Determination of hydrogen peroxide with sensors based on heterogenous carbon materials modified with manganese dioxide

Abstract

Three different types of MnO2-modified electrodes were investigated on their electrochemical response towards hydrogen peroxide: a bulk-modified carbon paste electrode, a film-modified carbon paste electrode and a film-modified screen printed electrode. The sensors were characterized by voltammetric (cyclic voltammetry, linear sweep voltammetry) and amperometric methods (stationary and flow conditions). The best responses were obtained with a MnO2 film­modified screen printed carbon electrode which could be used as an electrochemical detector in flow injection analysis (FIA) using a NH3/NH4Cl buffer (0.2 M, pH 9.5) as a carrier. With FIA a detection limit (3σ) of 0.26 µg 1−1 could be achieved; the peak current was linear to the H2O2 concentration from 1 to 200.000 µg 1−1. The method could be successfully applied to the determination of H2O2 in various samples (cosmetic and medical products, rain water). With flow injection a sample frequency of 60 h−1 can be achieved.