horiba LAQUAact D-74, Instruction Manual

Page: 40 / 112

pH measurement
24 HORIBA
• pH standard solution setting is CUST
This section describes the procedure for two-point calibration.
1. Press the key to enter the calibration mode and enter the standard solution
value for the 1st point calibration.
The current measured value is displayed on the sub screen.
2. Wash the pH electrode with pure water (or
deionized water) and wipe it with filter paper or
tissue paper.
3. Open the internal solution filler port of the pH
electrode.
If calibration is performed with the port closed, the
internal solution does not flow and the
measurement value is not stabilized. Make sure to
keep the port open during calibration.
4. Perform the 1st point calibration. Immerse at
least 3 cm from the tip of the pH electrode in
standard solution of the value entered in step
1.
In order to flow the internal solution into the
standard solution, immerse the liquid junction in
the standard solution surely.
key