25
24
CLEANING PROCEDURE
General
Soak in Hanna HI 7061 general clean-
ing solution for approximately 1 hour.
Removal of films, dirt or deposits on the membrane/
junction:
-
Protein
Soak in Hanna HI 7073 protein clean-
ing solution for 15 minutes.
-
Inorganic
Soak in Hanna HI 7074 inorganic clean-
ing solution for 15 minutes.
-
Oil/grease Rinse with Hanna HI 7077 or Oil & Fat
cleaning solution.
IMPORTANT: After performing any of the clean-
ing procedures rinse the electrode thoroughly
with a solution containing 2% ISA, refill (if
necessary) the reference chamber with fresh
electrolyte (HI 8093) and soak the electrode in
a solution very close to the next sample to
be measured for at least 1 hour before taking
measurements.
TROUBLESHOOTING
Evaluate the performance of your electrode 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:
refill with HI 8093 solution
• Dry Membrane/Junction: soak it overnight in
HI7081 (30.0 g/L NaCl) or HI7086 (23 g/L Na)
solution before use.
• Drifting: soak the electrode tip in warm HI 8093
solution for one hour. Refill with fresh HI 8093
electrolyte solution.
• Low Slope: refer to the Cleaning Procedure.
• No Slope: check the electrode for cracks in
glass stem or bulb and, if necessary, replace
the electrode.
• Slow Response/Excessive Drift: soak the tip
in HI 7061 solution for 30 minutes, rinse thor-
oughly in a solution with 2% of ISA, and then
follow the Cleaning Procedure.
The sensitive bulb should not touch the bottom of
the beaker.
The Hanna HI 76405 electrode
holder can be used for this
purpose.
During measurement, the
sample should be gently
stirred (approx. 100 rpm). The
Hanna HI 190M stirrer can be
used for this purpose.
STORAGE
When used frequently, the electrode should be stored
in a solution with a Na or NaCl concentration similar
to the sample to be measured. For longer periods of
storage, the electrode should be sored with a few
drops of appropriate solution in the protective cap.
For frequent use in different samples (1 or 2 times
per week), store the electrode in HI7081 (30.0 g/L
NaCl) solution if used for NaCl measurements with
HI 931100.
Store the electrode in HI 7080 (2.3 g/L Na) solution
if used for Na measurements with HI 931101.
For occasional use (once a month or less) store the
electrode dry and let it conditioning overnight in
HI7081 (30.0 g/L NaCl) or HI 7086 (23 g/L Na)
solution before use.
Note: NEVER STORE OR RINSE THE ELECTRODE
IN DISTILLED OR DEIONIZED WATER.
PERIODIC MAINTENANCE
Inspect electrode and cable. The cable used for
connection to the meter must be intact and there
must be no points of broken insulation on the cable
or cracks on the electrode stem or bulb. Connec-
tors must be perfectly clean and dry.
If any scratches or cracks are present, replace the
electrode.
Rinse off any salt deposits with water.
Refill the electrode with fresh electrolyte (HI 8093)
and let it stand upright for 1 hour.
Follow the Storage Procedure above.
MAGNETIC STIRRER
HI 190M
POWER
SPEED
ON
OFF
MAX
