The Study Of Electrochemical Multiple Detection Performance Based On Carbon Nanocomposites

In recent years,people have been paying much attention to the pollution of the environment,so it is very important to choose the sensitive and rapid technical methods for the environmental monitoring.Electrochemical sensors are often used in the fields of environment,medicine and food because of their advantages of on-site detection,easy operation,sensitivity and economical application.However,because of its weak electrical activity in electrochemical sensor,bare GCE usually needs to be modifed using different materials so as to improve its electrochemical performance.In this paper,three novel sensors for sensitive detection of environmental organic pollutants was constructed using several carbon-based nanocomposites as electrode materials.（1）Firstly,three differentβ-CD functionalized MWCNT-COOH composites were respectively synthesized by Steglich esterification method,ultrasonic mixing method and electrochemical polymerization method,i.e.,C_m@M（m=1.0,1.5,2.0）,C/M and E₃₀-M.Then,these materials were characterized by FT-IR,SEM,XRD and electrochemical methods.It was found that the composite E₃₀-M synthesized by electrochemical polymerization had the strongest recognition ability for p-NT molecules,while C_1.5@M in C_m@M showed better electrochemical activity.Next,β-CD was electrochemically polymerized on the C_1.5@M modified electrode to obtain E₃₀-C_1.5@M.The detection ability of the sensor based on E₃₀-C_1.5@M for p-NT was significantly enhanced,showing a good linear relationship in the concentration range of 0.66～11.88μM,and its LOD=0.485 nmol/L.And the sensor also enables sensitive simultaneous detection of p-NT,p-NP,and o-NP without interference.（2）ZM nanocomposites were prepared by ultrasonic mixing of C@Zr O₂and MWCNTs-COOH,and ZM/GCE modified electrodes were obtained based on this material.ZM/GCE has a good ability to recognize APAP and can promote the chemical reaction of APAP molecules on the electrode surface.The peak current intensity of APAP is 22.5 times that of the bare electrode and 1.5 times that of MWCNTs-COOH/GCE,its LOD=0.06μM.ZM/GCE can also detect APAP,HQ and CC simultaneously with good peak-to-peak separation among them without interfering with each other.ZM combines the advantages of C@Zr O₂and MWCNTs-COOH with excellent stability,reproducibility,electron conduction rate and molecular recognition.（3）The nanocomposite r GE of Eu₂O₃and r GO was prepared step by step by ultrasonic mixing and electrochemical reduction.Since the introduction of Eu₂O₃greatly weakened the aggregation of r GO,and increased the active surface area and conductivity of r GE.Compared with GO/GCE,r GO/GCE,Eu₂O₃/GCE and GE/GCE,the r GE/GCE sensor has the strongest recognition ability for 2,4-DNP.2,4-DNP undergoes a complex redox reaction on r GE/GCE,and two rare irreversible reduction peaks and a pair of reversible current peaks appeared,its LOD is 0.32μM in the concentration range of 13～104μM.The r GE/GCE also achieves sensitive dual electrochemical detection of 2,4-DNP and o-NP.In conclusion,in conclusion,several electrochemical sensors were constructed using carbon-based nanocomposite in this paper,they all have the advantages of long storage time,good reproducibility and low detection limit,and can realize multiple sensitive detection of some aromatic hydrocarbon compounds in environmental organic pollutants.