Amperometric Biosensor for Hydrogen Peroxide Based on Sol-Gel/Hydrogel Composite Thin Film

Abstract

A reagentless amperometric hydrogen peroxide biosensor was developed. Horseradish peroxidase (HRP) was immobilized in a novel sol-gel organic-inorganic hybrid matrix that is composed of silica sol and a grafting copolymer of poly(vinyl alcohol) with 4-vinylpyridine (PVA-g-PVP). Tetrathiafulvalene (TTF) was employed as a mediator and could lower the operating potential to −50 mV (versus Ag/AgCl). The sensor achieved 95 % of the steady-state current in 15 s. Linear calibration for hydrogen peroxide was up to 1.3 mM with the detection limit of 2.5×10−7 M. The enzyme electrode retained about 94 % of its initial activity after 30 days of storage in a dry state at 4 °C.