Atomic Absorption Spectroscopy

# Atomic Absorption Spectroscopy

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## Atomic Absorption Spectroscopy

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1. Content 3.1. Theoretical Concepts 3.2. Atomic Absorption Instrumentation 3.3. Graphite Furnace Atomic Absorption 3.4. Control of Analytical Interferences | | 2

2. 3.1. Theoretical Concepts • The Atomic Absorption Process • Theoretical Concepts • Quantitative Analysis • Characteristic Concentration • Detection Limits | | 3

3. Fig3-2 Grotrian diagrams for K Fig 3-3Grotrian diagrams for Na | | 5

4. | | 6

5. 2. Theoretical Concepts⑴Integral Formula of AASFig 3-4 Typical Shape of A Atomic Absorption line | | 7

6. Integral Absorption FormulaBy atomic theory (3.1) By Line Shape Function ( the Nature distribute ) (3.2) The Peak Absorption Coefficient k0 is: (3.3) | | 8

7. ⑵ Peak Absorption Theoryby Lambert-Beer’s Law: (3.4) (3.5) (3.6) | | 9

8. The Absorbance is: (3.7) | | 10

9. When: va>> ve, and v0a= v0e, then kv≈k0, | | 11

10. (3.8) | | 12

11. (3.9) (3.10) | | 13

12. 3. Quantitative Analysis (3.10) | | 14

13. 4. Characteristic Concentration (3.11) | | 15

14. 5. Detection Limit (3.12) | | 16

15. | | 17

16. 1. Photometers for AAS | | 19

17. 1. Photometers for AAS | | 20

18. A New Type Photometer for AAS | | 21

19. 2. line source (Hollow Cathode Lamp ) Fig 3-13 | | 22

20. Hollow Cathode Lamp Emission Process Fig 3-14 | | 23

21. | | 25

22. | | 27

23. 4. Control of Analytical Interferences Ionization interference Matrix interference Chemical interference Background interference | | 28

24. Ionization Interference Ba → Ba+ + e- K → K+ + e- | | 29

25. Matrix Interference | | 30

26. Chemical Interference | | 31

27. The Method Of Standard Additions | | 32

28. | | 33

29. Background Interference | | 34

30. | | 35

31. (4.13) AHCL= Aa+ Ab (4.14) AD2=Ab, (4.15) Aa = AHCL- AD2 | | 36

32. 3.3. Graphite Furnace Atomic Absorption • Graphite furnace atomizer components • The Graphite Furnace Power Supply and Programmer • Quantitative analysis GFAAS • Effect of Matrix on Height and Area | | 37

33. 1. Graphite furnace atomizer components The Graphite Furnace Atomizer A basic graphite furnace atomizer is comprised of the following components: · graphite tube · electrical contacts · enclosed water cooled housing · inert purge gas controls | | 38

34. THGA graphite tube Fig 4-27 | | 39

35. The Graphite Furnace Power Supply and Programmer • A Graphite Furnace Temperature Program • Drying • Pyrolysis • Cool Down(optional) • Atomization • Clean Out • Cool Down | | 40

36. | | 41

37. | | 42

38. | | 43

39. | | 44