Faradaic and non-faradaic electrochemical impedance spectroscopy as transduction techniques for sensing applications

Abstract

Electrochemical Impedance Spectroscopy (EIS) stands out as a powerful technique for application in electroanalytical devices. Especially due to the possibility of label-free performance, use of miniaturized systems, in situ measurements and the relative low cost, impedimetric sensors have attracted particular attention in the recognition of analytes of medical, environmental and industrial interests. Depending on the presence or absence of redox species in the electrode or in the electrolyte, the technique can be categorized as faradaic or non-faradaic EIS respectively. The choice of the most suitable sensing method relies mainly on the expected application. Despite the nonfaradaic methods presents the advantages of the application in point-of-care devices due to the possibility of miniaturization of the electrodes and the absence of redox couple, the faradaic sensors tends to be more sensitive.