Abstract: A new type of biosensor for detecting hydrogen peroxide in food residues was developed through modification of gold-palladium nano-alloys on the glassy carbon electrode. Due to large surface area, good biocompatibility and excellent catalytic properties of nano particles, the gold-palladium nano-alloy was used to immobilize horseradish peroxidase (HRP) on glassy carbon electrode. The electrochemical properties of electrode surface during each fabrication procedure were characterized by cyclic voltammetry and AC impedance method and the sensor performance of this sensor was evaluated by chronoamperometry. The results revealed that the hydrogen peroxide sensor had a good linear relationship in the range of 1× 10-7-5 × 10-3 mol/L for H2O2 and the limit of detection was 8.0×10-7 mol/L. It had better catalytic activity and good detection performance for detecting hydrogen peroxide. Moreover, this hydrogen peroxide sensor proved inexpensive, easy to use and strong repeatability, thus it is applicable for the hydrogen peroxide in food residues.

Key words: hydrogen peroxide sensor, gold-palladium nano-alloys, chronoamperometry, AC impedance