Applications Of Thin-film And Molecular Imprinted Electrochemical Sensors For Detecting Several Environmental Monitoring Objects

In daily production and life,many necessities of life and industrial raw materials were discharged to the environment in the process of use inevitably,which have a direct or potential harm to the environment.Thus,they become the object of environmental monitoring.As industrial raw materials and synthetic intermediates,hydroquinone(HQ),catechol(CC)and resorcinol(RC)are widely used in pesticides,chemicals,dyes and medicines.The dihydroxybenzene isomers widely exist in the ecological envirinment and are difficult to degrade,which may threaten human health,so they are treated as an important environmental pollutant.Sulfamethoxazole(SMZ)is one of the most frequently using in the sulfonamides antibiotics,which are widely used in both medicine and veterinary practice because of its broad-spectrum activity,low cost,and effectiveness as growth promoter.However,it may cause severe potential harm to human and ecological environment due to discharge into the environment through a variety of ways.Therefore,to find a simple,fast way to detect HQ,CC,RC mixture and SMZ is the key to solve the environmental monitoring problems.This article prepared poly(p-aminobenzene sulfonic acid)modified electrode and applied to detect HQ,CC,RC mixture.Using o-aminophenol as imprinted molecule,a molecularly imprinted sensor for specific recognition to sulfamethoxazole was prepared by molecularly imprinting technique.The main research work of this paper is as follows:(1)Poly(p-aminobenzene sulfonic acid)modified graphite electrode(PABSA/GE)was prepared by electropolymerization,and the preparation conditions were optimized.The electrochemical behavior of dihydroxybenzene isomers on PABSA/GE was studied by different pulse voltammetry(DPV)and cyclic voltammetry(CV).The results indicate that the modified electrode exhibited good eleetrocatalytic response and separation function.The oxidation peak potential of HQ,CC and RC are located at 0.100V,0.200V and 0.610V,respectively.The linear range of HQ and RC are 1.00×10-6～6.00×10-4 mol/L,the linear range of CC is 5.00×10-6～6.00×10-4 mol/L.The method was successfully applied for single HQ,CC,RC or their mixture determination in industrial waste water.The electropolymerization mechanism of p-aminobenzene sulfonic acid was studied.The electrocatalysis mechanism of HQ,CC and RC on PABSA/GE was also studied by electrochemical and photochemical methods.(2)A molecular imprinted film of sulfamethoxazole with selectivity has been prepared using o-aminophenol as functional monomer,sulfamethoxazole as template molecule.The basic characteristics of the sensor were characterized by cyclic voltammetry and electrochemical impedance spectroscopy.The imprinting efficiency is 35.4%,the numbers of sulfamethoxazole and o-aminophenol of binding sites is 6.The interaction of o-aminophenol and sulfamethoxazole was studied by spectrophotometric.The catalytic mechanism of electrochemical oxidation of sulfamethoxazole on modified electrode was studied.(3)The experiment found that the sensor had high catalytic activity for electrochemical oxidation of sulfamethoxazole.The new method of detecting sulfamethoxazole was established by differential pulse voltammetry accordingly.Sulfamethoxazole has a obvious oxidation peak at 0.940V.The linear range of the method was 1.00×10-6 to 1.00×10-4 mol/L.The method was applied for sulfamethoxazole determination in seawater with the recovery of 97.7%-105.3%.