A study of the electrochemical oxidation of hydrogen peroxide on a platinum rotating disk electrode in the presence of calcium ions using Michaelis–Menten kinetics and binding isotherm analysis

The present work demonstrates a potential suppression in the electrochemical signal of H2O2 oxidation due to the presence of Ca2+ ions. A mechanistic scheme was proposed to include a reversible interaction of Ca2+ ions with either the electrode surface binding sites (competitive) or the complex sites (non-competitive). The degree of inhibition was inspected by evaluating the kinetic currents as a function of [Ca2+] applying Koutecky–Levich kinetics. These observations were further supported with models based on enzyme kinetics such as Michaelis–Menten model applying Lineweaver–Burk plot along with non-linear least-square fitting analysis. The experimental results suggests that the strength of the complex binding sites decreases considerably with increasing [Ca2+] and that a single H2O2 molecule is required to combine with one available active binding site.