Deciphering the Platinized Surface Reactivity to Improve the Detection of Hydrogen Peroxide in Bioanalyses

Abstract

AbstractThe reactivity of platinized electrode surface (Pt‐black) towards the oxidation of hydrogen peroxide is analyzed in the most common physiological buffer, namely phosphate buffer saline, used in the development of biosensors. It is shown here that the oxidation of hydrogen peroxide by Pt‐black involves first the adsorption of phosphate anions, which facilitates the oxidation of hydrogen peroxide at lower potentials when compared to classic polycrystalline platinum. This gives insight in the excellent analytical features of platinized electrodes for the detection of H2O2, even at nanomolar concentrations. The reactivity of platinized electrodes can be further improved by an oxygen plasma treatment. We demonstrate herein that such treatment creates an outermost layer of PtO2 oxides on the deposit, which improves the oxidation of hydrogen peroxide thermodynamically and kinetically, as well as of hydroquinone and superoxide radical anion.