Construction Of Novel MOF-based SERS Substrate And Its Application In Detection Of Sulfur Dioxide And Chiral Molecules

Surface Enhanced Raman Scattering(SERS)is a typical non-destructive analysis technique,which has been rapidly developed in chemical and biological analysis.SERS technology has broad application prospects in the fields of biology,food safety,environmental assessment and medicine.However,the application of SERS technology largely depends on the use of the substrate.At present,the preparation of a multifunctional and highly sensitive SERS substrate is one of the main research hotspots in SERS analysis,so that it can specifically bind to the target molecule.Based on this,this thesis is mainly based on silver nanomaterials and metal-organic framework(MOF).Two different types of nanocomposite materials are designed as SERS substrates to study the application of sulfur dioxide and chiral molecule analysis and detection.The main conclusions were as follows:(1)Preparation of NU-901@AMPM-Ag base material and its application in SO₂detection.In this chapter,we constructed a new core-shell nanocomposite(NU-901@AMPM-Ag)as a SERS substrate for the qualitative and quantitative detection of SO₂ in the colorimetric/Raman dual sensing mode.Mainly based on the condensation reaction of amino and carboxyl groups,AMPM-specific probe molecules were prepared,which can specifically bind to SO₂.The probe molecule AMPM was modified on the surface of Ag NPs through the Ag-S bond through the ligand exchange program to prepare AMPM-Ag NPs.Finally,through self-assembly with MOF(NU-901),a new core-shell nanocomposite material(NU-901@AMPM-Ag)was constructed,and the material was deposited on a paper sheet by a simple suction filtration method to prepare NU-901@AMPM-Ag NPs substrate.The core-shell nanocomposite NU-901@AMPM-Ag combines sufficient Raman"hot spots"in high-density Ag NPs and excellent adsorption properties of MOF,making it an excellent SERS substrate for selective and sensitive detection and analysis Things.AMPM-Ag NPs probe molecules can specifically bind to SO₂,and we can observe the obvious change of color with the naked eye.(2)Preparation of MIL-101@Ag-GSH substrate material and its application in the detection of chiral molecules.In this chapter,we successfully prepared the MIL-101@Ag-GSH nanocomposite as a SERS substrate,in which GSH as a probe molecule can specifically bind to cysteine of different configurations.The SERS technology realizes the effect of D-Cys and Identification of L-Cys.Firstly,Ag NPs@MIL-101 hybrid materials were prepared by in-situ synthesis,and then the probe molecule GSH was modified on the Ag NPs@MIL-101 surface through the Ag-S bond through the ligand exchange program.The MIL-101@Ag-GSH composite material was prepared,and an efficient SERS substrate was developed.MIL-101@Ag-GSH as a SERS substrate exhibits high selectivity,reproducibility and stability.The substrate combines the numerous Raman hotspots between high-density silver nanoparticles and the excellent adsorption performance of porous materials.It can effectively concentrate the analytes near the Raman hotspots between adjacent silver nanoparticles,making it Excellent SERS substrate for high sensitivity SERS detection.The SERS substrate has a good application prospect in the identification and detection of chiral molecules,and may open up new opportunities for chemical and biological analysis applications.