Construction Of Liquid Sers Quantitative Analyzer And Its Application In Molecular Sensing

In recent years,with the development of nano-materials,SERS technology has been increasing trend towards ripeness,which is widely used in many fields,especially for food safety and biological sciences.Gold nanorod(GNR)is one of the best material used to assemble SERS substrate because of its excellent lightning-rod effect and its surface plasmon resonance(SPR)features can be easily tuned from visible to infrared spectrum,just by controlling their length/diameter ratio.It can easily match with the longer laser wavelength equipped on portable Raman devices.This thesis focused on the following areas:In chapter 2,a reversible chloroform/water(O/W)encasing in a cuvette was determined just by the surface wettability of the container and showed attractive SERS capability.Citrate-capped gold nanorod(Ci-GNR)sols were prepared through a polymer-mediated surfactant exchange.The vigorous mixing of chloroform with Ci-GNR sols triggered the rapid self-assembly of GNRs at the O/W interface and produced a metal liquid-like brilliant golden droplet.This platform was self-healing,robust,reproducible,and fabricated without any inducers or modifiers,and Ci-GNRs ensured a “clean” plasmonic surface.In chapter 3,the chloroform molecule itself generated a stable SERS fingerprint peak and could be used as an inherent internal standard(IS)for quantitative SERS analysis.Thiabendazole(TBZ),an oil-soluble broad-spectrum fungicide without resonance Raman effects,was used as the targeted analyte.Both O-in-W and W-in-O platforms exhibited excellent SERS sensitivity and reproducibility on a portable Raman device with a laser line of 785 nm.Moreover,the O phase could act as an extractant to separate and concentrate oil-soluble TBZ from fresh juice with fewer impurities and realized the quantitation of TBZ in complex media with a detection limit far lower than the national standard.Furthermore,reliable SERS analysis was realized for various Raman resonance dye molecules,and targeted analytes dissolved in both O and W phases could be distinguished at sub-ppb levels.This study paves the way toward practical and quantitative liquid-state SERS analysis in a common cuvette and it would be far superior to typical solid substrate-based or nanoparticle sol-based analysis.In chapter 4,A SERS probe based on gold nanorods were synthesized to detect HNO.First,m PEG-SH was used as capping materials,GNRs was transferred from water to organic phase and its stability and monodispersibility are maintained.In addition,LPD was synthesized by using lipoic acid,p-phenylenediamine and 2-diphenylphosphine benzoic acid as raw materials,and then connected to the surface of gold nanorods as Raman report molecules.UV,HLPC and SERS experiments have confirmed that LPD can specifically identify HNO.This provides a new way to detect HNO in cells and tissues.