A Prussian blue-based amperometric sensor for the determination of hydrogen peroxide residues in milk

A highly selective, sensitive, fast, and stable amperometric sensor for the determination of hydrogen peroxide residues in aseptic milk is presented. To fabricate this amperometric sensor, a thin film of Prussian blue was first electrodeposited on a glassy carbon electrode and then a Nafion polymer layer was formed on the top. It was found that Nafion film greatly improves the anti-interference ability and the stability of the Prussian blue-modified electrode. Factors that influence the overall analytical performance of the sensor, such as the concentration of Nafion drop and pH value of the electrolyte, were examined. Results show that the prepared sensor possesses efficient electrocatalytic activity towards hydrogen peroxide with the detection limit as low as 0.2 μM and linear range from 0.8 μM to 0.12 mM. The developed sensor was applied to the determination of hydrogen peroxide in milk with satisfactory results.