Ferrocene Branched Chitosan for the Construction of a Reagentless Amperometric Hydrogen Peroxide Biosensor

Chitosan was chemically branched with ferrocene moieties and further used as a support for the immobilization of horseradish peroxidase on a glassy carbon electrode. The reagentless biosensor device showed a linear amperometric response toward hydrogen peroxide concentrations between 35 × 10−6 M and 2.0 × 10−3 M. The biosensor reached 95% of the steady‐state current in about 20 s and its sensitivity was 28.4 × 10−3 µA · M−1. The enzyme electrode retained 94% of its initial activity after 2 weeks of storage at 4 °C in 50 × 10−3 M sodium phosphate buffer at pH 7.0.