Study On The Application Of Electrochemical Sensor Based On Gold Doped Nanomaterials

In recent years,The rapid development of electrochemical sensors brings dramatical convenience for people in many respects,such as drugs testing in real time,direct monitoring for environmental pollutants,rapid detection of food safety,and so on.At the same time,electrochemical sensors ought to meet higher demand when facing biosystem of complexity,especially in selectivity,sensitivity,accuracy,biocompatibility and stability.For the sake of improving performance,there are two ways in general.One is to prepare new-type electrode material,and the other chemically modify electrode.Nanometer materials refer in particular to the materials which span nano scale in one or more dimensionality.Nanometer materials,with rich structure,reveal competitiveness in various domains because of its physics,chemistry,machinery,magnetism,optical properties.Many researches have shown that nanometer materials tremendously improve performance of electrochemical sensors in sensitivity,stability and selectivity.The popular material applied in electrochemical sensors is metal nanometerials,carbon nanomaterials,and semiconductor materials.However,the property of one single kind of nanomaterial is simplex,and cannot satisfy the actual needs.Therefore,in this paper several gold nano composite materials were prepared by some simple methods and used for electrochemical sensor to improve the electrochemical performance.The gold nanocomposite not only has special physical properties,chemical properties,stability,non-toxic,electronic conductivity,biocompatibility properties similar to gold nanoparticles,but also has special performance of the new composite.These characteristics of gold nanocomposite make electrochemical sensor a great improvement in sensitivity,stability and reproducibility.This thesis contains following contents:?1?The preparation and study of the electrochemical activity of Au/VXC72R:Gold nanoparticles-supported Cabot Vulcan XC72R?Au/VXC72R?nanocomposite was synthesized by chemical reduction of gold???chloride with VXC72R.A novel electrochemical sensor based on the Au/VXC72R nanocomposite has been fabricated for the sensitive detection of rifampicin?RIF?.Field-emission scanning electron microscopy?FESEM?,transmission electron microscopy?TEM?,X-ray powder diffractometer?XRD?and X-ray photoelectron spectroscopy?XPS?were used to characterize the morphology,structure and compositions of the nanocomposite.Under the optimal conditions,the Au/VXC72R-chitosan/GCE can be used to determine RIF concentration in a linear range from 5×10^-7 mol/L to 1×10^-5 mol/L with the detection of 1.1×10^-7 mol/L?S/N=3?.The proposed approach exhibits good stability,acceptable reproducibility and applicability,which will probably bring widespread applications in quality monitoring in real samples.?2?The preparation and study of the electrochemical activity of Au-ZnSs:Poly?diallyldimethylammonium chloride?functionalized ZnS were successfully synthesized,and gold nanoparticles?AuNPs?were successfully assembled on the surface of ZnSs via a self-assembly approach.The resulting Au-ZnSs were characterized and expected to offer a promising material for rutin detection because of its satisfactory chemical stability and the good biocompatibility of AuNPs.The i-t approach provided a linear response range between1×10^-7 mol/L and 2×10^-5 mol/L with a detection limit of 1.53×10^-8 mol/L.The Au-ZnSs/GCE used for rutin determinations in real samples with satisfactory results.The proposed electrochemical sensor would provide a simple method for determination of rutin in practical applications.?3?In this section we prepare Au Nanoparticles by the means of Sodium citrate reducing gold???chloride.And then prepare composite film electrode containing gold nanoparticle,K₆P₂W₁₈O₆₂(P₂W₁₈)and SnO₂ by the layer-by-layer self-assembly technique to Myricetin detection.We analyze and compare the response of The cyclic voltammograms current when used for Myricetin detection with different electrode.Then we find the current response of P₂W₁₈-SnO₂-Au Modified ITO electrodes is obviously greater than that of other electrode.We investigate the influence on myricetin electrochemical behavior with different cyclic voltammetry scanning speed.And we optimize the condition of buffer solution PH value in Myricetin detection and the number of layer for composite film.Under the optimal conditions we conduct Myricetin testing.And the results show a commendable linearity in the range of10^-6 mol/L-1.10×10^-4 mol/L with detection limit 6.70×10^-8 mol/L.This developed sensor was successfully applied for the determination of myricetin in real samples.The analysis results indicate that it can act as a promising electrochemical platform myricetin detection.