基于纳米金修饰的两种无汞型重金属微传感器的对比研究

Comparison of Mercury-free Microsensors Based on Gold Nanoparticles for Heavy Metals Detection

采用微加工技术制备了集成有工作电极和对电极的两种重金属微传感电极芯片,工作电极表面采用电沉积法修饰纳米金(Gold nanoparticles,GNPs),由半胱氨酸(L-cysteine,Cys)和天冬氨酸(L-aspartic acid,Asp)修饰制备Asp/Cys/GNPs/微传感电极芯片,并利用原位镀锡膜(Sn film)的方法,制成Sn/GNPs/微传感电极芯片。采用方波伏安法和方波溶出伏安法考察了两种微传感电极芯片对重金属离子Cu2+,Pb2+和Zn2+的响应特性。Asp/Cys/GNPs/微传感电极芯片可有效识别Cu2+和Pb2+,线性范围为5～2000μg/L,检出限为1μg/L;Sn/GNPs/微传感电极芯片可有效识别Cu2+,Pb2+和Zn2+,线性检测范围分别为5～500μg/L,5～500μg/L和10～500μg/L,检出限分别为2,3和5μg/L。相比而言,Asp/Cys/GNPs/微传感电极芯片具有较宽的检测范围,而Sn/AuNPs/微传感电极芯片具有较高的灵敏度,两种传感器绿色环保、制备简单、更新简便、易于集成,在水质在线监测方面具有应用前景。

This paper presents two kinds of mercury-free electrochemical microsensors for simultaneous detection of heavy metals,which are L-aspartic acid/L-cysteine/gold nanoparticles（Asp/Cys/GNPs/microelectrode chip） and Sn film/gold nanoparticles modified microelectrode chip（Sn/GNPs/microelectrode chip）.Electrochemical analysis of metal ions on Asp/Cys/GNPs/microelectrode chip was investigated by square wave voltammetry under the optimized conditions.The microsensor exhibited wide linear range from 5 μg/L to 2000 μg/L for Cu2＋ and Pb2＋ ions,with limit of detection of 1 μg/L.In situ tin film deposition was used in detection of heavy metals for the forming of alloy with heavy metals.Electrochemical analysis of metal ions on Sn/GNPs/microelectrode chip was investigated by square wave stripping voltammetry.The Sn/GNPs/microelectrode chip showed high sensitivity to Cu2＋,Pb2＋ and Zn2＋ ions.This microsensor revealed good linear behavior in the examined concentration ranges from 5 to 500 μg/L for Cu2＋ and Pb2＋,from 10 to 500 μg/L for Zn2＋,with a limit of detection of 2 μg/L for Cu2＋,3 μg/L for Pb2＋ and 5 μg/L for Zn2＋.In addition,metal ions detection method using the two kinds of microsensor are green,simple,reused and compatible with the microfluid chip for on-site analysis.