Application Of Electrochemical Sensor Of Antibiotics Based On Molybdenum Disulfide Nanocomposite

Antibiotics are effective drugs for the treatment of bacterial infections.However,the large-scale use of antibiotics in human medicine and agricultural production has promoted the rapid spread and spread of bacterial resistance in the environment,especially the common use of multiple antibiotics has prompted the emergence of multiple drug resistance,which is a serious threat to human beings.Electrochemical sensing technology has attracted the attention of researchers due to its unique detection and analysis methods and its wide application in clinical diagnosis.Compared with other detection methods such as capillary electrophoresis,high performance liquid chromatography and liquid chromatography-tandem mass spectrometry,the electrochemical sensor overcomes the disadvantages of high cost and complicated operation,and is an ideal in vitro detection device.The unique physical and chemical properties of MoS₂and its nanocomposites,such as high mechanical strength,high carrier transport,large surface area,excellent conductivity and fast electron transport rate,make it a good load in substrates for a variety of electrochemical applications.In this thesis,based on molybdenum disulfide/nanocomposite materials,the following research work is carried out:(1)Electrochemical detection of chloramphenicol with nitrogen-doped molybdenum disulfide supported palladium nanoparticles.Heteroatom doping is one of the effective methods to improve the surface properties of MoS₂.In the current work,a new type of nitrogen-doped MoS₂-supported palladium nanoparticles(N-MoS₂/PdNPs)was proposed through a simple hydrothermal method.The N-MoS₂/PdNPs thus obtained were characterized by transmission electron microscope(TEM),ultraviolet spectroscopy(UV-Vis)and X-ray photoelectron spectroscopy(XPS).It is found that N-MoS₂/PdNPs modified glassy carbon electrode(GCE)can significantly enhance the catalytic performance of chloramphenicol,with a linear response range of5.0?M-2000?M,the detection limit as low as 1.97?M(S/N=3).The promising sensor of the present invention exhibits high sensitivity,good stability,remarkable reliability,repeatability and satisfactory recovery rate for electrochemical detection of CAP in pure milk samples.(2)Electrochemical detection of tetracycline by gold nanoparticles@molybdenum disulfide/chitosan compositeA gold nanoparticle/molybdenum disulfide/chitosan nanocomposite(Au@MoS₂/Ch)was successfully synthesized by a simple ultrasonic method,and modified to a glassy carbon electrode to construct an electrochemical sensor to detect tetracycline.Electrochemical experiments show that,compared with pure MoS₂or Au nanoparticles,Au@MoS₂/Ch exhibits enhanced electrocatalytic activity for the oxidation of tetracycline.Based on differential pulse voltammetry(DPV),the sensor is used for the detection of tetracycline,with a detection limit as low as 0.41?M(S/N=3),and linear ranges of 1-1100?M and 5-1100?M.In addition,this electrochemical sensor shows high stability and good selectivity.Finally,the electrochemical sensor is applied to milk determination,which can be used for actual sample detection.(3)Electrochemical detection of enrofloxacin by molybdenum disulfide/multi-wall carbon nanotube compositeThe Ch-MoS₂-MWCNTs nanocomposite was prepared by ultrasonically dispersing multi-walled carbon nanotubes(MWCNTs)into an aqueous dispersion of molybdenum disulfide(MoS₂),which was dispersed in an aqueous solution of chitosan with the aid of ultrasound.The resultant has low electron transfer resistance,high effective surface area,and excellent membrane electrode stability.In this paper,a simple method for electrochemical determination of enrofloxacin(ENRO)and its main metabolite ciprofloxacin(CIPRO)was constructed by modifying the material on a glassy carbon electrode.Under the optimal conditions of pH 7.0,the current increases linearly with the concentration of ENRO and CIPRO in the range of 0.05?M-40?M and 0.2?M–30?M,and the detection limits are 0.05?M and 0.16?M.The proposed method is used to determine enrofloxacin in milk.