The New Colorimetric And Fluorescent Methods For The Determination Of Trace Component Based On The Local Surface Plasmon Resonance Of Gold Nanoparticles

Gold nanoparticles have attracted widespread research concern due to their unique physical and chemical properties,and exhibit potential applications in various fields such as materials science,analytical chemistry and so on.Among their inherent characteristics,the local surface plasmon resonance?LSPR?properties cast light on a considerable advantage of gold nanoparticles in constructing optical probe which are widely applied in monitoring all kinds of molecules.In the present thesis,a brief review of the preparation,optical properties and applications of gold nanoparticles was presented.In the following chapters,the author's main research works centered on LSPR property of the gold particles during the study of master's degree are presented in detail.This dissertation consists of four chapters,and a brief introduction is outlined as follows:Chapter 1:This chapter reviewed the preparation methods and excellent optical properties of gold nanomaterials as well as their applications in detection of various analytes.Chapter 2:A rapid,sensitive and colorimetric method for the determination of ornithine has been developed.The two amino groups of ornithine could strongly interact with the Hg²⁺layer which was coated around Au NPs.Therefore a bridge between Au NPs was formed and caused their aggregation.And a new red-shifted intense peak appeared in the absorption spectra with the color of the Au NPs solution changing from red to purple.Under the optimal conditions,the linear range of the present method was 0.1-0.25 mmol/L with the detection limit of 50?mol/L.The developed method was successfully applied to determine the amount of ornithine in plasma samples.Chapter 3:In this chapter,a sensitive and visual method for the detection of sulfite has been established on the principle that the aggregation of Au NPs functionalized by cysteine was inhibited by H₂O₂,while in the presence of sulfite,H₂O₂ was consumed and the inhibition was decreased.Under the optimal conditions,the linear range of the present method was of 0.5-16?mol/L with the detection limit0.2?mol/L.The proposed method exhibits great potential for detection of sulfite and was successfully applied to determine the amount of sulfite in haw roll samples.Chapter 4:Au-peptide-FITC beacon was prepared and the fluorescence of FITC was quenched on the basis of FRET between FITC and Au NPs.The present method took advantage of the enzymatic digestion of trypsin on the peptide,causing the release of FITC from the Au NPs,which was accompanied by fluorescence recovery,thus a highly sensitive and selective fluorescence method for detection of trypsin was successfully established.Under the optimal conditions,the linear range of the proposed was 10-100 nmol/L with the detection limit of 5 nmol/L.The method was successfully applied to determine the amount of trypsin in plasma samples.