Potentiometric determination of hydrogen peroxide at MnO2-doped carbon paste electrode

A novel hydrogen peroxide (H₂O₂) potentiometric sensor, made with a MnO₂-doped carbon paste electrode (CPE), is reported. Under optimum conditions, the electrode gives a Nernstian response for H₂O₂ in the concentration range 3.00×10⁻⁷–3.63×10⁻⁴ mol/l, with a slope of 21–19.4 mV/pH₂O₂ and a detection limit of 1.2×10⁻⁷mol/l H₂O₂. In addition, this sensor offers some analytical characteristics such as sensitivity, good reproducibility and a simple preparation procedure. The effects of both the components of the electrode and other conditions on the potential response of the sensor, as well as the possible response mechanism, are discussed.