DERIVATIZATION OF GAS CHROMATOGRAPHY & COMPARISION OF GAS CHROMATOGRAPHY & HPLC

GUDIED BY:

Mr. UTTAM PRASAD PANIGRAHY

PRESENTED BY:

M.Srilatha

Pharmaceutics

COMPARISION OF GC&HPLC

GAS CHROMATOGRAPHY In this technique a stream of

carrier gas that act as mobile phase is passed over a fixed stationary phase placed inside the column.

Principle:- GLC=Partition chromatography. Gsc=Adsorption

chromatography

HIGH PERFORMANE LIQUID

CHRROMATOGRAPHY In this technique a

liquid mobile phase is pumped at a high pressure through a suitably modified column that acts as a stationary phase.

Principle:- separation in HPLC is adsorption.

Depending upon the nature of stationary phase used.

1) Gs-liquid chromatography:

Mobile phase-Gas Stationary phase-Thin

layer of non-volatile liquid or a polymer coated innert solid

Ex;Porous polymer, sand glass beads.

2)Gas-solid chromatography:-

Mobile phase-Gas Stationary phase-solid

adsorbent Ex; silicon rubber,poly

ethylene glycol

Techniques of HPLC are classified based on

I. Modes of chromatographyII. Normal phase mode:- Mobile phase-Non polar-Ex; hydrocarbon solvent alcohols. Stationary phase-silica gel3)Reverse phase mode:- Mobile phase-polar-Ex; methanol with water aqueous

buffer Stationary phase-non polar-Ex; alcohol chlorinated, solvents.

2)HPLC-principle of separation:-

1. Adsorption chromatography:- Adsorption2. Ion- exchange chromatography:-Reversible

exchange of ions.3. Gel permeation chromatography:-Molecular filtration4. Affinity chromatography:-Affinity of analytic towards

stationary phase

3)Elution technique:- Isocratic separation Gradient separation4)Scale of operation:- Analytical HPLC Pre-operative HPLC5)Type of analyse:- Qualitative analysis Quantitative analysis

The concept of gas chromatography between 1941&’1943

Instruments used are simple, less expensive.

Equipment cost is 8 lacks above

pore size- Gaseous and volatile

compounds can be easily separated and analysed

The concept of the HPLC between 1967&’1969

HPLC columns are expensive&eqiupment cost is high.

Equipment cost is 15-20lacks above

Pore size-3-10µm Gaseous and volatile

compounds cannot be easily separated and analysed

Thermo stable compounds

can be analysed

Preparation of mobile phase is easy. Ex;H2gas

Mobile phase cannot be recovered

It requires temperature programming.Ex;Linearmode

Samples need to be heated at elevated temperatures. If it is not in the gaseous state

Ex;Thermostable

Thermo labile compounds can be easily separated and analysed

Preparation of sample and solvent is laborious& time consuming process.

Mobile phase can be recovered

Temperature. programming is not essential

Sample treatment is not required when aqueous or non aqueous samples are to be analysed

Instrumentation

includes:-a) Gas supply unitb) Sampling unitc) Columns unitsd) Injection devicee) Detectorsf) Recorders Precolumn is not

required.

Instrumentation includes:-

a) Solvent delivery systemb) Injectionc) Columnsd) Analytical columnse) Solvent degassing

gradient controllerf) Detector g) Recorders A pre column is

essential that increases the efficiency of chromatographic separation.

Ex; Guard columns

Glass columns are most commonly used because they can withstand higher temperature

Sampleunit,column&detector needs an oven to maintain higher temperature

Column length few centimetres to several hundred meters

Column used-packed columns

Capillary &open tubular

Analytical& preparative

Stainless steel columns are commonly used because they can withstand high pressure.

Only column unit needs an oven

Column length 25cm-100cm

Columns used-conventional columns

Micro bore columns

A. Bulk property:-

Refractive indexdectorsConductivity detectors

B. Solute property:-UV-visible detector

Fluorescence detectorsElectro chemical

detectors

A. Concentration dependent:- Thermal conductivity

detector Electron capture detector Argon ionization detector

B. Mass flow dependent Nitrogen phosphorous

detector Flame photometric

detectors

Detectors used are 2 types-