葡聚糖还原石墨烯修饰玻碳电极检测水中痕量重金属镉

Detection of trace cadmium using glassy carbon modified with dextran reduced graphene

首先采用Hummer法制备氧化石墨,然后使用葡聚糖还原制备石墨烯,并修饰玻碳电极结合差分脉冲溶出伏安法建立了水中痕量重金属镉的检测方法。利用紫外分光光度计、红外吸收光谱、原子力显微镜及X射线光电子能谱等对所制备的石墨烯进行了表征分析,研究了其导电性和电化学性质。在pH值=6的醋酸钠-醋酸缓冲溶液中,Cd2＋在-0.87V产生灵敏的溶出峰,线性范围为0.5×10-9～1.20×10-7,检出限位0.15×10-9。采用无毒、环保的葡聚糖能够快速制备在水中分散性良好的石墨烯,且具有优异的电化学特性,能够实现痕量重金属镉的快速检测。

Graphene oxide prepared by the Hummers＇ method was reduced using dextran as a green reducing agent to produce graphene.Graphene-modified glassy carbon electrode combined with differential pulse stripping voltammetry was used for determination of trace cadmium ions in water.The prepared graphene was characterized and studied by UV spectrophotometry,Fourier transform infrared spectroscopy,atomic force microscopy and X-ray photoelectron spectroscopy,and its electrical conductivity and electrochemical properties were also studied with cyclic voltammetry and AC impedance spectroscopy.The results showed that dextran not only posses good reducing capacity which could successfully reduce graphene oxide to produce graphene with good conductivity,simultaneously,but can also be embedded into graphite inter-layers to increase the inter-layer spaces to promote better dispersion of graphene in aqueous solution.At pH=6acetic acid-sodium acetate buffer solution,Cd2＋ion exhibit a sensitive stripping peak at-0.87V,and the linear calibration curve ranged from0.5×10-6-1.20×10-7 with the detection limit of 0.15×10-9.By using the non-toxic,environmentally friendly dextran as the reducing agent,well dispersed graphene with excellent electrochemical characteristics can be quickly prepared,which was suitable for rapid detection of trace amounts of cadmium.