仪器分析化学(英语)PPT

spectral regions
transitions
X ray
K- and L-shell electrons
Far ultraviolet
Middle-shell electrons
Near ultraviolet
Valence electrons
Visible
Valence electrons
1. The Components of a Spectrometer
⑴ Light Source ⑵ Sample cell ⑶ Polychromator or Monochromator ⑷ Detector
2. Atomic spectrometry system
3. Dispersion
The science and art of determining the composition of materials with the instrumental methods based on a physical property characteristic of a particular element or compound
ICP
Eva.Temp. Exci. Temp.
high
low
mid
mid
low highest
highest high
stability
poor good good best
Application.
Qualitative Analysis Qualitative Analysis Quantitative Analysis Quantitative Analysis
2.1
The Nature of Radiant Energy
The Duality of Light:
1. Wave properties
Refraction Diffraction
Reflection Scattering
c
v cv
(2.1)
V frequency, C velocity of l_ig_ht , wavelength, v- wave number
How the method “works” Advantages and limitations of the method Illustrative instrumentation Applications Problems Bibliography
Chapter 2 Introduction to Optical Methods
3.1. Fundamentals of AES
Atomic Emission Processes
3.2. Instrumentation
1. Light source 3. Detector
2. Spectrometer 4. Readout
1. Light Source
Type
DC Arc AC Arc Spark
The Nature of Radiant Energy Spectral Regions Interaction of Radiation with Atom and Molecule Practical Sources of Radiation Spectrograph and Monochromator
2.3b Interaction of Radiation with Molecules
E(molecule) = Ee + Ev + Er E = E2 — E1 = hv
•Absorption •Fluorescence
M + hv →M* M + hv →M* →M + hv`
2.4 Instrumentation
⑴By a Prism
⑵By a Grating
Grating Equation
mnr sin sin
(2.3)
For a blazed reflection grating (echelette)
mnr 2 sin
(2.4)
Where: : blaze angle, : wavelength, : incident angle,
Chapter 1 Introduction
•Definition of Instrumental Analysis •Classification •Function •Important Considerations
1.1. The Definition of Instrumental Analysis
Light Source Progresses
2. Spectrometer
⑴Monochromater Optical-direct Read Spectrometor
⑵Polychromater Optical-direct Read Spectrometor
3. Detector
Where: w is diameter of the lens, f is the focal length.
4. A Typical Monochromator
Chapter 3
Atomic Emission Spectroscopy
3.1. Fundamentals of AES 3.2. Instrumentation 3.3. Analytical Methods of AES 3.4. Control of Analytical Interferences
Chemical Information observable Signal
by determination of physical properties
1.2. Physical Properties Useful in Instrumental Analysis
1. Interaction of Radiant Energy with Matter
UV-Vis. Spectrophotometry
IR Spectroscopy
2. Electrochemical Methods
Potentiometry
Polarography
Voltammetry
3. Chromatography
Gas Chromatography
Liquid Chromatography
i
(3.1) (3.2)
ni acb
(3.3)
⑵Lomakin Formula
I ACb
(3.4)
⑶Internal Standard Methods
R
Ix Is
Ax AsCsb
C
b x
KC
b x
(3.5)
⑷Standard Calibration Methods
Fig 3-16 Scheme of SCD Detector
3.3 Analytical Methods of AES
1. Qualitative Analysis ⑴Standard Iron Spectra Comparison ⑵Indicate Element Spectra Comparison ⑶Determination of Line Wavelength
1.4 Basic Function of Instrumentation
Signal Generators Input Transducers Signal Transformation Modules Output Transducers
1.5 Major Areas of an Instrumental Method
Dr
d
dx
cos
mnr f
(2.7)
Resolving Power
R
mNr
Blazing range
(m) (m 1)
m 0.5
The minimum position corresponds to an
optimum slit width
d opt
2 f
w
(2.8) (2.9) (2.10)
Near and mid infrared
Molecular vibrations
Far infrared
Molecular rotations
2.3a Interaction of Radiation with Atoms
▪ Emission
Atom (high excited state) → Atom (lower excited state) + h
⑴Spectrograph ⑵Photomultiplier Tube ⑶Segmented-array Charge-Coupled
Detector(SCD)
4. ICP-AES Instrumentation System
Two-dimensional array produced by the echelle mount
nr: number of grooves / mm, m: grating order
: diffracted angle,
Angle dispersion of a grating
ຫໍສະໝຸດ Baidu
d mnr
(2.5)
d cos
linear dispersion
dx mnr f
(2.6)
d cos
Reciprocal linear dispersion Dr
▪ Absorption
Atom (ground state) + h → Atom (high excited state)
▪ Fluorescence
Atom (ground state) + h → Atom (high excited state)
Atom (lower excited state) + hF
2. Quantitative Analysis
Quantitative Formula
⑴theoretical Formula of AES
I g e n ul Aul hvul
u 1 x Z 1 1 x
Eu kT
i
g
I A h v e n ul
ul
ul
x
E
u kT
ul Z 1 1 x
Instrumental Analysis
Shanghai University
Contents
▪ Introduction ▪ Introduction to Optical Methods ▪ Atomic Emission Spectroscopy
▪ Atomic Absorption Spectroscopy
2. Particular proper ( the Energy of a photon)
hc
E hv
hcv (2.2)
Where h is Planck’s constant,
h=6.6256×10-34 J.s
2.2
Spectral Regions
The most important spectral regions:
▪ The Absorption of Radiation: Ultraviolet and Visible ▪ Molecular Luminescence:Fluorometry and phosphorimetry ▪ The Absorption of Radiation: Infrared ▪ Introduction to Electrochemical Methods ▪ Potentiometry ▪ Polarography ▪ Introduction to Interphase Separations ▪ Gas Chromatography ▪ Liquid Chromatography
1.3.
Classification of Main Instrumental Methods
1. Optical Methods
Atomic:
Absorption Spectroscopy,
Emission, Spectroscopy
Fluorescence Spectroscopy
Molecular:
2. Electrical or Electrochemical Properties 3. Inter phase Separation 4. Other Properties
Mechanical Properties Thermal Properties Nuclear Properties Extensive Properties