2.Molar absorptivityε
(1) Characteristic constant under certain condition for a
certain substance.
(2) Not change with c and wave path b. Under certain
temperature and wave length,εis only decided by the
c: concentration, g·L-１
a: absorptivity, L·g-１·cm-１
a andε: a =ε/ M （M : molar mass）
Transmittance: T
T : ratio of the radiant power transmitted to the incident radiant power :
ε = (6～10）× 104 : high sensitive；
ε = (2～6）× 104 : medium sensitive
ε < 2 × 104
: not sensitive。
Discrepancy of Lambert-beer’s law
The relationship between the absorbance and concentration may be nonlinear, which is the discrepancy of Lambert-Beer’s Law. The discrepancy may be caused by：
The selective absorbance and absorbance
curve
M + h → M*
