Use of an approach with a distribution of relaxation times for impedance analysis of a channel electrode in microfluidics.

Abstract

A DNA-functionalized electrochemical microelectrode is investigated through electrochemical impedance spectroscopy and modeled using an equivalent electrical circuit. Traditional parameter extraction methods rely on multiparameter regression, which can lead to ambiguous or nonphysical solutions. In this study, we propose an alternative approach based on the Distribution of Relaxation Times to analyze Electrochemical Impedance Spectroscopy data. This method allows us to identify characteristic electrochemical processes without assuming a predefined circuit topology or overfitting the data. By linking features of the relaxation-time distribution to physical properties of the system, such as charge-transfer resistance, double-layer capacitance, and surface coverage, we demonstrate improved robustness and interpretability in parameter extraction. This work establishes a foundation for label-free, miniaturized microfluidic biosensing applications with enhanced theoretical rigor and reproducibility.