Construction Of Electrochemical Sensors Basing On Carbon Nanocomposites In Determination Of Certain Drugs

At present,the importance of drug quality testing has attracted more and more attention.All countries in the world have listed drug quality testing technologies as important development areas.Research on analytical instruments related to drug testing has been a research hot topic,and this trend will continue to develop.Chemically modified electrodes represent a modern advancement in electrode systems and are currently active in electrochemical and electroanalytical chemistry.The modified electrode has the advantages of high selectivity,fast analysis speed,simple operation and low price.It has been widely used in environmental monitoring,food industry,clinical diagnosis and other fields.In this paper,the functionalized electrochemical sensor based on the preparation of multi-walled carbon nanotubes is applied to the electrochemical sensing analysis of metronidazole(MND),myricetin,rutin and chlorogenic acid(CGA)to improve the detection sensitivity and selective.The specific conclusions are as follows:(1)An ultrasensitive electrochemical sensor based on polydopamine/carboxylic multi-walled carbon nanotubes(MWCNTs-COOH)nanocomposites modified glassy carbon electrode(GCE)was prepared by simple drop coating and electropolymerization method.The surface structure of the electrode was characterized by scanning electron microscopy,and its electrochemical characteristics were studied by electrochemical methods.Compared with bare GCE,the polydopamine/MWCNTs nanocomposites modified electrode has good electrochemical response to metronidazole.Under the optimization conditions,the quantitative detection result of differential pulse voltammetry showed a wide linear detection range from 5 to 5000 ?M and a low detection limit of 0.25 ?M(S/N=3).Moreover,the proposed sensor has been successfully applied for the quantitative determination of metronidazole in real drug samples.This work may provide a novel and effective analytical platform for determination of metronidazole in application of real pharmaceutical and biological samples analysis.(2)Constructed via facile electrochemical method a synthesis of multi-walled carbon nanotubes,reduced graphene oxide and platinum(Pt@r-GO @MWCNTs)nanoparticles ternary composite nanomaterials.The composite was modified on a glass carbon electrode,Characterization of prepared ternary composite nanomaterials(Pt@r-GO@MWCNTs)via scanning electron microscopy and Energy dispersive X-ray spectroscopy(EDS)techniques,and electrochemical characteristics investigations carried out by cyclic voltammetry(CV),differential pulse voltammetry(DPV).Compared with the bare GCE,the Pt@r-GO@MWCNTs/GCE has significant electrochemical response myricetin and rutin.Under the optimization conditions,The quantitative determination of myricetin and rutin by Pt@r-GO@MWCNTs/GCE exhibit a wide linear range and lower detection limits.The oxidation peak currents of myricetin is proportional to the concentrations of myricetin in the linearity of ranging from 0.05-50 ?M with a detection limit of 0.005?M(S/N=3).and for rutin linear ranging from 0.05-50 ?M with a detection limit of 0.01?M(S/N=3).The sensor also exhibits good reproducibility and stability,and has been successfully used for the simultaneous determination of myricetin and rutin in real orange juice samples with the recoveries between 100.6% and 108.5%.(3)The electrochemical sensor based on multi-walled carbon nanotubes,reduced graphene oxide and platinum(Pt@r-GO@MWCNTs)nanoparticles ternary composite nanomaterials modified glassy carbone electrode was fabricated by a simple and convenient one-pot method,and electrochemical response to chlorogenic acid was studied under the different conditions.Compared with GCE,The modified electrode has a good electrochemical response to chlorogenic redox reactions,and the electrode significantly sensitive for the detection of chlorogenic acid and appears wide linear detection ranges at low concentration from 0.005 ~ 2 ?M and at high concentration from 2-20 ?M,with the accumulation time of 150 s,in pH 6.0 0.1M PBS solution.The detection limit is 0.001?M(S/N=3).Furthermore,The sensor also has good reproducibility and stability,and has been successfully used to detect the content of chlorogenic acid in actual serum samples,and the recovery rate is between 98.7 % and 104.3 %.