12
For refillable electrodes:
If the fill solution (electrolyte) is more than 2½ cm (1") below the fill
hole, add
HI 7082
3.5M KCl electrolyte solution for double junction or
HI 7071
3.5M KCl+AgCl electrolyte solution for single junction
electrodes.
For a faster response, unscrew the fill hole screw during measurements.
For AmpHel
®
electrodes:
If the electrode does not respond to pH changes, the battery is run
down and the electrode should be replaced.
MEASUREMENT
Rinse the electrode tip with distilled water. Immerse the tip (bottom
4 cm /1½") in the sample and stir gently for a few seconds.
For a faster response and to avoid cross contamination of the samples,
rinse the electrode tip with a few drops of the solution to be tested,
before taking 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.
Replace the protective cap with a few drops of
HI 70300
storage
solution or, in its absence, electrolyte solution (
HI 7071
for single
junction, or
HI 7082
for double junction electrodes). Follow the
Preparation Procedure above before taking measurements.
NEVER STORE 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.
Connectors must be perfectly clean and dry. If any scratches or cracks
are present, replace the electrode. Rinse off any salt deposits.
For refillable electrodes:
Refill the reference chamber 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 Storage Procedure above.
13
CLEANING PROCEDURE
General
Soak in
HI 7061
general cleaning solution for
approximately 30 minutes.
Removal of films, dirt or deposits on the membrane/junction:
-
Protein
Soak in
HI 7073
protein cleaning solution for 15 min.
-
Inorganic
Soak in
HI 7074
inorganic cleaning solution for
15 minutes.
-
Oil/grease
Rinse with
HI 7077
Oil & Fat cleaning solution.
IMPORTANT:
After performing any of the cleaning procedures rinse
the electrode thoroughly with distilled water, 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 taking measurements.
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 fresh
HI 7071
for single junction or
HI 7082
for double junction electrodes.
•
Dry Membrane/Junction:
soak in
HI 70300
storage solution
for
at least 1 hour.
•
Drifting:
soak the electrode tip in warm (approx. 50-60°C)
Hanna
HI 7082
solution for one hour and rinse the tip with
distilled water. Refill with fresh
HI 7071
for single junction
electrodes and
HI 7082
for double junction electrodes (refillable
electrodes only).
•
Low Slope:
refer to the cleaning procedure above.
•
No Slope:
check the electrode for cracks in glass stem or bulb
and replace the electrode.
•
Slow Response/Excessive Drift:
soak the tip in
HI 7061
solution for 30 minutes, rinse thoroughly in distilled water and
then follow the Cleaning Procedure above.
