| Environmental endocrine disruptors are exogenous chemicals that can interfere with endocrine system,cause genital disorders,reproductive capacity decreased,the larvae die,even extinction for animals and humans.It is a serious threat to humans’survival and health.Therefore,it is very important to develop a sensitive,fast and accurate method for the determination of endocrine disruptors.In this paper,we selected the most common types of endocrine disruptors 4-nonylphenol,bisphenol A,cadmium and lead as a typical study,and constructed several electrochemical methods for the rapid detection of these endocrine disruptors in daily food,such as honey,milk,mineral water,and environmental water samples.The main content and results are listed as following:1.Graphene-chitosan(GR-CS)modified glassy carbon electrode(GCE)was prepared by in situ reduction.The obtained electrode was characterized by FT-IR spectroscopy and Raman spectroscopy,and the results showed that the graphene oxide(GO)was deoxygenized successfully.On this basis,the electrochemical behavior of 4-nonylphenol(4-NP)was studied by using cyclic voltammetry and differential pulse voltammetry.It was found that the oxidation current on GR-CS/GCE electrode was significantly larger than on the GCE and GO-CS/GCE electrodes,and the oxidation potential shifted negatively,indicating that the GR-CS/GCE electrode had obviously catalytic activity on the 4-NP’s oxidation.Under the optimized conditions,the oxidation peak current was proportional to 4-NP concentration in the range between 1×10-8 mol/L and 1×10-5 mol/L(R=0.9988).The linear equation was I(μA)=0.364C(μmol/L)+0.618(R=0.9988),with the detection limit of 5.2×10-9 mol/L(S/N=3).Finally,this proposed sensor was successfully employed to determine 4-NP in real samples with a satisfied result.2.Hypercrosslinked resin MN202 was used as material of electrode for the first time,and MN202-GO composites were successfully prepared.The interaction between MN202 and GO was characterized by UV absorption spectroscopy,and the result showed it was π-π stacking.CS/MN202-EGR/GCE electrode was prepared by electrochemical reduction,and was used for the electrochemical detection of bisphenol A(BPA).The relationship between BPA concentration and the oxidation peak current was studied by differential pulse voltammetry(DPV).It showed that BPA concentration was proportional to the oxidation peak current in the range between 5.0×10-9 mol/L and 2.0×10-5 mol/L with a good linear relationship,the linear equation was I(μA)=0.645C(μmol/L)+0.123(R=0.9984),and the detection limit was 1.02×10-9 mol/L(S/N=3).Finally,the proposed electrode was applied for the detection of BPA in milk and mineral water whosed packaged were plastic.The result showed an excellent performance with a recovery between 98.6%and 101.8%.3.In this paper,L-cys/GR-CS/GCE electrode was prepared successfully.The electrochemical properties were investigated by cyclic voltammetry,electrochemical AC impedance,and differential pulse anodic stripping voltammetry,using[Fe(CN)6/Fe(CN)6]3-/4-(1:1)as the probe.The results showed that L-cys/GR-CS/GCE had a good electrical conductivity and a good differential pulse anodic stripping response for Cd2+ and Pb2+.Experimental parameters,such as the deposition potential and time,the pH value of buffer solution were optimized.Under the optimized conditions,the linear equation of the differential pulse anodic stripping response current and Pb2+,Cd2+ concentration were I(μA)=0.745C(μg/L)+4.539(R=0.9986),I(μA)=0.437C(μg/L)+2.842(R=0.9983)respectively,and with the detection limit of 0.45 μLg/L and 0.12 μg/L,respectively.Finally,L-cys/GR-CS/GCE electrode was used to detect Pb2+ and Cd2+ of eight sampling points of Hongze Lake,and the results were compared with ICP-AES.It found that the relative error did not exceed 5%,which indicated that the constructed electrode for the detection of Cd2+ and Pb2+ in water samples was reliable,and it could be used to monitor the Cd2+ and Pb2+ in environmental water samples. |
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