Calibration For Ion-Selective Measurements - wtw inoLab Level 3 Operating Manual

Why calibrate?
When to calibrate?
ISECal
AutoRead
Display
TP Error
7.3

Calibration for ion-selective measurements

Ion-selective electrodes age and are temperature-
dependent. This changes the slope. Calibration determines
the current slope of the electrode and stores it in the
measuring system.
Thus, you should calibrate before each measurement and at
regular intervals.
Note
For calibration, use tempered standard solutions with a
temperature that differs by a max. of
temperature of the test sample.
l Before any concentration measurement if possible
l After connecting another electrode
l When the sensor symbol flashes after a voltage
disconnection, e.g. battery change
This is the conventional two-point or three-point calibration
procedure that uses 2 or 3 freely selectable standard
solutions. The concentration expected in the measurement
determines the concentration of the calibration standards to
be selected.
The calibration procedure automatically activates the
AutoRead function. In order to accept the current measured
value without waiting for the end of the AutoRead function,
g
simply press .
If you are using a temperature probe, any temperature
deviation ( 2 °C) of the standard solutions that is too large
±
is signaled by the display indicator, TP Error.
Ion concentration
2 °C from the
±
101