9
It is recommended to calibrate the instrument frequently, especially if
high accuracy is required.
The pH range should be recalibrated:
• Whenever the pH electrode or temperature probe is replaced.
• At least once a week.
• After testing aggressive chemicals.
• When extreme accuracy is required.
PREPARATION
Pour a small quantity of buffer solution into clean beakers. For
accurate calibration use two beakers for each buffer solution, the first
one for rinsing the electrode and the second one for calibration.
PROCEDURE
In order to perform pH calibration:
• Make sure that the meter is in the pH mode (HI 9125 only).
• Remove the protective cap and rinse the electrode with some of
the buffer solution to be used for the first calibration point.
There is a choice of 5 memorized buffers: 4.01, 6.86, 7.01, 9.18 and
10.01 pH.
TWO-POINT CALIBRATION
• Press the CAL key. The "CAL" and " " indicators will be
displayed. The secondary LCD will display buffer "7.01". If a
different calibration buffer is desired (e.g. “6.86”), use the UP
and DOWN arrow keys to change the displayed value.
• Submerge the electrode approx. 4 cm (1½") into the solution,
place the temperature probe as close as possible to the electrode
and stir gently.
pp
pp
p
H CALIBRATIONH CALIBRATION
H CALIBRATIONH CALIBRATION
H CALIBRATION
or
20
For refillable electrodes, if the refill solution (electrolyte) is more than 2½
cm (1") below the fill hole, add the appropriate Electrolyte Solution.
MEASUREMENT
Rinse the electrode tip with distilled water, immerse it 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 the solution to be tested, before taking
any measurements.
STORAGE PROCEDURE
To minimize clogging and ensure a quick response time, the glass
bulb and the junction should always be kept moist.
When not in use, store it with a few drops of HI 70300 storage
solution in the protective cap.
NEVER STORE THE ELECTRODE IN DISTILLED OR DEIONIZED
WATER.
PERIODIC MAINTENANCE
Inspect electrode and cable. The cable must be intact. No cracks
should be seen on the electrode stem or bulb. If any scratches or cracks
are present, replace the electrode. Rinse off any salt deposits with water.
Connectors must be perfectly clean and dry.
For refillable electrodes:For refillable electrodes:
For refillable electrodes:For refillable electrodes:
For refillable electrodes:
Refill the electrode with fresh electrolyte (see the electrode’s specifications
to select the correct refilling solution). 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 ½ hour.
•
Protein
Soak in Hanna HI 7073 Protein Cleaning
Solution for 15 min.
•
Inorganic
Soak in Hanna HI 7074 Inorganic
CleaningSolution for 15 min.
•
Oil/grease
Rinse with Hanna HI 7077 Oil & Fat Cleaning
Solution for 1 min.
IMPORTANT: After performing any of the cleaning procedures, rinse
the electrode thoroughly with distilled water and soak it in HI 70300
Storage Solution for at least 1 hour before taking measurements.