Techcomp UV 2600 - Chapter 2 Function; Work Principle

CHAPTER 2 FUNCTION
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CHAPTER 2 FUNCTION
2.1 Work Principle
UV2600 Spectrophotmeter is used for sample spectral analysis in UV and
visible area according to the law below:
A=KLC
A（Abs）is the absorbency of material tested to homogeneous light.
K is absorption coefficient of material tested; L is thickness of material tested;
C is concentration of material tested.
We can see from above law, A is proportional to C.
In actual test, homogeneous light attain photoelectricity conversion part such
as photodiode through sample and its light energy signal will be converted to
photocurrent. So A can be expressed by photocurrent. Assume that
photocurrent not through sample to be tested is I
0
，and photocurrent throught
sample to be tested is I
t
. So the ratio of the two is transmittance τ(T%).
τ=I
t
/I
0
×100％
A = －lgτ= －lg（I
t
/I
0
）= KLC
K has relation to wavelength of incidence homogeneous light and material to
be tested, i.e. different materials under different wavelengthes of
homogeneous light have different absorbency, which is theory basic for
qualitative and quantitative analysis.
Figure 2-1 Work Principle