Amperometric hydrogen peroxide biosensor based on covalent immobilization of horseradish peroxidase on ferrocene containing polymeric mediator

In this work, a new type of amperometric hydrogen peroxide biosensor was fabricated for the determination of H2O2. Horseradish peroxidase (HRP) was immobilized on a glassy carbon electrode by poly(glycidyl methacrylate-co-vinylferrocene) (poly(GMA-co-VFc)) film. A polymeric electron transfer mediator, containing copolymers of glycidyl methacrylate (GMA) and vinylferrocene (VFc) with different molar ratios, was prepared by free-radical copolymerization. The amperometric response was measured as a function of H2O2 concentration, at a fixed potential of +0.35 V vs. Ag/AgCl in phosphate-buffered saline (pH 7.0). The mediated hydrogen peroxide biosensor showed a fast response of less than 4 s of linear range 2.0–30.0 mM, with a detection of 2.6 μM. The sensitivity of the biosensor for H2O2 was 10.42 nA/mM cm2.