Hanna Instruments HI 255 - Manual (Page 44)

44
For refillable electrodes:
If the filling solution (electrolyte) is more than 2½ cm (1”) below the fill hole,
add HI 7082 or HI 8082 3.5M KCl Electrolyte Solution for double junction or
HI 7071 or HI 8071 3.5M KCl+AgCl Electrolyte Solution for single junction
electrodes.
For 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 pH 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.
Take care that the sleeve holes of the EC probe are completly submerged. Tap
the probe repeatedly to remove air bubbles that may be trapped inside the
sleeve.
STORAGE PROCEDURE
To minimize clogging and assure a quick response time, the glass bulb and
the junction of pH electrode should be kept moist and not allowed to dry out.
Replace the solution in the protective cap with a few drops of HI 70300 or
HI 80300 Storage Solution or, in its absence, Filling Solution (HI 7071 or
HI 8071 for single junction and HI 7082 or HI 8082 for double junction
electrodes). Follow the Preparation Procedure on page 43 before taking
measurements.
Note: NEVER STORE THE ELECTRODE IN DISTILLED OR DEIONIZED WATER.
PERIODIC MAINTENANCE
Inspect the electrode and the cable. The cable used for connection to the
instrument 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.
pH Electrode Maintenance
For refillable electrodes:
Refill the reference chamber with fresh electrolyte (HI 7071 or HI 8071 for
single junction and HI 7082 or HI 8082 for double junction electrodes). Allow
the electrode to stand upright for 1 hour.
Follow the Storage Procedure above.