Flow injection analysis of hydrogen peroxide on copper-plated screen-printed carbon electrodes

Abstract

A disposable copper-plated screen-printed carbon electrode (CuSPE) was developed for the determination of hydrogen peroxide by flow injection analysis (FIA) at ambient temperature without deoxygenation. Cyclic voltammetry on the CuSPE in pH 7.4 phosphate buffer solution showed the growth of CuO and Cu₂O. A well-defined reduction signal corresponding to the mediation of CuO and Cu₂O occurred in the presence of hydrogen peroxide. The mechanistic study revealed that the reduction is a coupled-chemical reaction mechanism with the operation of pseudo-first order kinetics with respect to the concentration of Cu₂O. The calculated electrochemical rate constant (k_e) from Laviron’s model is 13.7 s⁻¹. Systematic investigations were made to optimize the experimental parameters for hydrogen peroxide detection by FIA. With a poised potential of −0.3 V versus Ag/AgCl and a flow rate of 2 ml min⁻¹, the calibration curve was found to be linear up to 200 μM hydrogen peroxide with a detection limit of 0.97 μM (S/N = 3). The CuSPE is fairly stable for repetitive measurements.