wtw inoLab 740, Operating Manual

Page: 112 / 274

Ion concentration
112
7.4 Measuring the ion concentration
Preparatory
activities
Perform the following preparatory activities when you want
to measure the concentration using ion-sensitive
electrodes:
Note
Incorrect calibration of ion-sensitive electrodes will result in
incorrect measured values. Calibrate regularly before
measuring.
Temperature probe The temperature measurement is absolutely essential for a
reproducible measurement. You can perform concentration
measurements using an NTC 30 or Pt1000 external
temperature probe using the integrated temperature probe
of another probe, or without a temperature probe. The
temperature probe that is used is indicated on the display by
v
,
y
, or
z
.
Note
The measuring system automatically recognizes the type of
the temperature probe used. If the measurement is made
without a temperature probe, proceed as follows:
1 Connect the electrode to the measuring module.
2 Adjust the temperature of the solutions, or measure
the temperature if the measurement is made without
a temperature probe.
3 Select the ISE measuring mode.
4 Calibrate or check the measuring system using the
ion-sensitive electrode.
1 Measure the current temperature of the test sample.
2 Adjust the temperature of the test sample and the
calibration standards to the same temperature
(maximum deviation: ± 2 °C).