Preparation, Modification Of Gold Nanorods And Their Applications In Surface Enhanced Raman Spectroscopy

Surface Enhanced Raman Scattering?SERS?is a new spectral analysis technique with advantages of high sensitivity,fast and nondestructive detection,which has great potential in determination of trace analytes.SERS can obtain the spectral"fingerprint"peak of the analyte and provide molecular level information with structural features.As SERS signal acquired is directly determined by the SERS substrate,the design and preparation of SERS substrate is very important.Recently,anisotropic metal nanoparticles have aroused widespread concern.In this paper,gold nanorods?AuNRs?and bi-metallic nanoparticles?AuNR@Ag?were synthesized to achieve sensitive and reliable SERS detection of target molecules.The main contents of this article are as follows:First,gold nanorods were prepared by seed growth method,the surface was then cleaned and modified with potassium iodide?KI?to get AuNR@I nanoparticles,which were used as a SERS substrate to detect fipronil.The potassium iodide not only can reduce the surface CTAB amount but also can play the role of salt accumulation,resulting in more"hot spots"to enhance the SERS signal.The detection limits for fipronil,pyrene,anthracene,fluoranthene were 10^-7M?10^-6M?10^-7M and 10^-7M.This kind of SERS substrate is simple,reliable and ease-of-fabrication and has wide application prospect in food safety monitoring.Second,core-shell gold-silver bi-metallic metals—AuNR@Ag were synthesized by wet chemical method and assembled on filter paper which was modified with polyelectrolyte?PSS?.Then this substrate was used for the detection of crystal violet,sunset yellow and amaranth.The lowest detection for these colorants were 10^-11M,10^-9M,and 10^-10M,respectively.The three-dimensional network structure of the filter paper is used to increase the adsorption of the bi-metal nanoparticles to make them randomly arranged.At the same time,the synergy of the gold and silver in the bi-metal nanoparticles enhances the sensitivity of the detection of the analytes.This SERS method is economical,simple,and quick,which can be applied for the detection of colorants.