Insights into electrode-electrolyte adsorption dynamics via double potential step chronocoulometry and cyclic voltammetry
Ayesha Kousar, Tomi Laurila
Abstract
The crucial role of analyte adsorption in electrode reaction kinetics underscores the need for advanced methodologies to study the extent and nature of adsorbed molecules on electrode surfaces. In this study, we employed the classical yet underutilized technique of double potential step chronocoulometry (DPSC) to investigate the nature of adsorbed molecules on electrodes. We assessed the extent of adsorption of dopamine (DA) and the products of ascorbic acid (AA) and uric acid (UA) at increasing concentrations on carbon nanofiber (CNF) electrodes via DPSC measurements and compared the results with those obtained from the commonly used cyclic voltammetry (CV). DPSC findings indicated significant adsorption of component ions, specifically phosphate and chloride of phosphate buffer saline (PBS) electrolyte, on the electrode surface. The results presented in the manuscript demonstrate that DPSC can be a reliable technique for studying the specific adsorption in DA sensors, thus providing valuable insights for modifying materials to enhance DA sensor performance.