New Calibration Methods to Eliminate the Non-Ideal Effect of Drift and Hysteresis in All-Solid-State Potassium Electrode

The object of this study is to develop a non-ideal effects calibration method combining of hardware and software, and apply this calibration methods to an all-solid-state potassium electrode. In the hardware method, the calibration circuit owning drift and hysteresis calibration functions are developed to improve the accuracy of the measurement system. The experimental results show that both drift and hysteresis of all-solid-state potassium electrode can be reduced by a calibration circuit. In the software method, a three-time-constant model is used to simulate drift behaviors, and the drift of the all-solid-state potassium electrode is reduced by the software method. The measurement conditions of drift and hysteresis are set as below; the drift time is last for 12 h, the hysteresis loop is 10^-3 M → 10^-1 M → 10^-3 M → 10^-5 M → 10^-3 M KCl solutions, and the total loop time of hysteresis measurement is 5 min. Simulation of drift behaviors are in 10^-2 M and 10^-5 M KCl solutions. In addition, the alternated current (AC) impedance analyzer is used to measure the transfer impedance of the sensing membrane. The experimental results obtained by the AC impedance analyzer are used to explain the relationship between the hysteresis and transfer impedance of the sensing membrane.