Measurement of Samples Including Solvents Other Than Water
Using a pH meter to measure samples including non-aqueous solvents is not as straightforward as measuring a sample with an aqueous solution. For this reason, note that the pH value measured in the non-aqueous solvent is only an indicator which shows the amount of hydrogen ion activity in the measuring solvent.
When performing a measurement, exercise caution regarding the following items:
- Use the glass electrode, the reference electrode (double-junction type) and the temperature compensation electrode.
- Because it takes a long time until the indication value becomes stable, it is advisable to read it approximately in 5 minutes.
- For a more accurate measurement, immerse the sensing part of the glass electrode in the sample all day and night before the measurement.
- After the measurement, immerse the sensing part of the glass electrode in 0.1 mol/L HCl for approximately 10 minutes and then rinse it thoroughly with pure water.
Also, rinse the inside of the external cylinder of the reference thoroughly with pure water.
- If the pH value is not within the range of pH 0 to pH 14, switch the display of the pH meter unit to mV display mode, and then perform the measurement.
Source by: Horiba