Determination of Concentrated Hydrogen Peroxide Free from Oxygen Interference at Stainless Steel Electrode

H₂O₂ is frequently used at high concentrations in various applications. It is very challenging to detect high concentrations of H₂O₂ and to eliminate oxygen interference for H₂O₂ detection through electrochemical reduction. In the present investigation, the electrochemistry of H₂O₂ at stainless steel electrode has been carried out for the first time. A cathodic peak for H₂O₂ reduction was observed at about -0.40 V, and no cathodic peak for dissolved oxygen reduction was observed on type 304 stainless steel electrode. Amperometric determination of H₂O₂ on type 304 stainless steel electrode displayed a linear range from 0.05 up to 733 mM with a detection limit of 0.02 mM (S/N = 3) and a sensitivity of 16.7 μA mM^-1 cm^-2. The type 304 stainless steel electrode not only shows much higher upper limit than other reported electrodes for the detection of concentrated H₂O₂ but also is free from oxygen interference, which is of great importance for practical applications. This method could detect H₂O₂ in wound wash and lake water with excellent recoveries. Moreover, we successfully applied the stainless steel electrode to determine glucose using glucose oxidase to catalyze the oxidation of glucose to generate hydrogen peroxide. The linear range for glucose is between 0.5 and 25 mM, which covers clinically important blood glucose concentrations well.