采用L-甲硫氨酸作为接枝基团对羧甲基壳聚糖进行接枝改性,然后与聚吡咯和多壁碳纳米管复合,制备改性羧甲基壳聚糖基导电复合材料,并构建了一种基于此导电复合材料修饰电极的用于同步测定Cd2+、Pb2+和Cu2+的电化学传感器。通过引入聚吡咯和碳纳米管以增强复合材料的导电性,同时碳纳米管的引入有利于提高复合材料的比表面积;此外,L-甲硫氨酸改性羧甲基壳聚糖引入了硫元素,提高了复合材料对重金属离子的螯合能力。在三种基材的协同作用下,实现了对Cd2+、Pb2+和Cu2+的同步测定。在最优的实验条件下,构建的电化学传感器对Cd2+、Pb2+和Cu2+的线性测定范围都为0.01～5μmol/L,检出限分别为5、4、6nmol/L。此外,该传感器具有较好的稳定性和选择性,以实际河水样品进行加标回收用于Cd2+、Pb2+和Cu2+的同步测定,三者的回收率在96.36%～103.35%之间,表明此传感器适用于实际水样中Cd2+、Pb2+和Cu2+的同步电化学分析监测。
In this paper,carboxymethyl chitosan was grafted with L-methionine,and then combined with polypyrrole and multi-walled carbon nanotubes to prepare a modified carboxymethyl chitosan-based conductive composite.An electrochemical sensor based on this conductive composite electrode was constructed for the simultaneous determination of cadmium,lead and copper ions.The electrical conductivity of the composite was enhanced by the introduction of polypyrrole and carbon nanotubes,and the introduction of carbon nanotubes was conducive to improving the specific surface area of the composite.In addition,L-methionine-modified carboxymethyl chitosan introduced sulfur,which improved the chelation ability of the composite to heavy metal ions.The simultaneous determination of Cd2+,Pb2+ and Cu2+ was realized under the synergistic action of three substrates.Under the optimal experimental conditions,the linear determination range of Cd2+,Pb2+ and Cu2+ by the constructed electrochemical sensor was 0.01～5μmol/L,and the detection limits were 5,4 and 6 nmol/L,respectively.In addition,the sensor had good stability and selectivity,and the actual river samples were recovered for the simultaneous determination of Cd2+,Pb2+ and Cu2+.The recovery rates of the three ions were between 96.36%～103.35%,indicating that the sensor was suitable for the simultaneous electrochemical analysis of Cd2+,Pb2+ and Cu2+ in actual water samples.
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基金资助
国家重点研发计划项目(2024YFD1600300);广东省基础与应用基础研究基金项目(2023A1515012465);湛江市科技计划项目(2022A01062);中国热带农业科学院国家热带农业科学中心科技创新团队项目(CATASCXTD202305);海南省自然科学基金项目(221QN0920)
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