Current glass electrodes are resistant to the strongly acidic/basic aqueous condition. However, if the pH exceeds 12, some error may occur and the electrode response speed may become slower. Exercise the caution regarding the following item while performing the measurement.

  • Use glass electrode, the reference electrode (sleeve type or double-junction type) and  the temperature compensation electrode.
  • After the measurement, rinse the sensing part sufficiently with pure water.
  • When the pH is higher than 12, some error (alkaline error) may occur. To measure the pH value at this range, perform the two-point calibration with the standard solution of as high the pH as possible (saturated Ca(OH)2 solution (pH12.45 at 25℃)).

    *In this case of measuring a basic sample for the long term, the response speed of the glass electrode may become slower. In this case, immerse the sensing part in 1 mol/L HCl from 10 to 30 minutes, and then rinse it sufficiently with pure water.Measurement of strongly-acidic solutions up to 0.1 N HCl presents no particular problems.

We provide the following electrode for measuring the pH of strong alkali samples:
pH electrode for strong alkali samples (model: 9632-10D)
This product employs a new responsive membrane, which makes it more than 5 times as resistant to strong alkali samples as conventional products.
It can stably measure the pH of a strong alkali sample.