1. ATOMIC ABSORPTION SPECTROMETER
SELİN CANSU ÖZTÜRK
ŞEYMA ATAKUL
SEZİN GÜNER

2. ATOMIC ABSORPTION SPECTROMETER
Introduction
Invention
Working Principle of AAS
Instrumentation
Interferences & Correlation Methods
Applications

3. INVENTION Introduced in 1955 by Alan Walsh in Australia
Firstly used for mining, medical treatment&agriculture
Alan Walsh( )

4. PROPERTIES OF AAS The most widely used method in analysis of elements
Based on the absorption of radiation
So sensitive (ppb)
Quantitative analysis

5. WORKING PRINCIPLE OF AAS
Electrons promote to higher orbitals for a short amount of time by absorbing a energy
M + hv → M*
Relises on Beer-Lambert Law
A= a.b.c

6. INSTRUMENTATION

7. LIGHT SOURCES Hollow Cathode Lamps Anot-Tungsten wire
Cathode made from the element of interest (Na,K,Ca..)
Argon or neon gas

8. LIGHT SOURCES Electrodeless Discharge Lamp
Typically argon gas at low pressure
Narrower line width
Not prefered

9. ATOMIZATION -Flame atomizer
Compounds making up the sample are broken into free atoms.
High temperature is necessary
Basic two types
-Flame atomizer
-Electrothermal atomizer

10. TYPES OF ATOMIZERS FLAME ATOMIZER Simplest atomization
Converts analyte into free atoms of vapor phase
Flammable &caustic gases
Not has an inert medium (−)
Short analysis time (−)

11. TYPES OF ATOMIZERS ELECTROTHERMAL ATOMIZER
A cylindirical graphite tube
Inert gas medium (Argon gas)
Longer anlaysis time than flame
Superior sensitivity, high accuracy

12. MONOCHROMATOR Also it is called wavelengh selector
Select the specific wavelenght
Polychromatic light →monochromatic light
Simple one is enough for AAS

13. DETECTOR Electromagnetic waves → electric current
The most used one Photomultiplier tube
Have fast response times

14. CALIBRATION TECHNIQUES
Two main techniques
Calibration curve method
Standart addition method

15. CALIBRATION TECHNIQUES
CALIBRATION CURVE METHOD
Draw a graph
Have two or more variables
-One is set at known values
-One is measured response
Most convenient for a large number of similar samples analysis.

16. CALIBRATION TECHNIQUES
An example of calibration curve method

17. CALIBRATION TECHNIQUES
STANDART ADDITION METHOD
To measure the analyte concentration in a complex matrix.
Most convenient for small number of samples analysis
Prevent effect of chemical & spectral interferences

18. INTERFERENCES Causes higher or lower absorbance value Two major groups
Chemical Interferences
Spectral Interferences

19. CHEMICAL INTERFERENCES
The most common one in flame atomizer.
Consequence of chemical reactions.
Reduce amount of oxygen in flame to overcome

20. SPECTRAL INTERFERENCES
Absorption or emission of the radiation at the same wavelength
Radiation which is absorbed→pozitive errors
Radiation which is emmitted→negative errors

21. SPECTRAL CORRELATION METHODS
TWO-LINE CORRELATION METHOD
Select two line
characteristic wavelength of analyte
very close to analyte line but not absorbed by analyte
Measure the difference between two lines

22. SPECTRAL CORRELATION METHODS
CONTINUUM SOURCE CORRELATION METHOD
Select two lamps
Deuterium lamp & hollow cathode lamp
When hollow cathode lamp is used total absorbace is measured
When deuterium lamp is used only background absorption is measured
Measure the difference between two lines.

23. SPECTRAL CORRELATION METHODS
ZEEMAN EFFECT CORRELATION METHOD
Presence of magnetic field.
Splitting of spectral lines.

24. -12
CONCLUSION
One of the most important technique in quantitative analysis
It is based on the absorption of radiation
Measurements could be done at ppb levels
It’s widely used method
The preparation of the sample is usually simple and rapid

25. CONCLUSION There are many adventages High sensitivity
[10-10 g (flame), g (non-flame)]
Good accuracy
(Relative error 0.1 ~ 0.5 % )
High selectivity

26. APPLICATIONS OF AAS
Water analysis (e.g. Ca, Mg, Fe, Si, Al, Ba content)
Food analysis
Analysis of animal feedstuffs (e.g. Mn, Fe, Cu, Cr, Se,Zn)
Analysis of soils
Clinical analysis (blood samples: whole blood, plasma,serum; Ca, Mg, Li, Na, K, Fe)

27. REFERENCES

28. THANKS FOR YOUR ATTENTION..