Electrode Conditioning And Maintenance - Hanna Instruments HI 98240 Instruction Manual

ELECTRODE CONDITIONING
AND MAINTENANCE
Note: To prevent damage to the electrode, remove it from the sample
before turning the meter off.
With the meter OFF, detach the electrode from the instrument
and immerse it in the storage solution.
PREPARATION
Remove the protective cap.
DO NOT BE ALARMED IF SALT DEPOSITS ARE PRESENT.
This is normal with pH electrodes and they will disappear when rinsed
with water.
During transport tiny bubbles of air may form inside the glass bulb.
The electrode cannot function properly under these conditions. These
bubbles can be removed by "shaking down" the electrode as you
would do with a glass thermometer.
If the bulb and/or junction are dry, soak the electrode in HI 70300
storage solution for at least one hour.
For refillable electrodes
If the fill solution (electrolyte) is less than 1 cm (½") 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 (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 a few drops of the solution to be tested,
before taking measurements.
STORAGE
To minimize clogging and ensure a quick response time, the glass
bulb and the junction should be kept always moist and not allowed
to dry out.
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Put in the protective cap a few drops of HI 70300 storage solution or,
in its absence, filling solution (HI 7071 for single junction or HI 7082
for double junction electrodes). Follow the Preparation Procedure
above before taking measurements.
Note: NEVER STORE THE ELECTRODE IN DISTILLED WATER OR DRY.
PERIODIC MAINTENANCE
Inspect the electrode and the 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 with water.
For refillable electrodes
Refill it 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.
CLEANING PROCEDURE
General: soak in Hanna HI 7061 general cleaning solution
for approximately 1 hour.
Removal of films, dirt or deposits on the membrane/junction:
- Protein
soak in Hanna HI 7073 protein cleaning solution
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 taking any measurements.
TROUBLESHOOTING
Evaluate the performance of your electrode based on the following
possibilities:
• 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
electrodes, or HI 7082 for double junction electrodes.
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