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Atomic Absorption SpectroscopyAtomic Absorption Spectroscopy（（ AAS)AAS)

APPLICATIONS

By:Tapeshwar Bhardwaj

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• IntroductionIntroduction• InstrumentationInstrumentation• ApplicationsApplications

Atomic Absorption Atomic Absorption SpectroscopySpectroscopy

（（ AASAAS ））

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What is AAS ?

Atomic Absorption Spectroscopy is a quantitative method of analysis that is applicable to many metals and a few elements.

Introductionntroduction

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What is AAS ?

Introduced in 1955

By Alan Walsh in Australia

First commercial AA Spectrometer was introduced in 1955.

Alan Walsh 1916-1998

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What is AAS ?

• An atomic absorption spectrophotometer consists of a l ight source, a sample compartment and a detector.

Light SourceLight Source DetectorDetector

SampleSampleCompartmentCompartment

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InstrumentationInstrumentation

Line source Monochromator Detector

Read-outNebulizer

Schematic diagram of a f lame spectrophotomer

Atomization

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Hollow Cathode Lamp Hollow Cathode Lamp (HCL)(HCL)

Cathode--- in the form of a cylinder, made of the element being studied in the f lameAnode---tungsten

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A hollow cathode lamp for Aluminum (Al)A hollow cathode lamp for Aluminum (Al)

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SpectrAA - AAS

MotorizedMirror

HCL

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Sample Atomization Techniques

Flame Atomization

Electro-Thermal Atomization/ Graphite Furnace

Hydride Atomization

Cold-Vapor Atomization

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Common fuels and oxidants used in flame spectroscopy

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Atomic Absorption Spectrophotometer

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Sensitivity and Detection l imit (ng/mL)

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APPLICATIONS

• ENVIRONMENTAL SCIENCE• FOOD TECHNOLOGY• • PHARMACEUTICALS• PETROCHEMICALS• • GEOCHEMICAL/MINING• • BIO-MONITORING• • AGRICULTURE• NANOMATERIALS• PATHOLOGY

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IN FORENSIC SCIENCES

1. Determination of trace elements

2. Elemental profiles of biological samples.

3. Trace elements in artificial fibres.

4. Determination of the mode of poisoning.

5. Hair analysis for heavy metal poisons.

6. Determinations of ammunition manufacturers.

7. Discrimination of objects/Elements.

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Advantages and disadvantages

High sensit ivity

[10 -10g (f lame), 10 -14g (non-f lame)]Good accuracy

(Relative error 0.1 ~ 0.5 % )High selectivity

Widely used

A resonance l ine source is required for each element to be determined

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