ASV Determination of Trace Amount of Zinc in Rice with Graphene-Nafion/Nano-Au Modified Glass Carbon Electrode

A graphene, Nafion and gold nano-particles composite film modified glassy carbon electrode (GP-Nafion/Nano-Au/GCE) was prepared and its structure and property were characterized by XRD, SEM and EIS. In an acetate buffer solution of pH 4.5, Zn(Ⅱ) ion was accumulated at -1.5 V (vs.SCE) for 150 s and upon scanning from -1.3 V to -0.6 V at the rate of 100 mV·s-1, a sensitive anodic stripping voltammetric peak given by Zn2+ at the modified electrode at the potential of -1.0 V (vs.SCE) was observed. Linear relationship between values of peak current and mass concentration of Zn was obtained in the range of 5.0×10-4-0.15 mg·L-1, with detection limit (3σ) of 2.8×10-4mg·L-1. The method was used for the determination of Zn in rice sample, and using the same sample as matrix, recovery was tested by standard addition method, giving results of recovery in the range of 98.0%-106%. The analytical results found by this method were consistent with those obtained by GF-AAS.