Addressing Non-Idealities and EIS Measurement: From Inspection to Implementation

Gold interdigitated electrode (IDE) structure is one of the commonly-used platforms for sensing. The response of IDE-based sensors is measured in different ways, of which non-faradaic electrochemical impedance spectroscopy (nf-EIS) is specially used to extract the analytes impedance characteristics without redox labels. Many research projects across various disciplines need students from different domains, such as Electrical Engineering, Chemistry, and/or Biology, to experience electrical measurements that can easily go wrong without notice. It is crucial to evaluate the intrinsic and extrinsic constraints that need to be resolved to get reliable and high-quality nf-EIS measurements, which are also reproducible in the presence of noise and other sources of error. This article provides examples and summarizes how to systematically address the effect of the commonly existing non-idealities to enable any student to get confidence in the interpretation and reliability of nf-EIS measurements they perform. As part of our experimental analysis demonstration, various conditions and volume optimization for adequate measurements are performed.