Potentiometric Determination of pH Values of Low Conductivity Solutions with the Glass Combination Electrode Equipped with Ionic Liquid Salt Bridge

By: Manabu SHIBATA

10 May 2013

It is difficult to measure accurately and quickly pH of low conductivity solutions by use of pH glass combination electrodes based on a KCl salt bridge (KClSB). The reasons are the variation of the liquid junction potential (LJP) between a KClSB and a sample solution, and the change of pH in the sample solution due to the leakage of the concentrated KCl from the liquid junction. In order to solve the intrinsic problems, a new reference electrode, where an ionic liquid was used as the material of liquid junction, has proposed. The pH glass combination electrode equipped with an ionic liquid salt bridge (PUREIL electrode) enables us to measure accurately and quickly pH of less than 10 mS m-1 sample solutions such as pure water and boiler water. In this paper, we show the pH measurement of 10 mS m-1 sulfuric acid solution by use of PUREIL electrode.

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