电沉积羧基化石墨烯-铋膜修饰玻碳电极电化学检测铅离子

Electrochemical detection of Pb^(2+) using electrodeposited carboxylated graphene-bismuth film modified with glassy carbon electrode

[目的]采用电沉积羧基化石墨烯(Carboxylated Graphene,CG)-铋(Bismuth,Bi)膜修饰的玻碳电极(Glassy Carbon Electrode,GCE)建立一种电化学检测铅离子的新方法。[方法]首先将裸GCE进行预处理,通过电沉积法将CG沉积于GCE上;然后将该电极浸入含铋离子和铅离子的溶液中,再将Bi膜沉积于电极表面,制成CG-Bi膜修饰的GCE;利用修饰好的GCE作为工作电极,实现对铅离子的检测。[结果]考察铋离子浓度、溶液pH值、沉积电位、沉积时间对铅离子检测的影响,并且获得这些影响因素的最适宜条件为铋离子浓度0.3mg·L^(-1)、溶液pH 4.5、沉积电位-1.2V、沉积时间350s。在最适宜的试验条件下,利用方波伏安法对不同浓度的铅离子进行测定,试验结果表明在0.075~0.500mg·L^(-1)的铅离子浓度范围内,峰电流值与铅离子浓度呈线性关系,检出限为0.002mg·L^(-1)。采用同一电极和不同电极对0.3mg·L^(-1)的铅离子进行测定,峰电流的相对标准偏差分别为10.39%和8.62%。同时考察了100倍浓度的氯化钠、氯化镁、氯化钾、氯化铝、硫酸铜、硝酸锌、乙酸镉和氯化钙对0.4mg·L^(-1)铅离子检测的影响,结果表明100倍浓度的氯化钠、氯化镁、氯化钾、氯化铝、硝酸锌和氯化钙对铅离子的测定影响较小,而100倍浓度的硫酸铜和乙酸镉对铅离子的测定影响较大;最后将该方法用于水样中铅离子的检测。[结论]这种新的电化学检测铅离子方法步骤简单、使用方便、检测快速、线性范围宽、选择性高,有望在食品检验、环境分析等领域实现应用。

[Objective]The present study was aimed to establish a new method for electrochemical detection of Pb^（2＋）using electrodeposited carboxylated graphene（CG）-bismuth（Bi）film modified by glassy carbon electrode（GCE）.[Methods]In first step,bare GCE was pretreated and electrodeposited with CG.Then,the CG modified GCE was immersed in the solution containing Bi 3＋and Pb^（2＋）.Bi film was further deposited on the electrode surface.The fabricated CG-Bi film modified GCE was used as working electrode for detecting Pb^（2＋）.The influences of Bi 3＋concentration,deposition voltage,deposition time,and pH of the solution on the Pb^（2＋）detection were investigated.[Results]Studies showed that the best combination of these factors were as following：Bi 3＋concentration at 0.3 mg·L^（-1）,deposition voltage at-1.2 V,deposition time for 350 s,and pH 4.5 of the solution.With the optimized factors,square wave voltammetry（SWV）was employed to test the different concentration of Pb^（2＋）.The results showed that electric current value（ECV）was increased with the increase of concentration of Pb^（2＋）,and ECV and the concentration of Pb^（2＋）were linear dependent within the range of[Pb^（2＋）]at 0.075~0.500 mg·L^（-1） with a detection limit at 0.002 mg·L^（-1）.Whenboth same and different electrodes were used at 0.3 mg·L^（-1） of[Pb^（2＋）],the relative standard deviation of peak electric current were 10.39% and 8.62%,respectively.The influence of 100 times higher concentration of NaCl,MgCl2,KCl,AlCl3,CuSO4,Zn（NO3）2,Cd（CH3 COO）2 or CaCl2 on the detection of Pb^（2＋）at 0.4 mg·L^（-1） were investigated.Results showed that effects of all selected materials except CuSO4 and Cd（CH3 COO）2,produced nonsignificant difference at 100 times higher concentration compared to control group on the determination of Pb^（2＋）.The method was further applied for the determination of Pb^（2＋）content in water.[Conclusion]The developed method possessed several benefits such as easy to be operated,convenient,fast response,broad response range,and high selectivity;therefore it is expected to be applied in the food protection and environmental analysis.