Construction Of Carbon Nanocomposite Sensor And Its Application In Detection Of Drugs And Illegal Additives

As an important analytical method in drug analysis,sensor technology is widely used in the field of drug and food because of its fast response,simple operation and high sensitivity.In recent years,carbon nanomaterials have become a research hotspot in many fields due to their many excellent physical and chemical properties.Among them,the funcitionalized carbon nanomaterials have been widely used for sensor construction because of their higher stability,stronger selectivity and electrocatalytic activity.Based on the excellect properties of carbon nanomaterials,five different sensor platforms based on functionalized carbon nanocomposites were constructed and applied to the detection of drug and food illegal additives.In this paper,the reseach is made up of five parts:1??-CD–GO composite film was immobilized on a glassy carbon electrode?GCE?to prepare an electrochemical sensor for simultaneous determination of Imperatorin?IMP?,Isoimperatorin?IIMP?and Umbelliferone?UB?for the first time.The electrochemical behaviors of the three components were investigated by cyclic voltammetry?CV?,electrochemical impedance spectroscopy?EIS?and differential pulse voltammetry?DPV?.The calibration curves for IMP,IIMP and UB were obtained in the range of 2.5-90.0?M,3.0-90.0?M and 0.8-20.0?M with the limits of detection of 0.5,0.8and 0.05?M?S/N=3?,respectively.The modified electrode was successfully applied for the simultaneous determination of IMP,IIMP and UB in traditional Chinese medicine Angelica dahuricae Radix and Duliang Diwan with excellent recoveries as confirmed by HPLC methods.2?DNA/carboxyl MWCNTs was immobilized on a glassy carbon electrode?GCE?to prepare an electrochemical sensor for simultaneous determination of liquiritigenin?LG?and liquiritin?LQ?for the first time.The adsorptive voltammetric behaviors of LG and LQ on DNA/carboxyl MWCTs composite film modified GCE were investigated using DPV,CV and EIS.The calibration curves for LG and LQ were obtained in the range of 0.08-1.6?M and 5.0-100.0?M with the detection limits of 0.02 and0.8?M?S/N=3?,respectively.The method was applied successfully for the dectection of LG and LQ in human blood serum with excellent recoveries.It provides a new tool for the research of the pharmacologiclogical mechanism of LG and LQ in vivo.3?The glassy carbon electrode modified with ZnCl₂@?-CD-GO composite was prepared by drop coating and applied to the simultaneous detection of xanthotoxin?XAT?and bergamot lactone?BG?.The results showed that the ZnCl₂@?-CD–GO/GCE electrode had good electrocatalytic activity for XAT and BG.The linear ranges of XAT and BG on the modified electrode were 0.8-100.0?M and 2.0-100.0?M,respectively,and the detection limits were 25.0nM and 0.2?M?S/N=3?,respectively.In addition,the electrode has good stability and reproducibility for the analysis of XAT and BG,and can be applied to the simultaneous detection of XAT and BG in blood samples.4?DNA was immobilized on a glassy carbon electrode?GCE?modified with graphene oxide?GO?to prepare an electrochemical sensor for sensitive determination of MTX for the first time.The adsorptive voltammetric behaviors of MTX on DNA sensor were investigated using DPV.The peak current response of guanine in DNA was used as a determination signal of MTX in acetate buffer solution.Voltammetric investigation revealed that the proposed method could determine MTX in the concentration range from 0.055-2.2?M with a lower detection limit of7.6nM?S/N=3?.Compared with the previous studies,the DNA/GO/GCE electrode constructed by us based on the change rate of guanine current?R%?in DNA,proportionally reflecting the MTX concentration,is simple and sensitive.5?CuFeS₂ was synthesized by a solvothermal method.The results showed that nano-chalcopyrite had a peroxidase-like activity and can enhance its catalytic acticity after GR-CuFeS₂ complex was formed.Basd on GR-CuFeS₂ composite,a colorimetric sensor with high selectivity and high sensitivity for detecting melamine was constructed.The results showed that linear range of the sensor for detecting melamine was 0.05-1.8?M and the detection limit was 8.0nM.In addition,the sensor has been successfully applied to the determination of melamine in milk power with satisfactory recoveries.