Amperometric sensor for hydrogen peroxide, based on Cu2O or CuO modified carbon paste electrodes

Carbon paste electrodes, modified by Cu₂O or CuO, were prepared and tested as sensors for hydrogen peroxide in aqueous solutions. They show a cathodic response to the analyte ranging from 0.45 to 0.14 mA/cm² for 1 mmol/L hydrogen peroxide for solutions of pH 5.2 and 7.3, respectively, at a working potential of –0.4 V vs. Ag/AgCl. The cathodic operation mode used diminishes or excludes the possibility of anodic discharge of contaminants usually present in biological fluids, and enables the use of the sensors in bioanalytical systems based on enzymes.