The Fabrication And Investigation Of Electrochemical Sensor For The Detection Of Taxifolin

As an important kind of flavonoids,taxifolin possesses a variety of biological and pharmacological activities which has preventive and therapeutic effects on human diseases.Taxifolin is also precious raw material to produce medicine,food and health care products.Electrochemical analysis technology has the characteristics of fast detection speed and low cost.Chemical modification of the working electrode is one of the effective ways to improve the sensitivity and selectivity of electrochemical analysis.The preparation of electrode materials with excellent performance is the prerequisite for the functional modification of the electrode surface.In this thesis,a series of materials such as metal-organic framework compounds,molybdenum disulfide,and layered double hydroxides were used as electrode modification materials to construct a taxifolin electrochemical sensor.The main research contents are as follows:?1?To construct an electrochemical sensor for the detection of taxifolin,Ni-MOF and carbon nanotube composite electrode materials were prepared by in-situ self-assembly of nickel-based metal organic framework?Ni-MOF?on the surface through hydrothermal method after activation treatment of multi-walled carbon nanotubes with concentrated acid.The experimental results show that the redox reaction of taxifolin on the surface of Ni-MOF@CNTs electrode is an isoelectron and proton process.The differential pulse voltammetry?DPV?test showed that the detection linear range of the electrochemical sensor was 4×10^-8?1×10^-55 mol L^-1,and the detection limit was 1×10^-88 mol L^-1.In addition,it shows good reproducibility,stability and selectivity.Therefore,the analytical method established by the electrode material Ni-MOF@CNTs can be used to detect taxifolin.?2?Molybdenum disulfide and activated nitrogen-doped porous carbon composites were prepared to construct a taxifolin electrochemical sensor.The results show that the redox reaction of taxifolin on the surface of MoS₂/ANC electrode is a kinetic process controlled by adsorption and diffusion,and its saturated adsorption capacity is 4.6×10^-99 mol cm^-2.The electrochemical sensor has a wide linear detection range(1×10^-9?1×10^-6 mol L^-1)and a lower detection limit(3×10^-10 mol L^-1).This sensor was used to detect the content of taxifolin in the actual sample of fructus polygoni orientalis,Repeated three measurements showed that the recovery range was 98.9?100.5%.The above results indicate that the prepared MoS₂/ANC composite is a potential electrode material for the detection of taxifolin.?3?A layered bimetal hydroxide of zinc and cobalt was prepared by a hydrothermal method,and further derivatized to prepare a MOF material.Then,the response performance of the electrochemical sensor constructed by this electrode material to taxifolin was systematically studied.Electrochemical analysis showed that the redox reaction of taxifolin on the surface of the ZnCo-LDHs-MOF electrode was also the coexistence of adsorption-diffusion,and the number of electrons gained and lost in the process was also two.This sensor not only has good reproducibility,stability,selectivity,etc.,but also shows a wider linear detection range(7×10^-10?1×10^-6 mol L^-1)and lower detection limit(2×10^-10mol L^-1).The above results show that the ZnCo-LDHs-MOF electrochemical sensor has good electrochemical response performance to taxifolin.