Amperometric enzyme electrode for the determination of hydrogen peroxide based on sol-gel/hydrogel composite film

A new type of organic-inorganic composite material was prepared by sol-gel method, and a peroxidase biosensor was fabricated by simply dropping sor-ge l-peroxidase mixture onto glassy carbon electrode surface. The sol-gel comp osite film and enzyme membrane were characterized by Fourier-transform infr ared (FT-IR) spectroscopy and EQCM, the electrochemical behavior of the bio sensor was studied with potassium hexacyanoferrate(II) as a mediator, and t he effects of pH and operating potential were explored for optimum analytic al performance by using amperometric method. The response time of the biose nsor was about 10 s; the linear range was up to 3.4 mM with a detection lim it of 5 x 10(-7) M. The sensor also exhibited high sensitivity (15 mu A mM( -1)) and good long-term stability. In addition, the performance of the bios ensor was investigated using flow injection analysis (FIA), and the determi nation of hydrogen peroxide in real samples was discussed. (C)2000 Elsevier Science B.V. All rights reserved.