Development Of Electrochemical Sensor For Nano-metal Hybrid Carbon Material And Its Application In Traditional Chinese Medicine Analysis

As the basis of electrochemical sensing,Chemically Modified Electrodes(CMEs)is the most active areas of research in current electrochemical,electroanalytical chemistry.Since its inception,CMEs has become an important research in the field of analytical chemistry.In analytical applications,CMEs has the following advantages:(1)the surface of the electrode can be modified according to the specific functional groups,with different types and special functions modified our electrodes;(2)the basic electrode material can be metal,nonmetal,organic,and also can be a conductor,semiconductor,all the materials provide a basis for the development of new electrical analysis of chemical;(3)according to different electrode modified functional groups,which can present selective responses for our target objects;(4)modified electrodes can enhance the reversibility of electrode reaction,open up new avenues for electrode process kinetics study;(5)the sensitivity of the modified electrode is much greater than that of the bare electrode,which provides a strong effect on the further development of trace analysis.It is because of these advantages,CMEs have a broad application prospects in many areas.Carbon nanotubes and graphene have high specific surface area,unique characteristics of spatial structure,easy to be functioned and modified.And nano-metal material has the characteristics of electron transfer rate,both for electrochemical effects have promote role.This study constructed three kinds of nanometer metal hybrid carbon nanotube modified electrochemical sensor,applied in the traditional Chinese medicine analysis.The content of the thesis mainly divided into the following three parts: 1.Electrochemical behaviors and analytical application of Tetrahydropalmatine in NiNPs/SGS modified glassy carbon electrode.A glassy carbon electrode(NiNPs/SGS/GCE)modified by nano metal nickel/ sulfonated graphene was prepared.The surface and metal properties of the modified electrode were characterized by scanning electron microscopy,energy spectrum analysis and photoelectron spectroscopy.The electrochemical behavior of Tetrahydropalmatine(THP)was studied by using the modified electrode.The results show that sulfated graphene has good electrochemical effect on THP,and nano-nickel can further enhance the oxidation peak current of THP and promote its electron transfer efficiency on the surface of modified electrode.Under the optimum conditions,the peak current of THP oxidation peak was linear with the concentration of 5.0×10-7~2.0×10-5 mol/L,r was 0.9988,and the detection limit was 1.7×10-7 mol/L(S/N=3).And the modified electrode was successfully applied to the determination of THP in Yuanhu Zhitong Capsule.2.Electrochemical behavior of mangiferin and icariin on nanogold and silver-carbon nanotube sulfonated graphene modified glassy carbon electrode and its application.Carbon nanotube sulfonated graphene(MWNTs-SGSs)and gold-silver nanoalloy(Au-AgNPs)were modified on the surface of glassy carbon electrode(GCE)by drop coating method,and a new electrode was developed.The modified electrode combines the planar two-dimensional structure of graphene,the tubular three-dimensional structure of carbon nanotubes and the special electrochemical effect of nano-metal,not only increases the effective surface area of the modified electrode,but also enhances the electron transfer rate of the electrode surface Mangiferin(MIN)and icariin(IIN).In the experiment,the surface morphology of the modified electrode was characterized by cyclic voltammetry(CV),differential pulse voltammetry(DPV),time-dependent coulomb on MIN and IIN on the modified electrode by scanning electron microscopy and infrared behavior to examine.It was found that Au-AgNPs/MWNTs-SGSs/GCE showed excellent selectivity and catalysis for the electrochemical behavior of MIN and IIN.The cyclic voltammetry potentials were optimized at 0.56 V and 0.95 V,respectively.The linear range of oxidation peak current and concentration of MIN and IIN was 5.0×10-8~5.0×10-4 mol/L and 5.0×10-8~5.0×10-4 mol/L,the linear coefficients were 0.9995 and 0.9991,the detection limit was 1.7×10-8 mol/L.In the actual sample determination,Au-AgNPs/MWNTs-SGSs/GCE can be successfully applied in the determination of Anemarrhena,capillaris and epimedium,and the results are satisfactory.The method has the advantages of low reagent dosage,low analytical cost,high sensitivity and good reproducibility.It is a new method for simultaneous determination of active ingredients of MIN and IIN.3.Molecular analysis and application of nano-silver hybrid carboxylated carbon nanotubes modified glassy carbon electrode for dipterex.AgNPs/MWNTs-COOH/GCE were successfully deposited on the glassy carbon electrode coated with carboxylated carbon nanotubes(MWNTs-COOH)by potentiostatic deposition.Compared with bare GCE,AgNPs/GCE,MWNTs-COOH/ GCE,hybrid material modified electrode has stronger electrocatalytic effect.The AgNPs/MWNTs-COOH/GCE developed in the experiment had higher response current to trichlorfon and showed good selectivity,stability and repeatability.In the range of 1.9×10-9~3.77×10-6 mol/L,there is a good linear relationship,r was 0.9991.The detection limit of trichlorfon was 6.2×10-10 mol/L.In the determination of the actual sample(lonicara japonica and dried orange peel),the results showed a high sensitivity,the recovery rate of 99.3%,repeated in several tests RSD were less than 5%.