6 6
ELECTRODE CONDITIONING AND MAINTENANCE
Preparation
Remove the probe protective cap.
DO NOT BE ALARMED IF ANY SALT DEPOSITS ARE PRESENT.
This is normal with probes and they will disappear when rinsed
with water.
During transport tiny bubbles of air may have formed inside
the glass bulb. The probe cannot function properly under
these conditions. These bubbles can be removed by “shaking
down” the probe as you would do with a glass thermometer.
If the bulb and/or junction are dry, soak the probe in
HI 70300 Storage Solution for at least one hour.
If the probe does not respond to pH changes, electronics may
be down and the electrode should be replaced.
Test measurement
Rinse the probe tip with distilled water.
Immerse the probe in the Hanna pH buffer 7.01 (HI 7007)
until the solution is in contact with the metal ring and stirr
gently for 30 seconds. The reading must be near 7.01 pH.
Repeat the operation for pH 4.01 solution (HI 7004).
The difference from the previous reading must be near 3 pH
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
input lines in such way that the probe holder is kept filled with
sample.
When not in use, for longer time, dismount the probe and keep
in the protective cap with a few drops of HI 70300 Storage
Solution or, in its absence, HI 7082 (KCl 3.5 M Solution).
Follow the Preparation Procedure above before remount the probes.
Note:
Never store the probe in distilled or deionized water.
Periodic maintenance
Inspect the probe and the cable. The cable used for the con-
nection must be intact and there must be no points of broken
insulation on the cable or cracks on the probe stem or bulb.
