文档介绍：Chapter 4 Ultraviolet and Visible Spectrophotometry
. Concepts of UV-
. UV-Vis. Spectrophotometer
. Analytical Methods
. Concepts of UV-Vis. Spectrophotometry
1. Molecular absorption and Fluorescence
2. Lambert-Beer’s Law
(1)Transmittance T:
()
(2) Absorbance:
(3) Molar absorptivity
When: the unit of b is in cm , C in mol/L,
molar absorptivity is:
B:transition probability, : effective area of molecular
()
()
. UV-Vis. Spectrophotometer
AA Spectrophotometer
Double bean UV-Vis. Spectrophotometer
. Analytical Methods 1. Qualitative Analysis 2. Quantitative Analysis 3. Dual wavelength Spectrophotometry 4. Differential Spectrophotometry 5. Derivative Spectra
Qualitative Analysis ⑴pound
Chromophore
max(nm)
(mol--1)
Transition Type
R3 C—N —
200
3000
n→*
R3 C—S —
200
2000
n→*
—N=N —
340
10
n→*
—S —S —
250-330
1000
n→*
R2 C=S
5 0 0,2 4 0
10,9000
n→*
R2 C=O
2 8 0,1 9 0
20,2000
n→*, n→*
—COOR
205,165
50,4000
n→*,→*
⑵pound
Ion
n3d,e
max(nm)
Ion
n3d,e
max(nm)
Sc2+
0
------
Zn2+
10
------
Ti(H2O)63+
1
Cu+
10
------
VO2+
1
625
Cu(H2O)62+
9
592,794
Cr (H2O)63+
2
407,575
Ni(H2O)62+
8
395,650,740
V (H2O)62+
3
557
Co(H2O)62+
7
516,541,625
Cr (H2O)62+
3
709
Fe(H2O)63+
5
411,540,794
Mn (H2O)63+
4
476
Mn(H2O)62+
4
402,435,532