Determination of hydrogen peroxide using a biosensor based on Fe3O4 magnetic nanoparticles and horseradish peroxidase with graphene-chitosan composite

A novel hydrogen peroxide (H2O2) biosensor was constructed based on Fe3O4 magnetic nanoparticles (MNPs) and horseradish peroxidase with graphene-chitosan composite material as a matrix. Fe3O4 MNPs were synthesised by chemical co-precipitation with sodium citrate as surfactant. Fourier transform infrared spectroscopy and transmission electron microscopy were applied for the characterisation of the obtained Fe3O4 MNPs. The conductivity of different composite films was researched by electrochemical impedance spectroscopy and the electrocatalytic properties of the H2O2 biosensor were studied by cyclic voltammetry. Under optimal conditions, experimental results indicated that the biosensor could electrocatalyse the reduction of H2O2; the reduction peak current had a good linear relationship with the concentration of H2O2 from 2.49 x 10(-5) to 1.67 x 10(-3) mol/l (R = 0.9990). The detection limit was 3.05 x 10(-6) mol/l (S/N = 3). This novel biosensor showed good sensitivity, stability and repeatability for H2O2 detection.