Study on the Time-Dependent Slow Response of the Tin Oxide pH Electrode

It has been known that drift and hysteresis resulted from the slow response of the pH electrodes. These inherent drawbacks handicap the application of the pH electrodes. Thus, the time-dependent slow response of the tin oxide pH electrode was modeled by mathematical expression. In this study, the three time-constant model was utilized to fit the drift behavior of the tin oxide pH electrode. Besides combining with the three time-constant model and the concept of network analysis, the hysteresis model was derived. According to the experimental results, the modeled hysteresis width was close to the measured hysteresis width. The drift behavior and the hysteresis width of the tin oxide pH electrode were linked by the time-constant model. In other words, the hysteresis width can be predicted by the time-constant model of the drift behavior.