1. Instrumental Analysis (CHM4001)
Text book
Principles of Instrumental Analysis, 6th Edition,
by Dougals A. Skoog and others

2. Analytical Chemistry (分析 化學)
Qualitative Analysis
Identify chemical signature
Supporting other fields
Quantitative Analysis
Clearly measure content (concentration)
Need to understand analytical instruments
Instrumentation
Develop new analytical instruments
Need Combined knowledge

3. Instrumental Analysis
Molecular Spectroscopy
IR, NIR, Raman, Ultra-Violet/Visible, NMR Fluorescence, Mass
Atomic Spectroscopy
Atomic Absorption, Atomic Emission
Separation
GC, HPLC, GPC, Electrophoresis
Electrochemical
Voltammetry, Potentiometry

6. Electromagnetic Radiation
Wave Property (Reflection, Scattering, Diffraction………)
Particle Property (Photon) (Emission, Absorption…)

7. Wave Parameters

8. Important Terminologies
Amplitude (A): Maximum length of electric vector
Period (P) : Time (second) required for the passage of successive maxima or minima.
Frequency () : Number of oscillation per second (1/P, Hz)
wavelength () : Linear distance between two equivalent points
Velocity of propagation: vi=i
in vacuum c =  = 3 ×108 m/s
Wavenumber (cm-1) : Reciprocal of wavelength in centimeters
Power (P) : energy of the beam reaches a given area per second

10. Electromagnetic Spectrum

12. Mathematical Descriptions of Wave
y: electric field, A: amplitude, t: time
 : phase angle,  : angular velocity (=2)

13. Superposition of Waves

14. Constructive Interference:
(1-2)= 0, 360, or n360
Destructive Interference:
(1-2)= 180, or 180 + n360

15. Same Amplitude, different frequency

16. Fourier Transform

17. Square Wave

18. Magnitude
Wavelength

19. Diffraction
Parallel beam is bent as it passes by a sharp barrier or through a narrow opening
Consequence of interference

20. Diffraction Grating and Monochromator

23. Ml = d sinθ

27. n

28. Coherent Radiation Two radiations must have identical frequency
Phase relationships must remain constant

29. Transmission of Radiation
Velocity of radiation is decreased when it passes a medium
The decrease depends on kinds and concentrations of atom, ion, molecules
No Frequency change
Refractive Index (RI)  (liquid:1.3~1.8, solid:1.3~2.5 or higher)

30. Transmission of Radiation
Periodic Polarization
Temporal deformation of electron cloud by alternating electromagnetic field
10-14 ~ second
No net energy change
Rate of propagation is slowed
Stepwise process involving polalization

31. Dispersion Variation of RI with wavelength or frequency Good for Prism
Good for Lens, window

32. Refraction Snell’s Law
Abrupt change in light direction from difference in velocity
Snell’s Law

33. Structure of Optical Fibers

35. Reflection
Abrupt change in light direction from difference in velocity
I0: intensity of incident beam, Ir : reflected intensity

36. Scattering
Rayleigh Scattering (elastic scattering) - scattering by molecules small than wavelength - proportional to 1/4, (polarizability of the particle)2
Scattering by Large Molecules: Tyndall Effect - determine the size and shape of polymer molecules and colloidal particles
Raman Scattering (inelastic scattering) - scattering with frequency change

37. Polarization

38. Quantum-Mechanical Properties
Photoelectric Effect
Photocathode - coated with alkali metals
h impinges on the surface - electrons are emitted with a range of kinetic energy
Large Voltage - produce a current in circuit
Decrease Voltage - small current
Stopping Voltage (Vo) - photocurrent = zero

39. E = h = eV0 + 
Work Function () : minimum work needed to eject electron from metal
Photocurrent is proportional to the intensity of radiation
Stopping voltage depends on the frequency of radiation
Stopping voltage depends on the chemical composition of the coating
Stopping voltage is independent of the intensity of incident radiation

40. Energy States of Chemical Species
Atoms, ions, and molecules can exists only in certain discrete states characterized by definite amounts of energy
When atoms, ions, and molecules absorb or emit radiation from one energy state to a second E1 – E0 = h = hc/
Electronic State
Vibrational State
Rotational State
Ground State
Excited State

42. Emission of radiation M + Energy  M*  M + h
Bombardment of electron beam  X-ray
Electrical current, flame, arc, furnance  UV, visible, IR
Beam of electromagnetic radiation  fluorescence
Exothermic chemical reaction  chemiluminescence

43. Line Spectra Band Spectra Continuum Spectra
Radiating from individual atomic particle that are well separated
Sharp spectral lines
Band Spectra
Gaseous radicals or small molecules
Not fully resolved
Bands from many quantized vibrational levels superimposed on the electronic energy level
Continuum Spectra
Radiation from heated solid: incandescence
Called black-body radiation
High temperature needs to emit UV region

47. Continuum Spectra

48. Absorption of Radiation
Atomic Absorption
Molecular Absorption
Absorption Induced by a magnetic field
E = Eelectronic + Evibrational + Erotational

49. Relaxation
Process

50. Quantitative Aspects of Spectrochemical Measurement
electrical signal (S)
radiant power (P)
S= k P
S= k P + kd
dark current (kd )
Signal without radiation

51. Transmittance (T)
Absorbance (A)

52. Beer’s Law a:(absorptivity, L g-1cm-1) b: thickness,
c: concentration(g/L)
molar absorptivity (L mol-1cm-1)