Ametek IPS-4-UV, Руководство пользователя

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Overview | 1-1
OVERVIEW
This chapter discusses the features of the IPS-4 Analyzer and a summary
of how the entire system operates. This chapter also provides an overview
of the AMETEK electronics and sample system, and the various sub-sys-
tems that make up the entire analyzer system.
Principles of Operation
Basic Analytical Theory
The analyzer measures, over one or more bands of wavelength, the
absorbances of ultraviolet radiation (light) by a gas or liquid sample. The
concentrations of the components absorbing the light (absorbers) are then
determined from relationships developed through application of the ideal
gas law and the laws of Bouguer, Beer, and Lambert.
Thus, the absorbance, A , due to a single absorber is,
where l is the path length of the light in the fluid sample, [ x ] is the con-
centration (mole percent) of absorber x ,
k
 is the molar absorptivity of
absorber x at the measuring wavelength, T and P are the temperature
and pressure of the fluid sample, respectively, and R is the universal fluid
constant.
If more than one component is present, the total absorbance at a given
wavelength is the sum of the absorbances of the individual components.
In this case, absorbance measurements at additional wavelengths are re-
quired to develop a system of linear equations. If the number of measured
wavelengths is equal to or greater than the number of components be-
ing measured, absorbances of each component may be determined using
standard methods of linear algebra.
In practice, several wavelengths are used to calculate concentration [ x ].
Methods are implemented to correct for non-linearity.