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4. Specific Ion Calibration
4.1 Calibration Procedure
1.
Plug the Ion Selective Electrode into the
Sensor
socket.
If a separate Reference Electrode is being used, plus this into the separate
4mm Reference socket provided.
2.
Switch the meter on.
3.
Select and set up Ion mode, as detailed in section 3.
For the purposes of this handbook, the
WP-90
has been set up for 1.000ppM
as the Primary Standard and 0.100ppM as the Secondary Standard.
4.
Ensure that temperature has already been calibrated (see section 8.1).
NOTE
: A “
∗
” in place of the decimal point in the temperature readout
indicates that temperature is not calibrated.
5.
Rinse the Ion Selective, Reference and Temperature sensors in distilled water
and blot dry.
Primary Calibration
6.
Place the Ion Selective, Reference and Temperature sensors into the Primary
Standard.
Ensure that any Ionic Strength Adjusting Buffer (ISAB) that may be required
has been added (see the Ion Selective Electrode’s handbook).
A magnetic stirrer providing constant, gentle stirring generally improves
stability.
7.
Select Primary Calibration (
→
→
F1:Cal
→
→
F1:Ion Pri
).
The following message should be displayed. The current reading is displayed
on the top left. A “
∗
” in the reading indicates that the
WP-90
is currently not
calibrated.
1*234ppM 25.0
O
c
F1
:
Cal at1.000ppM
When the reading has stabilised, press
to perform a Primary
Calibration.
A “
∗
” will not be removed from the display after a 1-point Asymmetry
Calibration.