A comprehensive heterogeneous electron transfer rate constant evaluation of dissolved oxygen in DMSO at glassy carbon electrode measured by different electrochemical methods

• Generation of superoxide is the key step to study antioxidant activity through cyclic voltammetry.
• Heterogeneous electron transfer rate constant k0 value validates the generation of superoxide free radical.
• Evaluation of k0 through different methods, limitation and validation of each method.
• Electrochemical reaction mechanism of dissolved oxygen has been confirmed through digital simulation.

Molecular oxygen radicals are responsible for many problems like aging, cancer, lipid peroxidation, protein denaturation, oxidative stress etc., We present a comprehensive electrochemical investigation of the dissolved oxygen in DMSO containing 0.1 M TBAP as the supporting electrolyte. Different electrochemical techniques such as cyclic voltammetry, chronoamperometry and chronopotentiometry were used to extract heterogeneous kinetics and chemically coupled reaction kinetics related to the O2 radicals. The experimentally determined parameters obtained through different methods were further confirmed through digital simulation (DIGISIM). Heterogeneous electron transfer rate constant (k0) was determined by three different methods, Nicholson & Shain, Gileadi, and the Kochi methods. The calculated k0 values are different from the previously cited values.