Amperometric NADH Biosensor Based on Magnetic Chitosan Microspheres/Poly(thionine) Modified Glassy Carbon Electrode

Novel magnetic chitosan-coated microspheres (MCMSs) were prepared by modifying carbon-coated iron magnetic nanoparticles with chitosan An amperometric dihydronicotinamide adenine dinucleotide (NADH) sensor was constructed based on immobilizing MCMS on the surface of a polythionine (m(-1)) modified glassy carbon elect ode (GCE) The fabrication of MCMS/IPTH film and its electrocatalytic effect on electrochemical oxiclation of NADH were investigated by electrochemical impedance spectroscopy (EIS) and voltammetric methods It was found that the result mg integrated films of PTH and MCMS exhibit high electrocatalytic response to NADH by significantly reduce its overpotential The effects of the experimental variables on the amperometric determination of NADH such as solution pH and working potential wee investigated for optimum analytical performance This electrochemical sensor had a fast response to NADH which was less than 10 s Linear response ranges of 2-10 mu M and 10-100 mu M and a detection limit of 0.51 mu M (S/N = 3) were obtained under the optimum conditions Moreover, the selectivity. stability and reproducibility of this biosensor was evaluated with satisfactory results