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For refillable electrodes**: Refill the electrode with fresh electrolyte (
HI 7071
for single
junction or
HI 7082
for double junction electrodes). Allow
the electrode to stand upright for 1 hour. Follow the Stor-
age Procedure above.
CLEANING PROCEDURE
General
Soak in Hanna
HI 7061
general cleaning
solution for approximately 30 minutes.
Removal of films, dirt or deposits on the membrane/junction:
Protein
Soak in Hanna
HI 7073
protein cleaning so-
lution for 15 minutes.
Inorganic
Soak in Hanna
HI 7074
inorganic cleaning
solution for 15 minutes.
Oil/grease
Rinse with Hanna
HI 7077
Oil & Fat cleaning
solution.
IMPORTANT
After performing any of the cleaning procedures rinse the
electrode thoroughly with distilled water, drain and refill the
reference chamber with fresh electrolyte, (not necessary for
gel-filled electrodes) and soak the electrode in
HI 70300
storage solution for at least 1 hour before reinstalling it.
TROUBLESHOOTING
Evaluate your electrode performance based on the following.
• Noise (Readings fluctuate up and down) could be due to:
- Clogged/Dirty Junction: refer to the Cleaning Procedure
above.
- Loss of shielding due to low electrolyte level (in refillable
electrodes only): refill with
HI 7071
for single junction
or
HI 7082
for double junction electrodes.
• Dry Membrane/Junction: soak in
HI 70300
storage solu-
tion for at least 1 hour. Check to make sure the installation
is such as to create a well for the electrode bulb to con-
stantly remain moist.
• Drifting: soak the electrode tip in warm
HI 7082
solution
for one hour and rinse tip with distilled water (refill with
fresh
HI 7071
for single junction electrodes and
HI 7082
for double junction electrodes if necessary).
• Low Slope: refer to the cleaning procedure above.
If the bulb and/or junction are dry, soak the electrode in
HI70300
storage solution for at least one hour.
For refillable electrodes**:
If the refill solution (electrolyte) is more than 2½ cm (1")
below the fill hole, add
HI 7082
3.5M KCl electrolyte solu-
tion for double junction or
HI 7071
3.5M KCl+AgCl
electrolyte solution for single junction electrodes.
For AmpHel
®
electrodes:
If the electrode does not respond to pH changes, the battery
is run down and the electrode should be replaced.
TEST MEASUREMENT
Rinse the electrode tip with distilled water.
Immerse the tip (bottom 4 cm / 1½") in the sample and stir
gently for approximately 30 seconds.
For a faster response and to avoid cross contamination of
the samples, rinse the electrode tip with the solution to be
tested, before taking your measurements.
STORAGE
To minimize clogging and assure a quick response time, the
glass bulb and the junction should be kept moist and not
allowed to dry out. 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, replace the solution in the protective cap
with a few drops of
HI 70300
storage solution or, in its
absence,
HI 7007
pH 7.01 buffer solution.
Follow the Preparation Procedure above before taking mea-
surements.
Note
NEVER STORE THE ELECTRODE IN DISTILLED OR DEION-
IZED WATER.
PERIODIC MAINTENANCE
Inspect the electrode and the cable. The cable used for the
connection to the controller must be intact and there must
be no points of broken insulation on the cable or cracks on
the electrode stem or bulb.
Connectors must be perfectly clean and dry. If any scratches
or cracks are present, replace the electrode. Rinse off any salt
deposits with water.
