Extended Kalman Filtering for Estimation of Parasitic Artifacts in Three Electrode Electrochemical Sensors

In this article, we present an analysis of the parasitic artifacts in five working electrodes (WEs) of different metals in circular geometry using three terminal analysis proposed by Fletcher. The electrical parameters of the electrodes have been determined by extended Kalman filtering (EKF) using measured input-output responses. We have been able to extract the stray parasitic elements and establish their variations with relative positions. It has been found that the WEs closer to the counter electrode (CE) responds better with less parasitic effect. The impedance spectra of the network reveal that the measured response currents depends on the impedance of the three-terminal network not merely on the two terminal impedance between WE and CE. The parasitic leaking currents were compensated considerably by a using an external bridging capacitor.