Amperometric enzyme electrode for the determination of hydrogen peroxide based on sol–gel/hydrogel composite film Original Research Article

A new type of organic–inorganic composite material was prepared by sol–gel method, and a peroxidase biosensor was fabricated by simply dropping sol–gel–peroxidase mixture onto glassy carbon electrode surface. The sol–gel composite film and enzyme membrane were characterized by Fourier-transform infrared (FT-IR) spectroscopy and EQCM, the electrochemical behavior of the biosensor was studied with potassium hexacyanoferrate(II) as a mediator, and the effects of pH and operating potential were explored for optimum analytical performance by using amperometric method. The response time of the biosensor was about 10 s; the linear range was up to 3.4 mM with a detection limit of 5 × 10−7 M. The sensor also exhibited high sensitivity (15 μA mM−1) and good long-term stability. In addition, the performance of the biosensor was investigated using flow injection analysis (FIA), and the determination of hydrogen peroxide in real samples was discussed.