heavy metals analysis

8/2/2019 Heavy Metals Analysis

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Envirotech Center for Research & Development

New Delhi

Harsh K. Dixit


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NAAQM Standards


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The Atomic Absorption Spectroscopy technique makes

use of absorption spectrometry to assess the

concentration of an analyte in the sample. Method is based on:

Active sampling using PM10 Respirable Dust Sampler

& then

Sample digestion

Analsis by Atomic absorption spectrophotometer


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PM10 Sampler

Hot plate

Analytical Balance

Digestion Chamber

Polypropylene bottle

GlasswaresAtomic absorption spectrophotometer


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Filter Paper: 8x10 EPM2000

Hydrochloric Acid (HCl) concentrated

Nitric Acid (HNO3) concentratedSulphuric Acid (H2SO4) concentrated

Metal Standard Solutions

Sodium borohydridePotassium iodide

Distilled water


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1. Microwave Digestion

2. Hot Plate Digestion


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Cut filter paper in small pieces

Place these small pieces into a beaker usingplastic forceps

Cover the filter with extraction solution

Place beaker on the hot plate for 30 min.

Dont allow sample to dry

Remove beaker from hot plate & allow tocool

Rinse beaker walls & wash with distilledwater

Filter the extract and make up to 50 ml.


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A light beam containing the corresponding

wavelength of the energy required to raise the

atoms of the analyte from the ground state to theexcited state is directed through the flame or

furnace. This wavelength is observed by a

monochromator and a detector that measure the

amount of light absorbed by the element, hencethe number of atoms in the ground state in the

flame or furnace. A hollow cathode lamp for the

element being determined provides a source of

that metals particular absorption wavelength.


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I. Flame atomic absorption: for Pb & Ni

II. Graphite furnace atomic absorption: forLow detection limit of Pb & Ni

III. Flame-VGA atomic absorption: for As


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Choose correct hollow cathod lamp

Align the instrument

Position the monochromator Select proper monochromator slit width

Set the light source current

Ignite the flame Regulate the flow of fuel & oxidant

Adjust the burner for maximum

absorption & stability


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Choose correct hollow cathod lamp

Place the furnace

Align the instrument Position the monochromator

Select proper monochromator slit width

Set the light source current

Switch on chiller

Regulate the flow of fuel & oxidant

Adjust the burner for maximum absorption &stability

Clean graphite tube with a firing


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C = (Ms Mb) x Vs x Fa/V x Ft

Where,C = concentration, g metal/m3Ms = metal concentration g/mLMb = blank concentration g/mL

Vs = total volume of extraction in mLFa = total area of exposed filter in cm2

V = Volume of air sampled in m3

Ft = Area of filter taken for digestion in cm2

heavy metals analysis

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