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 investigat ed as an amperometric detector for hydrogen peroxide in flow-injection analysis (FIA). At an operating potential of +0.48 V vs. Ag/AgCl cata lytic oxidation of the analyte is exploited for amperometric monitorin g. Experimental parameters, such as pH of the carrier working potentia l, flow rate and injection volume, are optimized. The amperometric sig nals are linearly proportional to the concentration of H2O2 in the ran ge from 0.005 to 10 mg/L, showing a detection limit (3 sigma) of 2.3 m u g/L. The method is applied to the determination of H2O2 in rain wate r and to a simple assay to quantify glucose in human plasma.