A novel hydrogen peroxide biosensor based on hemoglobin immobilized on magnetic chitosan microspheres modified electrode

A novel magnetic chitosan microsphere (MCMS) was prepared using carbon-coated iron magnetic nanoparticles and chitosan. Hemoglobin (Hb) was successfully immobilized on the surface of MCMS modified glassy carbon electrode (GCE) with the cross-linking of glutaraldehyde, and the immobilized Hb displayed an excellent electrocatalytic property to the reduction of H2O2 in the presence of the mediator of methylene blue (MB). The effects of the experimental variables such as the concentration of MB, solution pH and the working potential were investigated for optimum analytical performance using steady-state amperometry. This biosensor had a fast response of H2O2 less than 10 s and excellent linear relationships were obtained in the concentration range of 0.069-0.29 mM and 0.29-3.0 mM with the detection limit of 0.021 mM (S/N = 3) under the optimum conditions. Moreover, the selectivity, stability and reproducibility of this biosensor were evaluated with satisfactory results. (C) 2007 Elsevier B.V. All rights reserved.