Incorporation of horseradish peroxidase in a kieselguhr membrane and the application to a mediator-free hydrogen peroxide sensor

Horseradish peroxidase was incorporated in a kieselguhr membrane. The elect ron-transfer process of the enzyme was examined by cyclic voltammetry. It w as observed that the electron-transfer reactivity of horseradish peroxidase was greatly enhanced, and that direct electrochemistry was accordingly fea sible. Using the merits of the direct electron-transfer reactivity of horse radish peroxidase and its specific enzymatic catalysis towards hydrogen per oxide, an unmediated hydrogen peroxide biosensor was constructed. The calib ration plot of this hydrogen peroxide sensor was linear in the range of 2.0 x 10(-6) mol/L -6.5 x 10(-4) mol/L. The relative standard deviation was 4. 1% for 6 successive determinations at a concentration of 1.0 x 10(-4) mol/L . The detection limit was 1.0 x 10(-6) mol/L.