Amperometric hydrogen peroxide biosensor based on the immobilization of horseradish peroxidase by carbon-coated iron nanoparticles in combination with chitosan and cross-linking of glutaraldehyde

Magnetic carbon-coated iron nanoparticles were used to immobilize horseradish peroxidase on the surface of a polythionine modified glassy carbon electrode in combination with chitosan and cross-linking of glutaraldehyde. The electrochemical character of this enzyme electrode and its electrocatalytic reduction to H2O2 were studied by cyclic voltammetry. The effects of the common experimental variables were investigated. Under the optimum conditions, this method could be successfully used for the amperometric determination of H2O2 in a wide concentration range of 9.6 mu M to 3.16 mM with a detection limit of 3.6 mu M (S/N=3). Besides, the biosensor also exhibited good selectivity, stability and reproducibility.