Analysis of the Interaction of Radical Scavengers with ROS Electrogenerated from Hydrogen Peroxide

The polarographic (direct current, dc, and differential pulse, DP) and voltammetric oxidation of hydrogen peroxide on mercury electrodes has been examined. The electrooxidation of H2O2 involves hydroperoxide radical and superoxide anion radical able to interact with radical scavengers (antioxidants), namely 3-hydroxycoumarin, carvacrol, vanillin and gallic acid. For such interaction, theoretical equations are derived using the convective diffusion approximation and the steady-state conditions, as well as solving the differential equations of the Nernst diffusion-layer approximation by the method of dimensionless variables. The experimental results agree with the theoretical predictions and a kinetic parameter is proposed to evaluate the scavenging activity of antioxidants.