A functionalized chitosan derivative named sulfhydryl chitosan (CHS-NAC) was synthesised from chitosan (CHS) and N-acetyl-L-cysteine (NAC)

with 1-Hydroxybenzotriazole (HOBt) and 1-ethyl-3-(3-dimethylamino-propyl) carbodiimide hydrochloride (EDAC) as condensation agents.The structure of CHS-NAC was characterized by Fourier transform infrared spectroscopy (FTIR)

nuclear magnetic resonance (NMR) and X-ray diffraction (XRD).The content of thiol-group of CHS-NAC was measured to be 4.31110-4 mol/g through calibration curve taking use of Ellmans reagent.A layer of CHS-NAC film was modified onto the surface of glassy carbon electrodes by dispensing 8 L CHS-NAC solution.With the adhesive function of CHS-NAC modified film

gold nanoparticles and cytochrome c were modified onto the surface of glassy carbon electrode respectively.The electrochemical behaviors of these different modified electrodes were studied by cyclic voltammetry and electrochemical impedance spectra.The surface morphology of modified electrodes was characterized by scanning electron microscope (SEM).The influence of scan rate on the cytochrome c modified electrodes was also studied.Results showed that in low scan rate

electrochemical behavior was controlled by the surface process.The electrochemical catalytic analysis for hydrogen peroxide was carried out by using the cytochrome c modified electrode.Results showed that gold nanoparticles and cytochrome c can be fixed on the surface of glassy carbon electrode very well by CHS-NAC

and gold nanoparticles can effectively promote electron transfer of cytochrome c and the ability to electrochemically catalyze hydrogen peroxide.