Heavy Metal Ion Electrochemical Sensor Based On Ion Imprinted Polymer

With the rapid development of industry,the problem of water pollution has become increasingly serious.Among them,heavy metal pollutants have a serious threat to human health because of their strong toxicity and easy enrichment.Therefore,it is important to develop rapid,simple and sensitive methods to detect heavy metal ions in environment.Taking the advantages of low detection limits,low cost,ease of operation,and portable field detection,electrochemical methods play an important role in the detection of heavy metal ions Currently,the most popular method is to chemically modify the working electrode(such as glassy carbon electrode,carbon paste electrode,gold electrode,etc.)to improve the electrochemical sensor selectivity and stability in complex samples.In recent years,ion-imprinted polymers(?P)have been widely studied due to they are capable of selectively adsorbing heavy metal ions.Ion-imprinted polymers mainly include traditional ion-imprinted polymers(bulk-imprinted polymers)and surface-imprinted polymers.In this paper,to explore the effects of two types of imprinted polymers on sensor performance,three kinds of Cu(?)electrochemical sensors based on ion-imprinted polymer were constructed,and a series of tests were carried out on the performance of the sensor,including the following three parts:(1)An ion imprinting polymer(?P)electrochemical sensors based on chitosan-graphene oxide ion-imprinted polymer modified glassy carbon electrode(CS/GO-IIP)was developed by in-situ polymerization.And the composition and structure of the polymers were analyzed by FT-IR,SEM and EDS.The electrochemical performance was carried out by differential pulse anodic stripping voltammetry(DPASV).The results shown that the ion imprinted polymer modified electrode has higher peak current value of Cu(?)than the unmodified electrode,and has high selectivity and wide detection range(0.5 ?M?100 ?M)with a detection limit of 1.5 ?M;(2)Fe3O4 magnetic nanoparticles with uniform particle size were prepared by solvothermal method,then Fe3O4/SiO2 nanoparticles were prepared by sol-gel method.Finally,the surface Cu(?)ion imprinted polymer was prepared by using chitosan as functional monomer.The composition and structure of nanomaterials were analyzed by FT-IR,SEM,XRD and TGA.When using the surface Cu(?)ion imprinted polymer modified electrode to build the Cu(?)sensor,the shortcomings of the deep imprinting sites of the bulk ion-imprinted polymer were overcome and improves the utilization of imprinting sites.And the Cu(?)sensor exhibited the excellent detection signal,the anodic stripping peak current increased nearly four times compared with the non-imprinted material modified electrode.In addition,the sensor has the advantages of high selectivity and low detection limit with a detection limit of 5 nM.(3)Cu(?)surface ion-imprinted polymer materials(Fe3O4/PANI-Cu(?))were prepared by using aniline as monomer,and the composition and structure of Fe3O4/PANI-Cu(?)was analyzed by FT-IR,SEM,XRD and TGA.The electrochemical sensor constructed by Fe3O4/PANI-Cu(?),which exhibited excellent detection performance for Cu(?)in PBS buffer of pH=3.0.The anodic stripping peak current increased 4.2 times compared with the non-imprinted material modified electrode.In complex systems,the sensor still has good selectivity and low detection limit with a detection limit of 1.5 nM.