C hapter 2 Atomic Emission Spectroscopy

1. Chapter 2 Atomic Emission Spectroscopy

2. Chapter 2 Atomic Emission Spectroscopy 2.1. Introduction to Optical Methods 2.2. Fundamentals of AES 2.3. Instrumentation 2.4. Analytical Methods of AES 2.5. Control of Analytical Interferences

3. 2.1. Introduction to Optical Methods • The Nature of Radiant Energy • Spectral Regions • Interaction of Radiation with Atom • Instrumentation

4. 2.1.1 The Nature of Radiant Energy The Duality of Light: • Wave properties • Reflection • Scattering • Refraction • Diffraction (2.1) - V frequency, C velocity of light ,  wavelength, v wave number

5. 2. Particular proper ( the Energy of a photon) (2.2) Where his Planck’s constant, h=6.6256×10-34 J.s

6. 2.1.2 Spectral Regions

7. 2.1.3 Interaction of Radiation with Atoms • Emission Atom (high excited state) → Atom (lower excited state) + h • Absorption Atom (ground state) + h → Atom (high excited state) • Fluorescence Atom (ground state) + h → Atom (high excited state)  Atom (lower excited state) + hF

8. 2.1.4 Instrumentation ⑴ LightSource 1. The main components ⑵ Sample cell ⑶ Polychromator or Monochromator ⑷ Detector

9. 2. Atomic spectrometry system

10. 2.2. Fundamentals of AES 2.2.1. The Energy Level Structure of an Atom

11. 2.2. Fundamentals of AES Atomic Emission Processes ⑵ Emission ⑴ Excitation

13. Example 1.

14. Example 2.

15. 2.2.2 The Atomic Spectrum • ⑴ The wavelength of a line depends on the energy difference of two states ⑵The intensity of the line depends on the number of atoms at higher level

16. An atomic emission spectroscopic method need: • Enough high temperature environment to produce enough free atoms and there are enough atoms at higher excited states • A dispersion device to form a Spectrum • A detector to convert the radiant energy of every line to a analog electric signal • A output device to show the final results

17. 2.3. Instrumentation 1. Light source 2. Spectrometer 3. Detector 4. Readout

18. 2.3.1 Light Source

19. Inductively Coupled Plasma

21. ICP initial processes

24. Light Source Progresses

25. 2.3.2 Spectrometer ⑴Monochromatic Optical-direct Read Spectrometer ⑵Polychromatic Optical-direct Read Spectrometor

26. 1. Dispersion⑴Prism

27. (2) Grating

29. Dispersion Mechanism of Grating

30. Grating Equation (2.3) For a blazed reflection grating (echelette) (2.4) Where: : blaze angle, nr: number of grooves / mm, : wavelength, m: grating order : incident angle, : diffracted angle,

31. Angle Dispersion of a Grating (2.5) linear dispersion (2.6) Reciprocal linear dispersion Dr (2.7)

32. Resolving Power (2.8) Blazing range (2.9)

34. 2. A Typical Monochromator

38. Two-dimensional Array Produced by the echelle Mount

40. 3. Detector ⑴Spectrograph ⑵Photomultiplier Tube ⑶Segmented-array Charge-Coupled Detector(SCD)

41. ⑴Spectrograph ⑵Photomultiplier Tube

42. Multiply Phototube

43. ⑶Segmented-array Charge-Coupled Detector(SCD) Fig 3-16 Scheme of SCD Detector

47. ICP-AES Instrumentation System

50. 2.4 Analytical Methods of AES 1. Qualitative Analysis ⑴Standard Iron Spectra Comparison ⑵Indicate Element Spectra Comparison ⑶Determination of Line Wavelength