Hanna Instruments HI 84430 User Manual

Page 10

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
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 clean the electrode (see the “pH Cleaning Procedure” section) and

use fresh buffers.

PROCEDURE

A single, two or three-points calibration can be performed, using the three predefined buffers

1.68, 4.01 and 8.30 pH. For a single point calibration any of the three buffers may be used,

but using 8.30 pH is recommended.

Note: The HI 84430 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 each beaker with the calibration buffer solution.
• Remove the protective cap, open the fill hole and rinse the electrodes 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.
• Insert the temperature probe into the dedicated tube guide.
• Immerse the pH electrode and the temperature probe approximately 2 cm (0.8”) into the

buffer paying attention not to touch the stir bar.

To select Electrode calibration screen follow the next steps:
• From pH meter screen press CAL function key then Electrode.
• From Titrator screen press CAL function key then Electrode.
• The electrode calibration screen will be displayed.
Point 1 calibration
• The 8.30 buffer will be selected by default. If necessary press the ARROW keys in order to

select a different buffer value.

• The (unstable measurement) symbol will be shown on the display until the reading becomes stable.

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 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.