62
Reducing pretreatment: immerse the electrode for a few
minutes in
HI7091
.
Oxidizing pretreatment: immerse the electrode for a few
minutes in
HI7092
.
If the pretreatment is not performed, the electrode will take
significantly longer to respond.
As with pH electrodes, gel-filled redox electrodes are more
suitable for industrial applications due to lesser maintenance
requirements. However, if working with refillable electrodes,
the electrolyte level should not fall more than 2½ cm (1”)
below the fill hole and topped up if necessary. Use
HI7071
refill solution for single junction and
HI7082
for double
junction electrodes.
In the event that measurements are performed with solu-
tions containing sulfides or proteins, the cleaning of the
diaphragm of the reference electrode must be performed
more often to maintain the proper functioning of the ORP
electrode. Therefore, immerse it into
HI7021
and measure
the response; the obtained value should be within 240
±
20 mV.
After this functional test, it is suggested to wash the electrode
thoroughly with water and proceed to the oxidizing or reduc-
ing pretreatment before taking measurements.
When not in use, the electrode tip should be kept moist and
far from any type of mechanical stress which might cause
damage. This can be achieved by installing the electrode
in such a way that it is constantly in a well filled with the
sample (stream or tank). When not in use, store the elec-
trode with
a few drops of HI70300
storage solution in
the protective cap.
Note
With industrial applications, it is always recommended to
keep at least one spare electrode handy. When anomalies
are not resolved with a simple maintenance, change the
electrode to see if the problem is alleviated.
pH
mV
pH
mV
pH
mV
pH
mV
pH
mV
0
990
1
920
2
860
3
800
4
740
5
680
6
640
7
580
8
520
9
460
10
400
11
340
12
280
13
220
14
160
