horiba LAQUAact-PD110, Instruction Manual, Page: 49 / 117

pH measurement
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Performing measurement
You can perform measurement in the measurement mode by immersing the pH
electrode in the sample. You can use the automatic hold function to judge the stability of
the measured value. The automatic hold function has two modes, the auto stability mode
and the auto hold mode. For the instruction to set the mode, refer to "Setting the auto
stability and auto hold function" (page 64).
1. Clean the pH electrode with pure water (or
deionized water) and wipe it with filter paper
or tissue paper.
2. 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 stable. Make sure to
keep the port open during calibration.
3. Immerse at least 3 cm from the tip of the pH
electrode in the sample solution.
In order for the internal solution to flow into the
sample solution, make sure to immerse the liquid
junction in the sample solution surely.
Stability judgment automatically starts and the pH
icon blinks until the measured value stabilizes.
When the measured value stabilizes, the pH icon
changes from the blinking state to the lit state
and the display is fixed to the stabilized
measured value.