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 x 10(-6) M and 2.0 x 10(-3) M. The biosensor reached 95% of the steady-state current in about 20 s and its sensitivity was 28.4 x 10(-3) microA x M(-1). The enzyme electrode retained 94% of its initial activity after 2 weeks of storage at 4 degrees C in 50 x 10(-3) M sodium phosphate buffer at pH 7.0.