Voltammetric ion selective electrode-based two-electrode ion sensing system for pH detection

A simple voltammetric two-electrode ion sensing system has been developed and utilized for pH value detection. In this system, active carbon (AC) electrode with constant electrode potential and good electrical conductivity is employed as the counter electrode. A solid contact voltammetric ion selective electrode (VISE), prepared by drop coating a layer of voltammetric ion selective membrane on a glassy carbon electrode, acts as the working electrode. Via cyclic voltammetry, the reduction peaks of the cyclic voltammograms are collected for quantification purposes. pH values have been detected by this system, using a voltammetric H+-selective working electrode. Furthermore, the results show a good linearity (r = 0.998) and precision (RSD = 1.05 %) which are comparable with those of conventional three-electrode system. This two-electrode system proposed here allows for quantification of pH values in complex samples (e.g. tap water and coffee solution). The detection results obtained here were in good agreement with the values detected by commercial glass pH meter.