This document provides an introduction to atomic absorption spectroscopy. It discusses the basic principles, instrumentation, and applications of atomic absorption spectroscopy. The key points are: - Atomic absorption spectroscopy involves measuring the absorption of light by vaporized ground-state atoms of an element. - The basic components of an atomic absorption spectroscopy instrument are a radiation source, sample delivery system, monochromator, detector, and readout device. - Applications include determining metallic components in biological materials, isotopic analysis, and forensic analysis of samples like blood, soil, and gunshot residue.

1. AN INTRODUCTIONTO ATOMIC
ABSORPTIONSPECTROSCOPY
TEJASVI
BHATIA

2. CONTENTS:
Introduction
Definition
Principle
Instrumentation
Interferences
Generalapplications
Forensicapplications
References

3. INTRODUCTION
SPECTROSCOPY: It is branch of science
dealing with the study of interaction of
electromagnetic radiation with matter.
There are various spectroscopic techniques
and AAS is one of them .It is :
Discovered by Alan Walsh in 1955.
Quantitative method of analysis.
Microlitre volumes or micrograms masses
required.
Accurate and precise.

4. DEFINITION
Absorption of characteristic wavelength
light by the free atoms of a particular
element,when light of right wavelength
falls on it is called as Atomic absorption.
A method of spectrochemical analysis
based on the absorption of line radiation
by atomic species in the vapour phase is
called as Atomic absorption spectroscopy.

5. PRINCIPLE
Absorption of energy by ground
state atoms in gaseous state forms
the basis of AAS.
When light of particular wavelength
is allowed to pass through a flame
containing atoms of metallic
species part of light will be
absorbed.
Absorption is directly proportional
to density of atoms in flame.

6. INSTRUMENTATION

7. TYPESOFAAS
FAAS
GFAAS
AAS

8. BASICCOMPONENTSOFFAAS:
Radiation source
Sample delivery system
Monochromator
Detection system
Readout device

9. RADIATIONSOURCE
Radiation source must have the following
characteristics:
Monochromatic
Stable
Intense
Two types of radiation sources are used:
Hollow cathode lamp
Electrodeless discharge lamp

10. HOLLOWCATHODELAMP:

11. Electrodelessdischargelamp

12. SAMPLEDELIVERY
An introduction system for liquid
samples consists of three components:
NEBULISER
AN AEROSOL MODIFIER
FLAME OR ATOMISER

13. Nebulization
It is the method of formation of small
droplets from liquid sample.

14. ATOMISATION
It is the conversion of the sample
element into atomic vapors and the
device used for this purpose is called as
Atomizer. Flame atomizers are generally
used
Two types of burners are use
Total consumption burner
Premix burner

15. Undergraduate Instrumental Analysis, Robinson, p. 267.
TOTAL COMBUSTION BURNER

16. Premix (laminar flow) burner
 Sample, fuel, and oxidant mixed
prior to entering flame.
Instrumental Methods of Chemical Analysis, Ewing, p. 110.

17. MONOCHROMATORS
A device which selects radiations of a
particular wavelength.
TWO TYPES:
1.Prisms
2.Gratings

18. DETECTORS
A device which detects the signal after
coming out from sample.
Photomultiplier tube is most suitable
detector.

19. AMPLIFIER
Amplifies the signal that comes from the
detector
LOCK-IN amplifiers are used which
provide narrow frequency band and
produce good signal to noise ratio.
READOUT
CHART RECORDER are used which is
a potentiometer using a servometer to
move the recording pen.

20. INTERFERENCES
1. Chemical Interference: Formation of
stable or
refractory compounds.
2.Spectral Interference : there is
spectral overlap
3. Physical interference : It is due to
physical properties of sample.

21. GENERALAPPLICATIONS
Determination of metallic components
in biological materials
Isotopic analysis
Food industry
Determination of lead in petrol
Pharma industry
Steel and metal industry

22. FORENSICAPPLICATIONS
It is useful in quantitative analysis of:
Biological,medical and clinical samples
Environmental samples as soil samples.
Poisons or elements as copper, zinc in
food products.
Blood and serum analysis
Glass and ceramic industry
 Metals present in GSR.

23. REFERENCES
 Willard.H.Hobart(1986):Instrumental
methods of analysis;7th Edition,pp:224-259
 Pinta Maurice(1975):Atomic Absorption
Spectrometry
 Chatwal Gurdeep(1992):Instrumental
Methods Of Chemical Analysis;7th Edition,
pp:321-342
 G.Vidya Sagar (Vol. 2):Pharmaceutical
Analysis, pg:174-205
 elchem.kaist.ac.kr/vt/chem-
ed/spec/atomic/aa.htm