Fabrication Of Novel SERS Nanoprobes And Its Application For The Detection Of Heavy Metal Ions And Chiral Substances

Heavy metal ions and chiral substances with different configurations have huge hidden dangers to the environment and human health.Therefore,it is of great significance to carry out research on the rapid detection and identification of heavy metal ions and chiral substances.Surface-enhanced Raman scattering(SERS)is a surface analysis technology based on the localized plasmon resonance effect of nanomaterials.It has been widely used in many fields such as biomedicine,environmental monitoring,chemical analysis and food safety testing.However,traditional SERS substrates have weak affinity for heavy metal ions and chiral substances and poor discrimination.Therefore,it is difficult to directly analyze heavy metal ions and chiral substances using SERS technology.Based on this,this thesis designed two new SERS nanoprobes and applied them to the detection of heavy metal ions and chiral substances.The main research contents are as follows:(1)Colorimetric/SERS dual sensing detection of Cu²⁺using Ag-Au core-satellite structure.This chapter successfully constructed an Ag-Au nuclear-satellite nanostructure system to detect Cu²⁺in water.Firstly,4-mercaptobenzoic acid(MBA)modifies silver nanoparticles(Ag NPs)through metal-sulfur bonds to obtain Ag NPs@MBA,and4-mercaptopyridine(Mpy)modifies gold nanoparticles(Au NPs)through metal-sulfur bonds to obtain GNPs@Mpy.Then mix them to get the Ag NPs-GNPs(Ag NPs@MBA-GNPs@Mpy)structure.Triggering this system by Cu²⁺leads to self-aggregation of NPs,and the Ag NPs-GNPs structure becomes Ag NPs-Cu²⁺-GNPs nuclear-satellite nanostructure.Because the pyridyl nitrogen and the carboxyl oxygen have specific coordination ability to Cu²⁺,a certain amount of NP aggregates,which can be easily captured by SERS analysis.Similarly,it can also be clearly recognized by vision.The colorimetric detection limit of the constructed base material for Cu²⁺is 0.032?M,and the detection limit of the SERS method is as low as0.6 p M.It is significantly lower than the 20?M limit set by the US EPA for Cu²⁺in drinking water.In addition,the constructed base material can be successfully used to determine Cu²⁺in various actual water samples and soil samples through the colorimetric method and the SERS dual-sensor analysis method.This work provides a new analytical method for the detection of copper ions in environmental samples,and provides potential application value for the development and field detection of plasma nanostructures.(2)Differentiate and detect chiral 2-chloropropionic acid based on the peak split-assisted SERS technology.This chapter designs and develops a SERS analysis method that combines peak splitting technology to distinguish and detect chiral pesticide intermediate2-chloropropionic acid(2-CPA).In this method,functionalized gold nanorods(GNRs@MPBA)are formed by modifying 4-mercaptophenylboronic acid(4-MPBA)small molecules with Raman signals through Au-S bonds on gold nanorods(GNRs).And introduce chiral glucose to this material to form chiral nanomaterials.The constructed chiral nanomaterials recognize chiral 2-chloropropionic acid through hydrogen bonding.The irregular shape of the gold nanorods can effectively concentrate the analyte in the nearby hot spots between adjacent gold nanorods.Make it a base material with high SERS activity.In addition,combined with the method of peak splitting to amplify the difference,2-chloropropionic acid was quantitatively analyzed.The peak splitting assisted SERS technology ensures the sensitivity and accuracy of the detection of chiral substances,and provides a new simple analytical method strategy for the identification and detection of chiral substances.It provides potential application value for the development of new and efficient chiral sensors and for in-depth understanding of the enantioselective behavior of organic enantiomers on the surface of inorganic nanomaterials.