RADIOMETER ABL800 FLEX, Reference Manual

Page: 66 / 206

3. Optical measuring principles ABL800 FLEX Reference Manual
Optical system,
Continued
Determining
concentrations In the spectrum taken of a sample, the absorption recorded at each wavelength
contains contributions from each of the compounds in the sample. The task then is
to determine the magnitude of that contribution and thereby the concentration of
each compound in the sample.
The concentrations are determined using the following equation:
c A
n n
n
y y total
=1
128
K
=
∑
λ λ
where:
K
y
n
λ
= a constant specific to compound y at wavelength
λ
n
.
Matrix of
constants
The constants ( ) are determined using Multivariate Data Analysis
[
2
]
where
the spectra of the calibration compounds were considered together with the
reference values of the calibration compounds. The essential interfering substances
were also taken into account.
K
y
n
λ
3-6