Simultaneous Detection Of Phenolic Substances By Electrochemical Sensors Based On Carbon-based Nanocomposites

Phenolic compounds are widely found in the environment.They are important industrial chemicals that cause environmental pollution,which seriously endanger the people’s health and ecological environment.Therefore,the development of detection methods for phenolic compounds has always been a research hotspot.Electrochemical methods have the advantages of fast response,simple operation and low cost;therefore,the electrochemical methods have great application prospects in the detection of phenolic substances.In this study,two new electrochemical sensors were prepared using different nanocomposites for the simultaneous determination of phenolic substances.The main contents are as follows:1.A one-step hydrothermal method was used to prepare molybdenum disulfide(MoS2)and carboxylated graphene(GR-COOH)composites.A novel electrochemical sensor for simultaneous detection of benzenediol isomers was prepared.The morphology of the composites was characterized by transmission electron microscopy(TEM)and scanning electron microscopy(SEM).Electrochemical impedance spectroscopy(EIS)was used to characterize the electron conductivity of the surface of the modified electrode.The electrocatalytic properties of the sensor for hydroquinone(HQ),catechol(CC)and resorcinol(RS)were investigated by cyclic voltammetry(CV)and differential pulse voltammetry(DPV).The research shows that the modified electrode has good catalytic and separation effects on the oxidation of three benzenediol isomers,and can realize the individual and simultaneous determination of the three benzenediol isomers.In addition,the sensor has the advantages of stability,reproducibility,good selectivity,and simple preparation method,and can be used for the detection of real samples.2.N-MWCNTs-COOH/GO/GCE modified electrode was prepared by drop-casting the mixture of nitrogen-doped multi-walled carbon nanotubes(N-MWCNTs)and graphene oxide(GO)onto the surface of the treated glassy carbon electrode.Electrochemical experiments show that the modified electrode has a significant catalytic effect for o-aminophenol(o-AP)and p-aminophenol(p-AP),and can significantly increases the oxidation peak current of each substance compared with the bare glassy carbon electrode.It improves the separation effect of adjacent oxidation peaks and can be used for simultaneous determination of o-AP and p-AP.The sensor has good stability,reproducibility,good selectivity,high sensitivity,and is easy to prepare.It is used for the detection of actual samples with satisfactory results.