▎ 摘　　要

An electrochemical sensor based on tricobalt tetroxide nanoparticles-graphene nanocomposite film modified glassy carbon electrodes (GCEs) for sensitive determination of L-tyrosine (L-Tyr) was presented here. The nanoparticles were fabricated by electro-polymerization technology. Scanning electron microscopy was implemented to characterize morphology of the nanocomposite film. The electron transfer behavior of modified electrodes was investigated in 5 mM K-3 [Fe(CN)(6)]/K-4[Fe(CN)(6)] solution using cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The electrochemical response of modified electrodes toward L-Tyr was investigated by cyclic voltammetry (CV), square wave voltammetry (SWV), amperometry in detail. The results indicated that synergistic effect of Co3O4 NPs and graphene film dramatically improved the conductivity and sensitivity of the sensor. Under optimal conditions, a wide linear relationship between the responses and L-Tyr concentrations ranging from 1.0 x 10(-8) to 4.0 x 10(-5) mol L-1 was obtained with a comparatively low detection limit of 1.0 x 10(-9) mol L-1. Furthermore, the sensor also displays excellent sensitivity and high stability. To further study the practical applicability of the fabricated sensor, it was applied to detect real samples and the received results were satisfactory. (C) 2013 Elsevier B.V. All rights reserved.