Based On Carbon Nanocomposites Of Electrochemical Sensor For The Determination Of Insecticidal Pesticides

Electrochemical sensing is a simple and convenient detection method with high accuracy,fast response,which is often used in food detection,environmental pollutant monitoring and human blood drug detection.The catalytic performance of electrochemical sensors can be improved by preparing carbon nanocomposites with different properties to construct modified electrodes.On the one hand,the surface of two-dimensional layered graphene and hollow carbon nanotubes possesses abundant functional groups and active sites.On the other hand,metal oxide hydroxide and transition metal have good electrical conductivity and high electrochemical performance.This paper employs two simple methods to prepare four kinds of carbon nanocomposite materials with excellent performance,and constructs four kinds of electrochemical sensors for the determination of insecticidal pesticides.The main work carried out is as follows:（1）Co（OH）₂-MWCNTs composites were prepared via a simple hydrothermal method to construct Co（OH）₂-MWCNTs/GCE for the determination of matrine.The electrocatalytic behaviors of matrine on Co（OH）₂/GCE,MWCNTs/GCE and Co（OH）₂-MWCNTs/GCE were studied by means of AC impedance（EIS）,differential pulse voltammetry（DPV）and cyclic voltammetry（CV）.The results showed that the selective determination of matrine on Co（OH）₂-MWCNTs/GCE in 0.2 M PBS buffer with p H 7.0 could be achieved by using DPV test method.The detection range was 1.0～240μM and the detection limit was 0.55μM（S/N=3）.（2）Ni/Al-LDH/GO composite material has been prepared by fixing Ni/Al-LDH lamellar slices on GO slices with large specific surface area via high temperature hydrothermal method to construct Ni/Al-LDH/GO/GCE for the determination of tessurb（MB）.The electrochemical behavior of GO/GCE,Ni/Al-LDH/GCE,Ni/Al-LDH/GO/GCE of modified electrodes for detection of MB was studied and compared by means of EIS,CV and DPV.The experimental results showed that Ni/Al-LDH/GO/GCE could achieve the selective determination of MB in 0.2 M PBS buffer solution with p H 7.0 and the catalytic effect is outstanding.The detection range was 1.0～19.0μM and the detection limit was 0.088μM（S/N=3）.（3）Nitrogen-doped MWCNTs（N-MWCNTs）composites modified with Mo S₂ nanoparticles were prepared by high temperature calcination method to construct modified electrodes（Mo S₂/N-MWCNTs/GCE）for the determination of chloranobenzamide（CAP）.EIS,CV and DPV were used to test Mo S₂/GCE,N-MWCNTs/GCE and Mo S₂/N-MWCNTs/GCE testing the electrochemical performance of CAP.The results show that the peak oxidation potential of CAP on Mo S₂/N-MWCNTs/GCE in 0.2 M PBS buffer with p H 7.0 is 0.32 V.The detection range was 1.4～100μM and the detection limit was 0.03μM（S/N=3）.（4）WSe₂/GO composite two-dimensional carbon nanomaterials were prepared by means of hydrothermal first and high-temperature calcination,which were used to construct WSe₂/GO/GCE.The electrochemical behavior of thiazinone on GO/GCE,WSe₂/GCE and WSe₂/GO/GCE was investigated by EIS,CV and DPV,and the performance difference of thiazinone was compared and detected.The experimental results showed that selective determination of thiazinone on WSe₂/GO/GCE in 0.2 M PBS buffer with p H 7.0 could be achieved by DPV test.The detection range was 15.0～120.0μM and the detection limit was 6 n M（S/N=3）.In conclusion,four functional carbon-based nanomaterials,Co（OH）₂-MWCNTs,Ni/Al-LDH/GO,Mo S₂/N-MWCNTs and WSe₂/GO,were prepared in this paper and used to construct electrochemical sensors for the determination of insecticidal pesticides.The results exhibited that the four carbon nanocomposite modified electrodes showed high electrocatalytic activity and selectivity to the corresponding insecticidal pesticides.