19
ELECTRODE PREPARATION
PREPARATION PROCEDURE
Remove the electrode protective cap.
DO NOT BE ALARMED IF ANY SALT DEPOSITS ARE PRESENT. This is normal with electrodes and
they will disappear when rinsed with distilled/deionized water.
During transport tiny bubbles of air may have formed 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 is dry, soak the electrode in
HI 70300
Storage Solution for at least one hour.
ELECTRODE CALIBRATION PROCEDURE
It is recommended to calibrate the instrument frequently, especially if high accuracy is required.
The pH electrode should be recalibrated:
a) Whenever the pH electrode is replaced
b) At least once a week, but daily is advised
c) After testing aggressive chemicals and after electrode is cleaned
d) When high accuracy is required
e) If the pH calibration expired warning is displayed during measurement.
Every time you calibrate the instrument use fresh buffers and clean the electrode (see page 40).
PROCEDURE
A single one, two or three-point calibration can be performed, using the four predefined buffers
4.01, 7.01, 8.30 and 10.01 pH. For a single point calibration any of the three buffers may be
used, 8.30 pH is recommended.
Note
: The
HI 84531
will not accept other pH buffers for calibration.
• Pour small quantities of selected buffer solutions 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.
• Put a magnetic stir bar in the beaker that will be used for calibration.
• Remove the protective cap and rinse the electrode with some of the buffer solution to be used
for the first calibration point.
• Put the first beaker with calibration buffer in the beaker holder.
• Place the electrode holder on the top of the beaker and secure it by turning clockwise and press
STIR
.
