RADIOMETER FLEX ABL90, Справочное руководство

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5. Sensors and optical system ABL90 FLEX reference manual
5-44
Calibration of the optical system
The optical system is calibrated at two points using the following:
 The S7770 ctHb Calibration Solution with a known dye concentration to
determine the cuvette path length, l.
 A transparent solution from the solution pack in the analyzer to determine the
zero point,
I
o
.
The zero point, I
o
, is the current (or intensity) measured by the photodiode
array on the transparent solution in the cuvette. During this "blank calibration"
the ctHb is calibrated to this zero point.
I
o
is measured automatically during system start up and during calibrations.
The cuvette path length (i.e. the length of the light path) is determined from
Lambert-Beer’s Law by measuring the absorbance of the colored dye present in
the tHb Calibration Solution (S7770), which has a known equivalent hemoglobin
concentration.
Beer’s Law: A =
ε x
C
dye
x
l
where:
A = absorbance
ε
= extinction coefficient
C
dye
= concentration of colored dye
l = length of light path
It is recommended that a tHb calibration is performed every three months. See
section
tHb calibration in chapter 6: Calibration in the ABL90 FLEX operator's
manual for further information about the tHb calibration.
Calibration
materials
Zero point
Cuvette path
length
tHb calibration
frequency