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    石墨烯-Nafion/纳米金复合物修饰玻碳电极阳极溶出伏安法测定大米中痕量锌

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

    • 摘要: 制备了石墨烯(GP)-Nafion/纳米金(Au)复合膜修饰玻碳电极(GCE),并将其用于阳极溶出伏安测定大米中痕量锌。采用X射线衍射(XRD)、扫描电镜(SEM)、电化学交流阻抗谱(EIS)对修饰电极的结构和性能进行了表征。在pH 4.5的乙酸盐缓冲溶液中,-1.5 V(vs.SCE)富集150 s,以100 mV·s-1扫描速率从-1.3 V扫描至-0.6 V。锌在修饰电极上于-1.0 V处产生一灵敏的阳极溶出伏安峰,峰电流与锌的质量浓度在5.0×10-4~0.15 mg·L-1范围内呈线性关系,检出限(3σ)为2.8×10-4mg·L-1。方法用于测定大米样品中痕量锌的含量,并以此样品为基体做回收试验,测得回收率在98.0%~106%之间。方法的测定结果与石墨炉原子吸收光谱法测定值一致。

       

      Abstract: 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.

       

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