Amperometric determination of hydrogen peroxide with a manganese dioxide film-modified screen printed carbon electrode

A carbon thick film electrode modified with an MnO2-film is investigated as an amperometric detector for hydrogen peroxide in flow-injection analysis (FIA). At an operating potential of +0.48 V vs. Ag/AgCl catalytic oxidation of the analyte is exploited for amperometric monitoring. Experimental parameters, such as pH of the carrier working potential, flow rate and injection volume, are optimized. The amperometric signals are linearly proportional to the concentration of H2O2 in the range from 0.005 to 10 mg/L, showing a detection limit (3 sigma) of 2.3 mu g/L. The method is applied to the determination of H2O2 in rain water and to a simple assay to quantify glucose in human plasma.