RADIOMETER ABL90 FLEX User Manual

5. Sensors and optical system ABL90 FLEX reference manual
5-20
Calibration of the pH and electrolyte sensors
The pH and electrolyte sensors are calibrated by determining the E
0
and
sensitivity from 2-point calibrations. Slight variations in sensor performance
between calibrations are addressed by performing a measurement of CAL 1
within every sample measurement process.
A 2-point calibration is performed at preset intervals using two solutions from
the solution pack. The precise values for these solutions are contained in the
smart chip located on the solution pack.
The pH and electrolyte values for CAL 1 and CAL 2 are as follows (approximate
values):
Level
Substance Unit CAL 1 CAL 2
pH - 7.3 6.8
cNa
+
mmol/L 150 70
cK
+
mmol/L 4 10
cCl
–
mmol/L 95 50
cCa
2+
mmol/L 0.5 2.3
The solution pH and electrolyte values are known and contained in the solution
pack smart chip.
The sensitivity is calculated in the following way and expressed as the
percentage of the theoretical sensitivity, calculated from the sensor signal of the
two calibration solutions (mV) and the nominal calibration values:
pH:
cal2 cal1
cal2 cal1
mV mV
S
61,5mV (pH pH )



Electrolyte sensors:
cal2 cal1
cal2
10
cal1
n(mV mV )
S
c
61,5mV lo
g
()
c



where n is the ionic charge.
Status is defined as the sensor signal of CAL 1 (rinse): mV1.
Introduction
2-point
calibration
Calibration
levels
Calibration

RADIOMETER ABL90 FLEX Specifications

General

Brand	RADIOMETER
Model	ABL90 FLEX
Category	Measuring Instruments
Language	English