7 electrode test, Electrode test – Metrohm 781 pH/Ion Meter User Manual
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6.2 pH measurement (pH mode)
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6.2.7
Electrode test
PARAMETER pH
:
└
electrode test
├
electrode type
├
temperature
└
report
The pH/Ion Meter can carry out a pH electrode test, which permits the
quality of the electrode used to be evaluated. A detailed description of
the electrode test is given in Section 8.6.
electrode type: standard, gel, non-aq., own
Various types of pH electrodes have different evaluation criteria. For the
three most commonly used Metrohm pH electrode types the tolerances
are stored in the pH/Ion Meter: standard electrodes, gel electrodes and
non-aqueous electrodes.
electrode type: own
If you wish to define your own tolerances then select '
own
'. You
can now enter the limits for the quality features '
excellent
electrode
', '
good electrode
' and '
passing electrode
'.
An explanation of the individual limits is given in Section 8.6.3.
Regardless of the electrode evaluation, if '
own
' is selected as the
electrode type then you can also edit the limits for the offset po-
tential Uoff. This allows the electrode test to be carried out with
pH electrodes which, even with an Ag/AgCl reference electrode,
show a clearly shifted zero potential (e.g. antimony electrode).
The use of other reference electrodes can also result in changed
zero potentials.
temperature
0.0...25.0...99.9 °C
If no temperature sensor is connected then enter the temperature at
which the buffer will be measured here.
report:
OFF, short, full, line
After the electrode test you can automatically output the result in the
form of report. You can choose between the 'short' version containing
all the relevant data and the 'full' version, which also shows the measur-
ing curves as a graph. If you are only interested in the evaluation of the
electrode itself then select '
line
'. Only the result will be printed out, e.g.
'
excellent electrode
'. If no printer is connected then please select
'
OFF
'.
The report of the last pH electrode test can also be printed out later with