

solution.

(vi) Working Glucose Standard (2 mg%)

To make it pipette accurately 2.0 ml of stock glucose solution in 100 ml

volumatrie flask & make upto mark with isotoric Na2SO4-CuSO4 solution.

1 ml = 0.02 mg glucose.

Methodology for Estimation

Pipette out 3.8 ml of isotonic solution in centrifuge tube. Add 0.1 ml of blood

serum or plasma & mix it. Add 0.1 ml of 10% Sod. tungstate, mix and centrifuge

after 5 minutes. Transfer the supernatant into clean tube & precipitate is discarded.

Following amounts of different reagents are added to 1-5 clean & dry test tubes.

Reagent (ml) Test

(1) (2)

Standard

(3) (4)

Blank

(5)

(i) Supernatant

(ii) Standard glucose

(iii) DW

(iv) Isotonic

(v) Alkaline tartarate

1.0 1.0

– –

– –

1.0 1.0

1.0 2.0

_ _

1.0 1.0

– –

1.0 1.0

2.0 2.0

–

–

1.0

1.0

2.0

Mix the solution & heat on water - bath for 10 minutes. Cool, add to test tube

3.0 ml g phosphomolybdic acid. Mix & record absorbance after 5 minuts at 680 nm.

Calculations

mg of glucose in test/0.25 ml of blood/plasma/serum

).ubestandard/t of conc(02.0ODs

ODt

Blood/serum/plasma glucose (mg/ml)

80ODs

ODt100

025.0

02.0

ODs

ODt

Normal values (fasting)

Venious or capillary whole blood = 60-100 mg/dl

Renal threshold for glucose = 180 mg/dl

Plasma or serum = 70-110 mg/dl

Clinical diagnosis

Blood sugar increases during Diabetes mellitus, hperthyroidism,

hyperadrenalism, hyperpituitarism. however, it decreases during Addison's disease,

hyperinsulinism & glycogen storage disease. In old age level is higher.

5c6: Estimation of blood urea nitrogen

Blood urea nitrogen means amount of nitrogen in blood coming from urea.

Urea is secreted is body by liver and removed from blood through kidney. It can be

estimated flame photometricaly as well as colorimetrically.

Increase in blood urea nitrogen occurs in body during dehydration or shock

and also during gastrointestinal haemorrhage.

Decrease in blood urea nitrogen is of little importance but it leads to liver

problems & poor nutrition. Over dehydration probably from intravenous fluids also

leads to low blood urea nitrogen.

5c.7 Estimation of Uric acid in Serum

Uric acid is the product of urine metabolism in primates, birds and reptiles.

Nucleic acids degrades in presence of nucleases to give free purine & pyrimidin

bases. Estimation of uric acid is based upon its reaction with phosphotungstic acid.

Important method for the estimation of uric acid is due to Heny et al. (1957).

Principle

Uric acid gets oxidised with phophotungstic acid in alkaline medium. In the

process phosphotungstic acid gets reduced into a blue complex which can be

determined calorimetrically between 650-700nm.

Requirements

1. 10% sodium tungstate.

2. 2/3 N-H2SO4 : To prepare it add 18.8 ml of conc. H2SO4 to 500 ml of D.W.

and dilute to 1 lt.

3. 70% Na2CO3 solution .

4. Phosphotugstic acid regent : It can be prepared by dissolving 40gm Sod.

tungstate in 300 ml water. Add to it 30 ml of orthophosphoric acid and glass

beads. Refluxing is done for 2hrs. cool it to R.T. & dilute to 1lt. Dissolve 32

gms lithium sulphate in the reagent and mix thoroughly. Store the reagent in

refrigerator.

5. Stock solution of uric acid : To prepare it add 100 mg of accurately

weighed uric acid and 60 mg of lithium carbonate into 100ml volumetric flask.

Mix 100 ml of D.W. in it and warm to 600C. Cool to R.T. and make the volume

upto the mark. This solution contain 1mg/ml.

6. Standard Uric Acid solution: (0.02mg/ml). It can be prepared by diluting

2.0 ml of stock solution to 100 ml with D.W.

Methodology

1. Dilute 1ml of plasma with 8 ml of D.W., 0.5 ml of 10% sodium tungstate and

0.5 ml of 2/3 N-H2SO4. Mix the contents well and centrifuge . Uric acid is

tested from the supernatant.

2. To test uric acid take 5 test tubes and lebel 1-5; 1 & 2 contain sample;

standard (0.04mg/tube) are in 3 & 4 and t.t. 5 is for blank reading.

Compositions in test tubes 1-5 are as given in following table :

Reagents (ml) Sample Standard Blank

t.t.1 t.t.2 t.t.3 t.t.4 t.t.5

1. Supernatant 2 2 - - -

2. Uric Acid (Standard ) - - 2 2 -

3. D.W. - - - - 2

4. Na2CO3 Solution 2 2 2 2 2

5.Phosphotungstic Reagent 3 3 3 3 3

3. Mix the contents of each tube thoroughly allow and the tubes to stand at R.T.

for 15 minutes.

4. Read the O.D. against blanks [t.t.5] at 700-710 nm (Red filter)

Calculation

mg of Uric acid/tube i.e. 0.2 ml of blood

= ).t.t/sandardof.Conc(04.0×SOD

TOD

Serum Uric acid (mg/dl)

= 100×2.0

04.0×

SOD

TOD

= ×SODTOD

20

Range

Range of uric acid in serum of a healthy pession in 2-6 mg./dL.

Inference from the concentration of Uric acid

- Increase in uric acid [6.5-12mg./100ml of Serum] in an indication of gout.

Gout is a disease of joints identified by the depositions of urates as cryratals.

- Malfunctioning of kidney may also lead to increase in uric acid contents in

blood ranging from 4-20mg/100ml. However, extra renal functions also have

effect on serum level.

- Elevation in uric acid in serum level may also be seen in the case like

leukemia, lobar pneumonia, large abcesses, toxemia of pregnancy etc.

- Increase in uric acid in urine is also accompanied by uric acid increase in

blood.

- Decrease in concentration of uric acid has been recorded during Wilson's

disease and fanconi syndrome.

5C.8 Determinations of Barbiturates

Exercise 1

Determination of Phenobarbital (Luminal)

Methodology

Dissolve in a conical flask accurately weighted 0.1g of sample in 5ml of

pyridine and add 0.25 ml of thymolphtalein solution as well as 10 ml of AgNO3 –

Pyridine reagent to it. Titrate the contents with 0.1 N-NaOH (alcoholic) till blue color

appears.

Calculation

1.0 ml of 0.1 N-NaOH - 0.011610g of Phenobarbital.

Exercise -2

Determination of Cyclobarbitone calcium.

Methodology

as in Ex-1

Calculation

1 ml of 0.1 N- NaOH - 0.02553 g. of cyclobarbitone Calcium.

Exercise -3

Determination of Quinobarbitone sodium.

Methodology

Same as Ex -1

Calculations

1ml of 0.1 N- NaOH = 0.02603g of Quinobarbitone sodium.

5C.9 Estimation of Serum Alkaline Phosphatase

Phosphates are the enzymes that catalyse the removal of phosphates form

certain monophosphoric esters. This enzyme is most active at the pH-10.

Phosphatases are intercellular but are also present in smaller amounts in plasme

certain diseases their amount increases in plasma. Most popular method to

determine concentration of alkaline phosphatases in plasma in King and King

(1954) method.

At a pH of 10, phenyl phosphate is hydrolysed to phenol when incubated with

alkaline phosphatases. The phenol formed condenses with 2-amino antipyrine. The

product formed, after the oxidation with alkaline potassium ferrocyanide gives red

colored complex which can be estimated at 520 nm.

Requirements

1. 0.1N-Disodium phenylphoshpate : To prepare it 2.18g of disodium

phenyl phosphate is dissolve in a lt. of D.W Boil the solution, cool it and

preserve with 1ml of chloroform at 40C. This solution rest for 3-4 weeks.

2. 0.5N-NaOH : To prepare it dissolve 20 g of NaOH in 1lt. of D.W.

3. O.1N-Carbonate buffer : It is prepared by the dissolution of 6.36 g of

anhydrous Na2CO3 and 3.36g of NaHCO3 in distilled water. This solution is

made up to 1lt. with D.W.

The pH of this buffer is 9.5-10.0

4. 0.5N-NaHCO3: For this solution 4.2 g of NaHCO3 is dissolved in 100 ml of

D.W.

5. 0.6% 4-Amino antipyrine: To prepare it dissolve 600 mg of 4-amino

antipyrine in 100 ml of DW.

6. K4[Fe(CN)6] : 4% Potassium ferrocyanide is prepared by dissolving 4g of it

in D.W. & diluting it to 100 ml with D.W. This solution should be prepared

fresh and must be stored in brown bottle.

7. Standard stock solution of phenol: 1mg/ml solution is prepared by

dissolving 100 mg of pure phenol in 100 ml of 0.1 N-NaOH.

Methodology

1. Four test tubes are lebelled as 1,2,3 & 4. They contain sample, control,

standard and blank. They are filled with following solution:

S.No. Reagents 1 2 3 4

1. Disodium Phenyl phosphate 1.0 1.0 - -

2. 0.01N-Carbonate buffer 1.0 1.0 1.1 1.1

Incubate in water bath for 15 minutes at 370C

3. Serum 0.1 - - -

4. Standard phenol soln. - - 1.0 -

5. D.W. - - - 1.0

Again incubate in water bath for 15 minutes at 370C

6. 0.5N-NaOH 0.8 0.8 0.8 0.8

7. Serum - 0.1 - -

8. 0.5 N-NaHCO3 1.2 1.2 1.2 1.2

9. 4-Amino antipyrine 1.0 1.0 1.0 1.0

10. K4[Fe(CN6)] 1.0 1.0 1.0 1.0

Thus total volume in each tube is 6.1 ml.

2. O.D. of solution in each test tube is measured at 520nm against blank .

Calculation

Serum alkaline phosphatases

(In king Armstrong unit)

= 10.

...

S

CT

DO

DODO

King Armstrong unit: 1 mg of phenol liberated by 1dl of serum under assay

conditions.

1K.A. Unit = 7.1 U/L

Range: Range of serum phosphatases in a normal adult is 3-14 KA- Unit or 22-92

U/L. Level of alkaline phosphates is about 2.5 times in actively growing children.

Inference from the level of alkaline serum phosphates

1. Increase in level have been found during rickets, osteomalacia and

osteoblastic tumors etc.

2. Serum alkaline phosphatases activity also increases during disease of liver &

bialary tract : like all types of jaundice except homolytic jaundice.

3. Its level decreases during severe anaemia, scurvy, hypophosphatemia &

cretinism.

5C.10 "Immunoassay"

Immunoassay is a technique for the determination of drugs, hormones and

vitamins and some other compounds at nanogram and still smaller scale. It involves

a reaction between analyte antigen and a specific antibody to give a precipitate or

complex.

1. Antigen :

Antigen is a foreign substance that can induce formation of antibody in the

body and is capable of combining with it. Antigen is a macromolecule like protein,

hormone etc.

2. Antibody:

Antibody is a protein which is capable to recognize a foreign substance & can

have stereospecific association with it. e.g. Virus and bacteria. Globulin protein with

high mol. wt of about 1,50,000 is an antibody. This protein exhibiting activity of

antibody in known as immunoglobulin (Ig) . Five main immunolglobulins in human

blood are IgA, IgD, IgE, IgG and IgM. But, IgG is most abundant. The Ig consists of

three polypeptide clains. Two are of 240 amino acid residues and third of 430 animo

acid residues which are linked through disulphide bridge.

When Ig is treated with papain (an enzyme) three fragments (each of mol. wt

approximately 50,000) are formed. Two are identical and can combine with antigen

and are referred to as Fab – Fragment, antigen binding. Third can't combine with

antigen and is fragment crystallizable [Fc]

It is worth- noting all antibodies are similar in structure but have variable

antigen binding proportions of fab.

Antigen-Antibody association

Antibodies are produced in organism only after organism has at least one

exposure to antigen through vaccination etc. For immunoassay antibody is produced

by injecting antigen into animal and by recovering the serum that contains resultant

antibody. This serum is known as antiserum. Antigen- Antibody reaction gives

antigen-antibody complex. Forces binding them are called affinity. Infact, affinity is

intrinsic association constant between antibody and univalent antigen. Here, is

another term avidity which refers to the overall binding energy between antibodies

and a multivalent antigen.

Overall binding reaction can be written as :

Ab + Ag = Ab.Ag

Formation constant (K)

= ]Ag][Ab[

]Ag.Ab[

Formation constants are of the order of 108-1010. The binding forces are

weak Vender waal force, electrostatic and hydrophobic force. The bonds are broken

by the addition of salts, increasing temperature, pH or polarity of solvent.

5.c10.1 Principles of Radio Immunoassay [RIA]

RIA takes into account sensitivity of radiochemistry , fluorescence and

enzymatic tag with specificity of immunology. Latter is study of antigen-antibody

reaction. Immunoassays [RIA] are based upon the discovery of Rosalyn yalow &

Berson that low concentrations of antigen hormone insulin can be detected

radiochemically due to their ability to combine with radiolabelled insulin (I131). For

this discovery they were awarded Noble Prize in 1977. The determination of

unknown concentration of antigen is based upon the fact that radiolabelled antigen

and unlabelled antigen (from the standard sample) compete physiochemically for the

binding sites on antibodies. For RIA following operations are carried out :

1. Antibody solution (Ab antiserum) labelled antigen (Ag)* and serum sample

containing unlabelled antigen sample to be determined [Ag] are taken is

reaction vessel.

2. Contents of step-1 are incubated as a result of which antigen- antibody

complex [Ag.Ab] is formed. In absence of unlabelled antigens, certain fraction

of labelled antigen [Ag]* bind to give Ag*- Ab. Upon increasing the amount of

Ag, the limited binding sites of antibody are progressively saturated and

antibody binds less of the Ag*.

3. After incubation, bound antigens are separated from free antigens & labelled

portion of either or both phases is measured by measuring radio-activity or

fluorescence in order to determine the percent bound to Ag*.

4. A Calibration curve is prepared using antigen standards of known

concentration by plotting either the percent bound to free as a function of

unlabelled antigen concentration. From calibration curve concentration of

antigen in the sample can be determined .

Drawbacks of RIA

1. Both 125I and 131I emit -radiation which needs special counting equipment .

2. The body concentration of I-atoms radioactive or non-radioactive in thyroid

gland gets incorporated in thyroxin.

Application of RIA

It is an important technique for clinical laboratories & is used in :

1. Determination of plasma levels of :

a. Certain abused drugs

b. Hormones

c. Digitoxin or digoxin is patients receiving these drugs.

2. Anti-DNA antibodies in systemic lupus erythematosus [SLE]

3. Blood banking.

4. Diagnosis of allergies.

5. Presence of Hepatitis B surface antigen in blood.

5C.11 Blood Gas Analysis

Blood gas analysis measures the amount of CO2 in blood as well the

pH(acidity) of blood. It evaluates the efficiency with which lungs are delivering O2

into blood & are eliminating CO2 out side. It also indicates the efficiency with which

lungs & Kidneys are interacting to maintain normal blood pH i.e. acid base balance.

Blood gas analysis in done to access certain disease conditions of lungs & kidneys.

It measures the partial pressure of O2 –contents, O2 saturation, bicarbonate contents

and blood pH. It also indicates how much oxygen is combined with haemoglobin

through the analysis of oxygen saturation which compares the amount of O2

actually combined with haemoglobin to the total amount of O2 which can combine

with haemoglobin.

CO2 dissolves in blood to form bicarbonate and carbonic acid that maintain pH

of blood at which cellular functions go on normally. Lungs and kidneys maintain

balance of carbonic acid and HCO3 in blood, respectively.

Normal Ranges of Blood gas Analysis :

1. Partial pressure of Oxygen = 75-100 mm Hg.

2. Partial pressure of CO2 = 35-45 mm Hg.

3. Oxygen content = 15-23 %

4. Oxygen saturation = 94-100%

5. HCO-3 = 22-26 mEq./lt.

6. pH = 7.35-7.45

Conclusions from blood gas analysis

- Abnormal results indicate respiratory, Kidney or metabolic problems & also

during trauma which effects breathing, results are abnormal specially during

head & neck injuries. .

- Abnormal results are also seen is disorders like anaemia which affects O2

carrying capability of blood & gives abnormally low O2 contents.

5C.12 Trace Elements in the body

Trace elements are found is very small amounts in body but are absolutely

essential for different functions of body. There are seven essential trace elements for

man :

1. Copper 2. Chromium 3. Cobalt

4. Iron 5. Selenium 6. Zinc

7. Iodine

1. Copper (Cu)

Cu is essential part of some enzymes which inactivate free radicals. Thus, it

helps in anti-oxidant protection. It plays role in Iron-Metabolism. Enzymes containing

Cu are involved in immune function. It is used for making blood cells. Increase in

copper contents may lead to liver failure. Its recommended dietary allowance is 2-3

mg which is found in daily multivitamins.

2. Chromium (Cr)

It is needed by cells in the glucose intake process. It's deficiency leads to

increased blood sugar as well as increased cholesterol & triglyceride levels. Yeast,

cheese & meet are chief source of Cr. Its recommended dietary allowance is 50-

200lg. Sometimes, its deficiency is supplemented through multivitamins which

contain 15-100 µg of it. Cr is used up in exercise, infection & injuries etc.

3. Cobalt [Co]

It is a part of Vitamins - B12 .

4. Iron (Fe)

It is part of RBC and have anti-oxidant activity. Fe is frequently used in the

body to prevent its use by bacteria as a source of fuel. Iron gets attached to proteins

& reaches to other parts of body through them. Vitamin-C promotes its functions.

Deficiency of Fe leads to anaemia. Chief sources are liver & red metals.

Recommended dietary allowance is 7-14 mg./day.

5. Selenium (Se)

Se is anti oxidant. It marks immune body function which are like functions of

vitamin-E. Deficiency of Se leads to heart diseases and anaemia. Its deficiency have

also been found in HIV affected persons. Recommended dietary allowance of Se is

approx 50 g from one to four times a day.

6. Zinc (Zn)

Functions of Zn involve the wound healing & maintenance of membranes. It is

also involved in anti-body production. During stess it is shifted from blood to tissues.

Hence, plasma levels do not reflect their actual concentrations. Its deficiency impairs

immune response and causes hair loss. Other diseases like slow proteins

metabolism, diarrhoea, change of taste, loss of appetite, disturbance in absorption,

low levels of testosterone etc have been found in Zn-Deficient persons. HIV patients

also have low level of Zn. Recommended diectony allowance of Zn. is 15 mg.

Multivitamins also contain is 15 mg of Zn.

7. Iodine(I)

It plays important role in the thyroid metabolism. It's supplementation is not

the need. However, iodized salt fulfil the demand.

5 (d) Drug Analyisis

The word 'drug' is derived from French word 'drogue' which means a dry

herb. It may be defined as a substance used in the prevention, diagnosis, treatment

or cure of disease in animals including man.

Characteristics of Drug

1. The action of an ideal drug should be localized at the site where it is desired

to act. However, there is hardly any drug that have this activity.

2. It should be non-toxic.

3. It should have minimum side effects.

4. Drug should not injure host-tissue or physiological process.

5. Drug should be efficient.

6. It should not make the host cells resistant to drug after its use for some time.

However, most of the drugs do not possess this characteristic.

5 d. 1 "Narcotics & Dangerous drugs"

Narcotics is the term used to describe the substances which induce sleep. In

legal context narcotics refer to opium or opium derivatives and their synthetic or

semisynthetic substitutes. Cocaine and Coca-leaves are classified as Narcotics in the

U.S. controlled substances Act. But, they are not narcotics technically. Infact,

narcotic is a broad term; medical professionals use term opiod for natural, synthetic

& semisynthetic substances which are pharmacologically like morphine. These are

also known as narcotic analgesics. Narcotic analysis tends to produce euphoria that

is an important factor in their addictive property which limit their use. Other

limitations include respiratory depression, increased biliary tract pressure, prunities

due to histamine release & decreased gastro-intestinal motility leading to

constipation.

Effects of Narcotics

Effects of narcotics depend upon (i) dose (ii) Mode of administration (iii)

previous exposure to the drug (iv) expectation of the user. Main drawbacks of use of

narcotics are:

1. Drowsiness

2. Inability to concentrate

3. Lessened physical activity

4. Apathy

5. Constipation

6. Constriction of pupils

7. Nausea and vomiting

8. Respiratory depression

9. Dialation of subcutaneous blood vessels leading to flushing of face & neck.

As dose increases, subjective, analgesic and toxic effects become

pronounced. Except the cases of intoxication, there is no loss of motor co-ordination

or slurred speech as with other depressants.

Route of Administration

1. Orally

2. Intravenous (though injections)

3. transdermally (skin patches)

Complications

1. Hepatitis

2. Skin, lungs and brain abcesses

3. Endocarditis

4. AIDS etc.

5. They are habit forming. A chronic drug user needs more & more doses to

attain desired effect like decrease in sedation, euphoria etc.

Withdrawal Symptoms

Withdrawal symptoms from morphine & /or morphine like addictions are

experienced before the time of next scheduled dose e.g.

1. Watering of eye

2. Running nose

3. Yawning & sweating

4. Irritability

5. Restlessness.

6. Loss of appetite

7. Increased heart beat & B.P.

8. Vomiting

9. Tremors and severe sneezing

10. Pain in muscles & back – bone

11.Severe depression

Any time during withdrawal symptom admnistration of narcotic reverses the

symptoms.

Uses of Narcotics

These are used in the treatment of :

1. Pain, acute diarrhoea & cough supression.

2. Reduces tension, anxiety and agression & hence produces sense of well –

being.

Dangerous Drugs

Dangerous drugs are the drugs that are used illegally. Thay are dangerous in

the sense that they cause addition as well as some harmful chemical and physical

effects. Dangerous drugs can cause dangerous behaviour. They are good for none

but are most dangerous for kids and teenagers who are at growing stage. These

drugs can damage brain, heart and other important organs. For example, cocaine

can cause heart attack even to kids & teenagers. Some examples, of most

dangerous drugs are : (i) Methamphetamines (ii) Heroine (iii) cocaine (iv)

Barbiturates (v) LSD (vi) Benzodiazepine (vii) Marijuana (viii) opium (ix) caffiene &

nicotine (x) Hashish.

5d.2 "Classification of Drugs"

Most important classification of drugs is on the basis of their therapeutic

actions. On this basis they are classified into two main classes:

1. Chemotherapeutic agents

2. Pharmacodynamic agents

(1) Chemotherapeutic agents

These drugs are used to cure specific diseases like microbial infections,

maleria, tuberculosis, syphillis etc. Chemotherapeutic agents attack and destroy the

invading organisms without any adverse effect on infected organism. Chemotherapy

is defined as the treatment of diseases by chemicals which selectively inhibit the

growth of infecting organisms. First chemotherapeutic agent was an anti-syphillis

agent discovered by Ehrlich (1910). This class has been divided into following types :

(i) Antibacterials

(ii) Antimalarials

(iii) Antiprotozoals

(iv) Antifungals

(v) Antiseptics

(vi) Anthelmintics

(vii) Antineoplastic agents

(viii) Antitubercular & antileprosy drugs.

(ix) Organometallic therapeutics

(2) Pharmacodynamic agents

These drugs have characteristic action on infected organisms but are not

specific remedies for particular disease. These drugs are further classified into

following classes:

1. Anaesthetics

2. Sedative, Hypnotics, Anticonvulsants

3. Tranquillisers.

4. Antipsychotic drugs.

5. Anti-anxiety drugs.

6. CNS (Central nervous system stimulants)

7. Pschotogenic drugs.

8. Hypo and Hypertensive agents.

9. Anti coagulants

10. Adrenergic stimulants

11. Cholinergic & anti-cholinergic agents.

12. Diureties

13. Antipyretics and analgesics.

14. Antispasmodics

15. Anti-histamines

16. Anti-inflammatory drugs

The medicinal value of a drug is expressed in "therapeutic index" which is the ratio

of amount necessary to kill the patient i.e. maximum tolerated dose to maximum

curative dose.

dosecurativeMaximum

dosetoleratedMaximumindexcTherapeuti

The therapeutic index of 10 indicates that 10 times of the dose used for

curative purpose will kill the patient as well as to the parasite. Some important

classes of both the major classes are being discussed here:

(1) Anti-bacterials : These are of two types:

(A) Sulpha – drugs

(B) Antibiotics

(A) Sulpha drugs [Sulphonamides]: Sulpha drugs are derivatives of

sulphanilamide. These were first synthetic compounds effective against

bacteria that cause pneumonia, tuberculosis, gonorrhoea, diptheria, scarlet

fever etc. Some examples are: sulphathiazole, sulphate acetamide,

sulphapyridine etc.

(B) Antibiotics : An antibiotic is a compound produced by one micro-organism

which is toxic to other micro-organism. Some examples are penicillin,

streptomycin, tetracyclins, chloramphenicol etc.

(2) Antimalerials : They cure malaria caused by malaria parasite plasmodium

vivax & others. e.g. Quinine, chloroquine, camoquine, pamaquine, paludrine

etc.

(3) Antifungals : Anti-fungals cure fungal infutions in animals and plants. e.g.

Clotrimazole, salicylic acid etc.

(4) Antiseptics : Antiseptics may kill bacteria or may only prevent their

multiplication. They do not harm living cells hence are used on cuts &

wounds. Few examples are : Dettol, savalon, gentian violet, acriflavin,

mercurochrome, KMnO4, boric acid etc.

(5) Anthelmintic : They kill worms e.g Ascaridol.

(6) Antineoplastic: Thes are anticancer e.g fluoroceracil.

(7) Antitubercular and anti-leprosy drugs: Anti-tubercular drugs are used to

cure tuberculosis-e.g. streptomycin, para-amino salicylic acid (PAS), isoniazid.

Anti-leprotic agents are used in the treatment of leprosy caused by

Mycobacterium leprae, e.g. sulphones like dapsone [DDS].

(8) Organometallic Therapeuties : Examples of organometellic therapeutic

agents are Atoxyl, stovarsol. Generally they are effective against protozaon

infections.

(9) Anaesthetics : The term anaesthetics is derived from Greek word,

anaesthesia means insensibility. Hence, anaesthetics may be defined as drugs which

bring about the insensibility to the vital functions of all types of cells specially those

of nevous system. Anaesthesia are of two types :

(A) General Anaesthetics: These anaesthetics depress CNS to such an extent

that all the sensitivity to pain or feeling is lost. They cause unconsciousness

all over the body e.g. Halothene, Pentothal sodium.

(B) Local Anaesthetics : Instead of affecting the whole body, these

anaesthetics make a particular organ insensitive e.g. Banzocaine, procaine

(10) Sedative, Hypnotic and Anti-convulsants:

These are non-selective CNS modifers i.e. antidepressants.

- Hyprnotics are CNS depressants that produce sleep resembling the natural

sleep. e.g. Luminal

- Sedatives are CNS- depressants that reduce nervous tension and promote

relaxations without producing sleep. e.g. Diazepam

Anticonvulsants are those CNS depressants which prevent or supress convulsions.

Thus, these three differ only in degree of action. Large amount of hypnotics

may produce anaesthesia & even death in some cases.

(11) Tranquilizers: These drugs are used in the treatment of mental disorders.

These are mood elevators and restore peace of mind without producing sleep.

e.g. Amphetamin.

(12) CNS-Stimulants : These drugs stimulate central nervous system and are

anti-depressants. e.g. Amphetamine.

(13) Psychotogenic drugs : They induce behaviourial abnormalities resembling

psychosis. e.g. LSD [Lysergic acid diethyl amide] & mescaline [3,4,5-

trimethoxyphenyl ethylamine].

(14) Hypo and Hypertensive agents : Hypotensive agents increase B.P. &

hypertensive elvevate it e.g. methyldopa is used in hypertensions & reduces

B.P.

- Sodium nitropruside is short acting hypotensive agent & is mostly employed

as vasodialator in emergency treatments of hypertensive crisis.

(15) Anticoagulants : Anticoagulants are the substances that interfere with blood

coagulation thus prolong coagulation time. e.g. Heparin & warfarin (a

coumarin derivative).

(16) Adrenergic & Cholinergic agents : The drugs that mimic stimulation of

sympathetic nerve are called adrenergic drugs and the compounds that mimic

the parasympathetic system are known as cholinergic drugs. Examples: are

Adrenaline and ephedrine of former and Acetylcholine and Muscarine of latter.

(17) Diuretics: compounds that increase urine volume output by kidneys are

called diuretics e.g. Caffeine, Acetazolamide.

(18) Antipyretics and Analgesics : Antipyretics bring down body temperature

and analgesics provide relief from pain. e.g. Aspirin, paracetamol.

(19) Antispasmodic Agents : Control contraction of muscles. e.g. Khellin.

(20) Antihistamines : They also control contraction of muscles. e.g. Phenargan

(promethazine).

(21) Anti-inflammatory agents : They are used against swelling and

inflammation. e.g. during arthritis. Examples are : Phenylbutazone, oxy-

phenylbutazone etc.

5d.3 "Screening of Drug by Gas & Thin-layer chromatography and

spectrophotometric measurements"

Analysis of drugs is being discuss ahead under following three heads.

(i) Spectrophotometric determinations

(ii) Thin-layer chromatographic (TLC) determinations

(iii) Gas chromatographic determinations.

5d. 3.1 Spectrophotometric determinations (UV/VIS)

Ultraviolet and visible spectrophotometry is a technique for the quantitative

estimation of compounds and is also an auxillary tool for structural elucidation.

Ultraviolet-visible region extends from 185-760 nm. Range of UV region is 185-400

mm & visible region is from 400 to 760 mm. Only coloured compounds absorb in

visible region & colorimetry is concerned with the visible region of spectrum.

In spectrophotometric analysis a source of radiation is used which gives

radiation of 180-400 nm & the instrument used is known as spectrophotometer. But

is colorimetric analysis determination of quantity of substance is made on the basis

of colour changes which depends upon concentration of substance. The instrument

used for colorimetric analysis is known as colorimeter.

Advantage of colorimetric and spectrophotometric methods is that very

minute quantities of substance present is solution can be determined by them.

Upper limit of colorimetric determinations is less than 1 or 2%

Wave lengths of colours

Violet 400-450 nm Yellow 570-590 nm

Blue 450-500 nm Orange 590-620 nm

Green 500-570 nm Red 620-760 nm

In colorimetry colour may be either due to constituent itself or may be

produced by the addition of suitable reagent & intensity of colour may be compared

with that obtained by treating a known amount of substance in the same manner.

Principles of spectrophotometry and colorimetry

When a monochromatic or heterogeneous beam of light falls on a

heterogenous medium, a part of incident light is reflected, a part of it is absorbed

within the medium & rest of it is transmitted. If the intensity of incident light is Io,

that of absorbed light Ia & transmitted light is It & reflected light is Ir.

I0 = Ia + It + Ir

Absorption of light depends upon thickness of medium & is governed by

Beer's & Lambert's laws which are :

According to Lambert's law

kII

I

t

0ln

or It = IO. e-KI

or KIt

I

I 100

o

t

I

I is the fraction of incident light transmitted by thickeness l of the medium

as is known as Transmittance(T).

t

0

I

I = opacity

Absorbance of the medium A also known as optical density D or Extinction

is given by formula :

t

0

I

IlogA

According to Beer's Law :

It = Io. e-Kc.

= Io. 10-acl

or t

0

I

Ilog = acl

combined Beer-Lambent law is :

clI

I

t

0log

or = A/cl

Instrumentation

Instrumentation of U.V.-visible spectroscopy is discussed ahead. Essential

Features of simple filter colorimeter are : (i) Light source (ii) filter to select suitable

wave length (iii) cuvettes (iv) photocell to receive transmitted light (v) a meter to

measure the response of photocell.

Double Beam Spectrophotometer

Modern UV-Visible spectrophotometer are double beam type & cover the range 200-

800 mm. In these instruments a monochromatic beam of light from tungsten-

deuterium lamps is divided into two identitical beams, one of which is allowed to

pass through reference cell and other through sample cell. The absorption through

reference cell is automatically subtracted from sample cell by the instrument & net

signal corresponding to absorption for the component is recorded.

The splitting and recombination operations on beam are carried out by two

rotating sector mirrors which are geared to same electric motor so that they work in

unison. The microprocessor which operates the instrument automatically corrects

the dark current of photocell.

Origin of Absorption Spectra

UV-Visible spectra are obtained as a result of excitation of electrons to higher

energy levels. Lower energy excitations show absorption in visible region whereas

higher energy excitations give absorption bend in UV-region. Electronic energy

changes are accompanied by vibrational energy changes i.e. why instead of sharp

absorptions lines, broad absorption bands are obtained. Absorptions are of different

types : - *, n - *, - *, n - *. These are responsible for different absorption

bands.

Preparation of Standard Curve

When determinations are made by using spectrophotometer or filter

photometer, it is essential to prepare standard curve, also known as calibration

curve or reference curve, for the constituent to be determined. For it, determinations

for suitable quantities are made in the same way as for the sample by measuring

absorbance (or transmittance) at optimum wave length. Preferably absorbance (

t

o

I

Ilog ) is plotted against the concentration & a straight line is obtained if Beer's Law

is obeyed. When absorbance is directly proportional to concentration few points are

needed to prepare the line, but if relation is not linear greater number of

determinations are needed to be done to get the line. In case, filter photometer is

being used characteristics of light source as well as filter may change with time.

While using transmittance, transmission of 100% is assigned to blank solution

(reagent & water) which represents Zero concentration of the substance to be

estimated. It is worthnoting that few coloured solutions have appreciable

temperature co-efficient of transmission, therefore, temperature should remain

constant through out the determination.

Selection of Solvent

To be a good solvent during spectrophotometric or colorimetric estimations it

should have following characteristics :

(i) It should be a good solvent for the constituent to be determined.

(ii) It should not react with the substance.

(iii) It should not absorb at the wavelength used in determination.

For inorganic substances water is the best solvent. But, for organic

estimations organic solvent is needed. Polar organic solvents like alcohols, ketones,

esters water etc suffer from drawback that they obliterate fine structure of spectrum

due to vibrational effects. Therefore, hydrocarbons like cyclohexane (e.g. in case of

phenol) give better spectrum with three sharp peaks as compared to water in which

a single broad band is obtained. Wavelengths of absorption of some good solvents

are given below:

Solvent nm Solvent nm

Water 190 Cyclohexene 212

Hexane 199 Dichloromethene 247

Heptane 200 Chloroform 257

Diethylether 205 Benzene 280

Ethanol 207 Pyridine 306

Methanol 210 Acetone 331

Methodology of UV-Visible spectrometric & Colorimetric Determination

(I) Cells should be washed with distilled Water

If solvent used is not miscible with distilled water after use cells should be

washed with that solvent thoroughly. Finally they are rinsed with ethanol & dried.

Drying may be done in vaccum desiccator also. The cells which have become

contaminated may be cleaned with detergents like teapot followed by proper drying.

(II) Preparation of Solutions

All the solutions needed should be prepared accurately. In UV-instruments

direct measurements may be made without adding reagents. Solutions which are

unstable should be prepared the moment, they are to used. The test solution should

be dilute to the extent that absorbance lies is the region 0.2-1.5, otherwise they

should be further diluted.

(III) Calibration Curve Preparation

Calibration curves are plotted by measuring absorbance at 5.0, 7.5, 10.0 and

15.0 ml of standard solutions which are diluted to 100 ml in graduated flasks &

plotting them against concentrations. But, if same estimations are routine procedure,

already prepared calibration curves may be used.

(IV) Calculation of Concentration of Unknown Solution

During UV measurements concentration of unknown solution is calculated by

the formula :

Molar extinction coefficient () = A/cl.

Where, A = Measured absorbance of solution at concentration C.

l = Path length.

During few measurements is unknown (e.g. during natural product

measurements) because relative masses are unknown; then cmE1

0/10 value is used

which is the absorptivity.

Experiment

Estimation of phenacetin, caffeine and Aspirin in the given mixture of drugs.

Principle

A mixture of phenacetin, caffeine and Aspirin may be analysed quantitatively

by UV spectrophotometric method. Phenacetin shows absorption maxima ( max) at

250 nm, caffeine at 275 nm and aspirin at 277 nm. First they are separated & then

analysed spectrophotometrically :

Chemicals Required :

(i) Dichloromethane (CH2 Cl2)

(ii) 4.0% NaHCO3 Chilled

(iii) Conc. HCl

(iv) 1M – H2SO4

Preparation of Standard Solution

Standard solution of each drug is prepared in CH2Cl2. The concentration for

solution are 10 mg/lt for caffeine, 20 mg/lt for phenacetin & 100 mg/lt for aspirin.

They may be prepared by dissolving 25 mg of each drug in 100 ml of CH2Cl2 &

diluting 1 ml and 2 ml of these solution in 25 ml measuring flask to get 10 mg/lt &

20 mg/lt of solutions. As aspirin decomposes in the solution, hence, its solution

should be prepared just before using it.

Methodology

Accurately weigh about 400 mg. of tablet in a beaker. Add to it 20 ml of

CH2Cl2 and transfer the solution to 60 ml separatory funnel. Extract aspirin from

CH2Cl2 extract with two 10ml portions of chilled 4.0% NaHCO3 solution. Add to

extract 5 ml water containing two drops of HCl. Wash the extract with three 10 ml

portions of CH2Cl2 & add the washings to original CH2Cl2 layer. Leave the aqueous

extract is separatory funnel.

Now filter the CH2Cl2 solution through the filter paper impregnated with

CH2Cl2 in a 50 ml volumetric flask & make up the volume.

Acidify NaHCO3 layer with 6 ml 1M-H2SO4 solution to avoid hydrolysis of

aspirin. pH at this point should be 1-2. Extract this acidified solution with eight

separate 10 ml portions of CH2Cl2 and filter through filter paper already impregnated

with CH2Cl2 in a 100 ml volumetric flask and make up volume upto the mark. Now,

dilute 5 ml of this solution to 25 ml with CH2Cl2 in a volumetric flask [Ca: 25 ml].

Record the absorbance of this solution on at 277 nm. Absorbance of standard

solutions of aspirin is recorded under exactly same conditions at 277 nm from which

concentration of aspirin in given mixure of drugs can be calculated. Concentration of

aspirin is used to calculate its percentage.

Similarly, concentrations and hence percentages of phenacetin and caffiene in

the tablet (mixture of drugs) can be determined at 250 and 275 mm, respectively.

Result

Given tablet is a mixutine of drugs : .......................% Aspirin;

.........................% phenacetin and ......................% caffeine.

5 (d)3.2 "TLC – Determinations"

This Layer Chromatography (TLC)

(i) In this technique separation of components of mixture or identification of

organic or inorganic compounds is made on a thin film of adsorbent which

acts as stationary phase. Adsorbent adheres to glass plate by virtue of its

binding ability, for instance, calcium sulphate which is incorporated acts as

a binding agent. This film prepared on glass is known as Chromaplate. As

this technique uses thin film of adsorbent that is why it is known as thin

layer chromatography (TLC). Some workers call it spread column

chromatography, open column chromatography or surface

chromatography.

TLC – Technique

Infact TLC is adsorption chromatography and is based upon the difference in

adsorption of the components of mixture on the adsorbent. Distribution coefficients

of components between stationary and mobile phase play an important role in TLC –

separations. Stationary phase in TLC is adsorbent coated on glass plate and mobile

phase is the solvent system which moves on adsorbent thin layer. On the basis of

difference in adsorbitivity different components get adsorbed at different distances

and are hence separated. The process by which different components move upward

through continuous flow of mobile phase is known as elution and solvent is known

as eluents. The components which move upward are known as eluates. Entire TLC

technique can be studied under following steps:

(i) Selection of adsorbent

(ii) Preparation of TLC plates

(iii) Choice of solvent

(iv) Application of sample

(v) Development of plates

(vi) Location of spots

(vii) Determination of Rf.

(1) Selection of Adsorbent:

While selecting adsorbent polarities of sample to be separated or purified and

that of solvent should be matched. Adsorbent should be completely insoluble in

solvent. The particle size should be 200-300 mesh. Adsorbent should not enter in

chemical reaction with sample as well as solvent. Earlier, silica gel, alumina (basic)

and neutral Kieselghur were used as adsorbent. But, now a days a number of

materials are available (with or without fluorescent compound) liked ZnS to view

compounds under U.V. lights for this purpose.

(2) Preparation of TLC Plates (Preparation of chromato plates)

Before coating glass plates with adsorbent they should be properly cleaned

with laboratory detergents using test-tube brush to remove adhering particles and

washed thoroughly with distilled water. Plates should be allowed to drain and dried

in oven. Plates should be handled from edges or the side which is not to be coated.

Otherwise a mechanically unstable layer is formed. If glass plates have some greasy

material over them, they should be cleaned with chromic acid. Generally 20×5 cm

glass plates or microscopic slides are used to prepare chromatogram.

First, glass plates of even thickness are selected. A slurry of adsorbent in

suitable solvent is prepared. For example, 25g silica gel containing 13% plaster of

paris is made into slurry in 50 ml of distilled water by slow addition and stirring with

glass rod or spatula. Then a thin coating of this slurry is applied on glass plates by

means of spreader. The slurry is transfered immediately to spreader which is pulled

across with uniform motion over row of glass plates of even thickness. Thickness of

thin layer of adsorbent is controlled with the help of clearance by the means of two

screws present. Generally a layer of 0.25 mm thickness is suitable.

Alternatively, slurry may be prepared in dichloromethane also. For instance,

30g of adsorbent (usually silica gel or alumina) are slowly added to 100 ml of dry

dichloromethane contained in wide mouth bottle with continuous stirring and bottle

is capped. For preparing the plates pair of microscopic slides is held together and

dipped in slurry, then slowly taken out and allowed to drain for a while over the

mouth of bottle. Slides are separated carefully, placed horizontally and allowed to

dry for 10 minutes. Adsorbent lying on the edges of slides is removed wih the help

of a razor.

After coating and drying plates are activated in oven at 1100C for half an

hour. Cellulose and polyamide plates are allowed to dry at room temperature and

stored in dust-free cabinet; they don't need activation.

(3) Choice of Solvent

Choice of solvent depends upon the nature of sample to be separated as

well as nature of adsorbent. In adsorption chromatography polarity of solvents

follow the following order (Increasing order):

Petroleum ether (or hexane) > carbon tetrachloride > Benzene (or toluene) >

Dichloromethane > chloroform > Diethylether > Dimethyl formamide > Ethyl

acetate > Pyridine > Acetone > Ethanol > Methanol > Formamide > water >

Glycerol.

Generally, polarities of sample and solvents are matched and then choice is

made. More polar solvents make more migration and give better separation. A

combination of two solvents also gives better separation as compared to single

solvent. Best position of the spot of compound is half way between line and solvent

front.

(4) Application of Sample

1-3 mg of substance is dissolved in 0.1-0.6 ml of a solvent in which it

dissolves well and which evaporates rapidly. Dichloromethane, diethylether,

chloroform or light petroleum are best for this purpose (b.p.- 40-600c). Quick

evaporation gives smaller spot which results in better separation of components in

chromatographic development. Thin end of TLC capillary spotter is dipped in the

solution which rises in the capillary. About 1 microlitre of the solution is applied on

the already marked base line which is at a height of 1-20 mm from the bottom of

chromoplate just by the touch of fime end of TLC spotter. A finish line is also marked

at about 10 cm from base line. Size of the spot applied should be as small as

possible (1-3 mm) and if the solution is very dilute first this spot is allowed to dry

and solution should be applied twice or thrice to make up the concentration. Each

time size of the spot fromed should be same. Finally, spot may be dried in hot air.

Base line may also be marked by making a small notch which help in making the

measurements at the later stage.

Notch at starting line

capillary

Finish line Adsorbent Base line

Glass plate

Fig: Putting a spot of substance on TLC- Plate

(5) Development of Plates

Chromoplate of 20 × 5 cm. size may be developed in cylinderical glass jar.

Rectangular plates of 20 ×10 cm may require a rectangular glass tank of appropriate

dimensions. But microslides can be developed in 150 ml beaker or in a wide

mouthed screw-capped glass bottle. Inside any of the above mentioned chambers is

lined with filter-paper leaving a gap to view chromoplate. Filter paper is saturated

with chosen solvent system for developing the plates by closing the jar containing

solvent system and filter-paper for 10 minutes.

A nonpolar eluent (solvent) forces nonpolar compound upwards, whereas

polar eluents force both polar as well as nonpolar substances upward. These facts

help in choosing the solvent system. Properly choosen solvent system is taken in the

chamber upto the height of approximately 1 cm only; thins is enough to saturate the

environment of chamber as well as to stop the evaporation of eluent from the plate.

Spot of the plate should always be above the level of eluent, otherwise spot will

dissolve in solvent. In such a event throwing away of the solvent and cleanring of

the chamber will be required and fresh plate will be needed for running TLC. Thus,

spotted TLC plate is placed inside the saturated chamber in slanting position in such

a way that spot is above the level of solvent for the purpose of development and

eluent is allowed to run up to finish line. When solvent reaches the finish line plate is

immediately removed. Solvent is drained and air is blown over the plate to help

evaporate the solvent so that plate becomes dry. Precaution is taken that elvent is

not enhaled.

(6) Lacation of Spots: Following locating agents can be used for the the

visualization of spots :

(i) Iodine : Iodine forms coloured and loose complexes with a number of

compounds. Iodine can be used for visualization either by spary of

iodine is an organic solvent or by placing the developed plate in

chamber containing iodine vapours for 1-5 minutes. This can locate a

number of compounds but not all the compounds present in mixture.

(ii) Concentrated sulphuric acid : Concentrated sulphuric acid alone or

a solution of concentrated sulphuric acid (4 ml) in methanol (100 ml)

spray also gives good results. After this spray plate is heated in oven to

about 2000C until organic compounds appear as charred spots. Most of

the components become visible by this method.

(iii) It has been found that sulphuric acid mixed with aromatic aldehydes,

powerful oxidising agents like potassium permanganate, chromic acid,

nitric acid and ceric sulphate also give good results.

(iv) Other spray reagents like potassium permanganate (2%) in aqueous

solution of sodium hydrogen carbonate (4%) or phosphomolybdic acid

(10%) in ethanol may also be used.

(7) Determination of Rf

Retention factor or Rf value which is characteristic of compound in a

particular solvent system can be determined by the formula :

Rf = lineorigin fromsolvent by travelledDistance

lineorigin fromcomponent by travelledtanceDis

As distance moved by solvent (i.e. solvent front) is always more than that travelled

by component, Rf is always lesser than one. It is worth noting that Rf is constant for

each component under identical conditions. Following factors affect Rf value :

(i) Quantity of adsorbent used

(ii) Thickness of adsorbent layer

(iii) Activation grade of adsorbent

(iv) Quality of solvent

(v) Particle size of adsorbent

(vi) Saturation of chamber by solvent vapours.

Precautions during TLC:

1. Spot should not be too concentrated otherwise spot will smear out. If this

happens spotting solution should be diluted.

2. Spots should not be too close to each other otherwise spots start bleeding

into each other and it becomes difficult to tell which spot came from which

origin.

3. Spot should not be close to edge, otherwise inaccurate Rf Value is obtained.

As such a spot is not surrounded much by adsorbent and solvent, unequal

forces work which donot give proper separation.

Exercise : Analysis of drug samples through TLC :

Preparation of Sample

Take 125 mg of sample in a test tube and dissolve it in 4 ml of metharol-

toluene (1:1) solvent system. Reference standards are prepared of strength 25

mg/ml.

Samples like cocaine, heroin & methamphtamine may be used.

Application of Sample Commercially prepared fluorescent silica gel TLC – plates

may be used which are coated on plastic sheets of 8.5×3.5 cm dimensions. These

plates have been activated at 1200C for 20 minutes. All the four solutions [three

references and one unknown] are carefully spotted on a single plate. Distance

between two spots should be about .75 cm. Spots should not be larger than 2-3

mm.

Development of chromatogram

Plate is placed in solvent system [prepared from Toluene [60 ml] + ether (30

ml) + CH3COOH (9 ml) + MeOH (0.5 ml)] about 5 ml of which is contained in TLC

chamber. Chromatogram is developed till solvent reaches about 1 cm below the top

of the plate. Remove the plate immediately & mark the solvent front. Allow the plate

to dry. A hair-drier speeds up solvent evaporation process.

Visualization : Colourless spots are visualized by illumination of plate under U.V.

lamp. Generally, aromatic compounds show bright fluorescence with characteristic

colour. TLC-plates contain traces of fluorescent dye. Fluorescent compound show

bright spot on light background, others show dark. spots since they quench to

fluorescence of background dye Spots are encircled with a pencil & their colours are

noted. Visualization may also be done with I2 placed in a chamber. Plates may be

placed in I2- chamber for 1-2 minutes.

Observation & conclusion :

1. Rf values of all the spots are calculated.

2. From the number, positions & appearance of spots in reference compounds, the

identity of unknown compounds may be determined.

5d. 3.1 "Gas Chromatographic Determination"

(Drug Screening using Gas chromatography)

Drug screening can also be done using Gas chromatograph [e.g. Perkin Elmer

gas chromatograph] or through GC/MS. GC/MS have gas chromatograph combined

with mass spectrometer. Here separation of sample is done using gas as an eluent

moving over adsorbent filled column. An example of such identification is discussed

below:

A gas chromatograph of blood plasma extract from drug over dose of a

patient may contain two peaks. One of which matches retention time of glutethimide

(1). The GC/MS mass spectrograph show a peat at M/z 217 corresponding to mol

wt. of this compound (1). Several other peaks are also present due to fragmentation

of molecular ion [M+ = 217]. These observations identify glutethimide in sample.

- Retention time of peak-2 does match with drug. But, mass spectrum of this

compound shows M+ at m/z 233 i.e. 16 mass unit higher than drug. This indicates

presence of a metabolite differing 16 mass unit higher from drug in sample. This

compound may be 4- hydroxy metabolite which is also indicated by the presence of

fragments in mass spectra of two compounds.

Check your Progress – VI

Notes :

(a) Write your answers in the space given below.

(b) Check your answers from the key given in the end.

(i) Narcotics are habit-forming True/False

(ii) Anti-neoplastic agents are used to cure ..................

(iii) What is Therapeutic Index.

(i) ............................................

(ii) ............................................

(iii) ............................................

............................................

............................................

............................................

5.2 Let us Sum up

Our objective was analysis of various components of soil, fuel, body liquid as

well study and identification of various drugs as they all are integral part of our life.

Study can be summarized through following points:

Soil is a natural medium for the growth and development of plants & it

provides mechanical support to vegetation. Hence, presence of essential

components Viz. moisture, nitrogen, phosphorus, silica, lime, magnesia, manganese,

sulphate and alkali metal in proper proportions should be in it as required for

growing the particular plant. If they are deficient it particular ingredient it should be

added. Further more few plants grow well in acidic soil while others in basic soil,

hence, pH of soil is important which should be maintained by adding fertilizer or lime

to it. Each ingredient mentioned above play important role is plant metabolism Thus,

analysis and maintenance of soil is of utmost importance.

Methods of analysis of each constituent of soil are discussed is unit 5a.

Moisture can be determined gravimetrically as well as volumetrically. For the

determination of pH- electrical pH- meter method is best. Total nitrogen can be

determined by autoanalyser. Olser method is generally used for the estimation of

phophorus. Lime is determined by Shoe maker method & Mg by EPTA-titration. Mn-

can be estimated spectrophotometrically and sulphur by Palaskar et al. method.

Fuel is essential to fulfill energy needs for different purposes like:

(i)cooking (ii) Transport (iii) Industrial (iv) Space vehicles

- Characterization of fuel is necessary to choose good quality fuel for which (i)

Proximate analysis & (ii) Ultimate analysis are used. Furthermore, fuel can be

solid, liquid or gaseous. Among solid fuels coal like anthracite & charcoal are

widely used. Important liquid fuels are diesel & petrol. Liquid fuels are

characterized by the determination of calorific value, flash point and aniline

point.

- Gaseous fuels like LPG, natural gas, producer gas and water gas are widely

used.

- Fuels are characterized by ultimate analysis and proximate analysis, former

estimates elements C, H, N1, S1, O & ash. But latter determines (i) moisture

contents (ii) volatile carbonaceous matter (iii) Ash (iv) fixed carbon.

Anti-Knocking property of gasoline (petrol) is expressed in octane number.

Clinical chemistry is related to the study of chemical aspects of human health.

For proper metabolism which is essential for good health all ingredients of body

should be in normal range. Their concentration in blood, plasma, serum etc are

determined chemically and spectroscopically. Different methods of analysis which

help is the diagnosis have been described in unit 5(c). Preservation and collection

methods related to blood, plasma and serum have been described. For preservation

blood anticoagulants like heparin are added. Immunoassay and principle of

redioimmunassay have been discussed.Later is based on antigen-antibody reaction

to give complex which can be estimated spectrophotometrically.

Blood gas analysis is done to check respiratory & kidney diseases. It also

indicates pH of blood is 7.33-7.45.

Subunit 5d. deals with the study and screening of drugs. Dangerous and

narcotic drugs have been differentiated. Classification of different drugs have been

done on the basis of their therapeutic actions into

(i) Chemotherapeutic agents.

(ii) Pharmacodynamic agents.

21-sub-classes of these two main classes have been described with examples

of each. Screening of drugs through spectrophotometric and chromatographic

methods (Gas & TLC) have been described.

5.3 Check your progress : ........... The Key

(I) (i) Yes

(ii) False

(iii) Lime

(II) (i) Olsen method

(ii) See 5a. 8 [Importance of Mg]

(iii) Chlorolysis

(III) (i) True

(ii) CO + H2

(iii) It will be consumed.

(IV) (i) Carbon, Hydrogen, nitrogen, sulphur and ash.

(ii) See determination of aniline point in the unit.

(iii) High.

(V) (i) Oxy-haemoglobin

(ii) These are anti-coagulants

(iii) See RIA in unit 5(c).

(VI) (i) True

(ii) Cancer

(iii) See Therapeutic index in unit 5d [classification of drugs]

5.4 References

1. Sharma, B.K; Engineering Chemistry, Krishna Prakashan India (P) Ltd,

Meerut (1999)

2. Jackson, M.L; Soil chemical Analysis, Prentice Hall of India, Pvt. Ltd., New

Delhi (1973)

3. Chopra S.L., Kanwar J.S., Analytical Agricultural Chemistry, Kalyani Publishers,

New Delhi, Ludhiana (1991).

4. Hesse, P.R., Soil Sampling and Methods of Analysis, CBS- Publisher &

distributors, New Delhi (1994).

5. Evett S.R., Encyclopedia of water science, Mercel Decker (2003).

6. Gartley, K.L., Recommended Soil Testing Procedures for the North Eastern

united state (2011).

7. Finar, I.L., Organic Chemisty, Vol. I, ELBS.

8. Fieser, L. & Fieser, M., Organic chemistry.

9. Roger's Manual of Industrial Chemistry, Vol I & Vol II

10. Price, C.P. and Newmann, D.J., Principles and Practice of Immunoassay,

Macmillan (U.K.) [1997]

11. Samson Wright's Applied Physiology, Revised by Keele, C.A. and Neil, E.,

ELBS.

12. Cooper & Gunn's Tutorial Pharmacy, Ed. by S.J. Carter, CBS Publishers &

Distributors, New Delhi (2000)

13. Kar, A., Medicinal Chemistry, New Age International (P) Ltd., New Delhi

(2000)

14. Gupta, A., Analytical Chemistry, Pragati Prakashan, Meerut (India) (2009)

15. Agarwal O.P., Synthetic Organic Chemistry, Goel Publishing House, Meerut

(India) (1999).

Books Suggested

1. Analytical Chemistry, G.D. Christian, J. Wiley.

2. Fundamentals of Analytical Chemistry, D.A. Skoog, D.M. West and F.J. Holler,

W.B. Saunders.

3. Analytical, Chemistry-Principles, J.H. Kennedy, W.B. Saunders.

4. Analytical Chemistry- Principles and techniques, L.G. Hargis, Prentice Hall.

5. Principles of Instrumental Analysis, D.A. Skoog and J.L. Loary, W.B. Saunders.

6. Principles of Instrumental Analysis, S.M. Khopkar, Wiley Eastern.

7. Quantitative Analysis. R.A. Day, Jr. and A.L. Underwood, Wiley Eastern.

8. Basic Concepts of Analytical Chemistry, S.M. Khopkar, Wiley Eastern.

9. Handbook of Instrumental techniques for analytical Chemistry, F. Settle, P.H.