A high-sensitive amperometric hydrogen peroxide biosensor based on the immobilization of hemoglobin on gold colloid/L-cysteine/gold colloid/nanoparticles Pt-chitosan composite film-modified platinum disk electrode

A hemoglobin (Hb)/gold colloid (nano-Au)/L-cysteine (L-cys)/nano-Au/nanoparticles Pt (nano-Pt)-chitosan (CHIT) composite film-modified platinum disk electrode (abbreviated to modified electrode) has been prepared to construct a biosensor for determination of H2O2. The electrochemical characteristics of the biosensor were studied by cyclic voltammetry and chronoamperometry. The modified process was characterized by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The morphologies of different composite film were investigated with scanning electron microscopy (SEM) and the element of composite film was investigated with X-ray photoelectron spectroscopy (XPS). Analytical parameters such as pH and temperature were also studied. The linear range for the determination of H2O2 is 1.4 x 10(-7) to 6.6 x 10(-3) mol/L with a detection limit of 4.5 x 10(-8) mol/L (S/N = 3). The sensor achieved 95% of the steady-state current within 10 s. The sensor exhibited high sensitivity (17.62 mu A/(mmol L)), selectivity and stability. The method is applied to the determination of H2O2 with satisfactory results. (C) 2007 Elsevier B.V. All rights reserved.