Electrochemical impedance spectroscopy (EIS) is used to evaluate the resistive state of an electrode surface. EIS is growing more popular in evaluating materials for biosensors and energy applications. In the case of biosensors, EIS can passively evaluate the binding event of a biomolecule to a surface recognition element. We have studied EIS inconsistent measurements from a bare carbon electrode under various conditions to evaluate the associated drift over multiple runs.[1] Without changing any variables run-to-run, a measurable drift can be expressed linearly or as a Langmuir isotherm over multiple measurements. The total change in charge transfer resistance is dependent on the solution and media, including the choice of surfactant used to solubilize various analytes.
Herein we will report our progress of EIS measurements from multiple different surfaces including peptides, polymers, and bare electrodes. We found that drift can be associated with specific surface changes (decoupling of surface modification or changes in surface states) and adsorbing of solution media to the surface. In the case of the bare electrode, surfactant and solution choice is important to minimize drift and increase confidence in run-to-run measurements.
Acknowledgements: The authors would like to acknowledge the financial support from NIH (P20 GM113131).
References:
[1] E. Ziino, S. Marnoto, J.M. Halpern, Investigation to Minimize Electrochemical Impedance Spectroscopy Drift, ECS Trans. 97 (2020) 737–745. https://doi.org/10.1149/09707.0737ecst.
