Kinetics of oxidation of hydrogen peroxide at hemin-modified electrodes in nonaqueous solvents

Hemin adsorbed on graphite electrodes and used to catalyse the reduction of hydrogen peroxide in an aqueous buffer and in a range of nonaqueous solvents has been described. The immobilised hemin is stable in the solvents examined. The rate limiting step involves the reaction between hemin and hydrogen peroxide. Kinetic analysis of the response in nonaqueous solvents showed that Imax / Kmapp increased linearly with the solvent hydrophobicity (log P) in all solvents, a trend that is explained by preferable partitioning of hydrogen peroxide into the polar hemin layer.