Measurement for sample including
fluoride ion

Fluoride ions corrode the glass. Therefore, the pH measurement with the glass electrode for a solution which includes fluoride ions is basically impossible. Although the useful life of the electrode may be shortened, however, the measurement with immersing the electrode in the sample for a given short time is possible. Also, if the sample is basic, the glass may relatively be capable of resisting the use because the fluoride ions become the complex.

<Measure Procedure>

Perform the measurement using the composite electrode or the integrated electrode in an exceedingly shortened immersion time. Because the sensing part is immersed every measurement operation, calibration shall be performed for each measurement. After the measurement, wash the electrode system with 0.1mol/L HCl, and then rinse it sufficiently with pure water.

*Note: The useful life of the electrode may become extremely shorter than the usual use.