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
c
Na
+
mmol/L 150
70
c
K
+
mmol/L 4
10
c
Cl
–
mmol/L 95
50
c
Ca
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 log (
)
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
Summary of Contents for FLEX ABL90
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Page 124: ...3 Wet section ABL90 FLEX reference manual 3 10 ...
Page 125: ...4 Electronics General information 4 2 Electronic boards and components 4 3 ...
Page 216: ...7 Performance characteristics ABL90 FLEX reference manual 7 30 ...
Page 263: ...9 Solutions General information 9 2 Solutions 9 3 Certificate of traceability 9 5 ...
Page 267: ...ABL90 FLEX reference manual 9 Solutions 9 5 Certificate of traceability ...
Page 268: ...9 Solutions ABL90 FLEX reference manual 9 6 ...
Page 269: ...10 1 10 Messages List of analyzer messages 10 2 ...
Page 310: ...10 Troubleshooting updated for software version 2 3 ABL90 FLEX reference manual 10 42 ...
Page 326: ...Appendix Quality control ABL90 FLEX reference manual I 16 ...
Page 327: ...II Appendix Traceability to the primary standards at Radiometer ...
Page 334: ...Appendix Traceability to the primary standards at Radiometer ABL90 FLEX reference manual II 8 ...