Studies On The Determination Of Environmental Endocrine Disrupting Chemicals Based On Novel Chemically Modified Electrodes

Enviromental endocrine disrupting chemicals(EDCs)are exogenous agent that interferes with synthesis,secretion,transport,metabolism,or binding action of natural blood-borne hormones that are responsible for homeostasis,reproduction,and developmental processes.It will be very important to establish a simple,rapid,sensitive and reliable analytical method for the determination of EDCs,which are lower in the enviromental but harmful to organism.This paper studied on the determination of environmental endocrine disrupting chemicals,such as Cr(?)and phenol pollutants,based on novel chemically modified electrodes.The present method provides to be simple,sensitive,good reproducibility and stability.The main contents and conclusions are as following:The silver nanoparticles-coated gold nanoporous film electrode(AgNP/AuNF)has been prepared and used in the amperometric detection of Cr(?)successfully.The prepared AgNP/AuNF electrode was characterized by scanning electron microscopy(SEM),energy dispersive X-ray(EDX)spectroscopy and cyclic voltammetry(CV).The AgNP/AuNF electrode exhibited large electroactive area and showed outstanding sensitivity and favorable reproducibility for Cr(?)detection.The dependence of reduction current on Cr(?)concentration is linear from 2 to 54 ?g/L(ppb)and 25 to 380 ?g/L(ppb)with a low detection limit of 0.65 ppb.The present method provides to be rapid,reliable,sensitive and low-cost.Electrochemical sensor for bisphenol A(BPA)based on molecularly imprinted technique(MIT)was prepared by the approach of self-assembly and electropolymerization using BPA as template molecule and 2-aminothiophenol(ATP)as functional monomer.Cyclic voltammograms(CV)and electrochemical impedance spectroscopy(EIS)were employed to probing the features of the modified electrode.Due to the electrical activity of BPA,the polymerization of BPA also occurred within the potential range of electropolymerization of ATP on the electrode.After the removal of BPA,the cavities can not be produced in the polymembranes or the cavities can not match with the template BPA molecules,which result in the fuilure of quantitative determination of BPA.This results provided a theoretical basis for the correctly selecting functional monomer and template molecule to establish molecular imprinted polymers using electropolymerization.A simple and sensitive electroanalytical method for the determination of bisphenol A(BPA),4-octylphenol(OP)and 4-nonylphenol(NP)based on multi-walled carbon nanotubes modified glassy carbon electrode(MWCNT/GCE)was presented.Factors influencing the detection processes,such as pH,scan rate and accumulation time were optimized.The oxidation peak current of all the three analytes were significantly enhanced by MWCNT/GCE compared with those of bare glassy carbon electrode.Under the optimal conditions,the oxidation peak current was proportional to the concentration of BPA in the linear range of 0.05?10 ?mol/L and 20-100?mol/L with the correlation coefficient of 0.9958 and 0.9922 and with the low detection limit of 0.013 ?mol/L.The oxidation peak current was proportional to the concentration of OP in the wide linear range of 0.05?10 ?mol/L with the correlation coefficient of 0.9986 and the low detection limit of 0.015 ?mol/L.The oxidation peak current was proportional to the concentration of NP in the wide linear range of 0.05?8 ?mol/L with the correlation coefficient of 0.9974 and the low detection limit of 0.023 ?mol/L.The reproducibility and stability of the modified electrode were also tested.It was found that the relative standard deviations(R.S.D)on the modified glass carbon electrode for 10 replicate determination was less than 5%indicating excellent reproducibility.The stability of the modified electrode was excellent with the current response only decreased to 98%after 10 days,while 90%of the initial response retained after 20 days.The method exhibited some obvious advantages,such as simple preparation process,low cost,high sensitivity,good stability and reproducibility,suggesting that it has a potential application for trace phenols detection in environment.