User guide

ProLab 3000 Ion concentration
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ba75645e02 01/2010
9.4 Blank value correction
If the ion concentration in the sample is so small that it is not in the lin-
ear range of the electrode, you can increase the ion concentration in
the linear range with the blank value correction by the addition of a
blank value solution.
The displayed measured value is the difference between the actual
measured value and the determined blank value.
Calibration
Measuring
1 In the Measuring / ISE Setup menu, select and confirm the
menu item, Blank value correction.
The Blank value correction function is active (
✔).
2 Carry out a 2 to 5-point calibration according to the user guide
(see page 104).
As soon as a stable value is achieved for the standard calibra-
tion solution, the slope (mV) and evaluation (Error, +++) of the
electrode after calibration is displayed.
The infotext, Accept calibration and terminate is displayed.
3 Using [OK], confirm the infotext Accept calibration and termi-
nate.
The calibration record is displayed and output to the interface.
The calibration procedure is finished.
4 Close the calibration record with [OK].
The prompt for the measurement of the blank value appears.
5 Thoroughly rinse the electrode with deionized water.
6 Immerse the electrode in the blank value solution.
7 Start the measurement with [Continue].
The measured value is checked for stability (Stability control).
8 Wait for the measurement with stability control to end.
or
Take over the measured value with [OK].
The calibration record is displayed and output to the interface.
The calibration procedure is finished.
9 Close the calibration record with [OK].