Conformation Sensitivity And Quantitative Analysis Of Selection Rule For Surface Enhanced Raman Scattering

Because the detection system itself contains more interference components,the detection of analytes in complex systems becomes more difficult.Food matrix and biological fluids are mixed systems containing complex components,and the detection of a certain component often needs to be very complicated.The separation and purification steps,but the complex sample preparation often leads to the loss of the target,and there is a deviation between the measurement result and the actual sample content.Therefore,the detection of complex systems is full of challenges.Food safety and biofluid detection are closely related to human health.However,due to the lack of detection materials and detection strategies,the safety inspections in complex systems are challenging.Therefore,new detection substrates are needed for food matrices and organisms fluid analytes.Based on the advantages of superhydrophobic interface and Surface-enhanced Raman Scatting(SERS)technology,this study developed a superhydrophobic SERS platform that can be used for the enrichment analysis of harmful components in complex systems such as foods and body fluids,and can be used in serum by specific modification of hydrophilic sites.Separation,enrichment,and Raman analysis of dopamine.This thesis including two main parts:(1)The superhydrophobic SERS substrate is successfully prepared by polymer blend lithography and has a uniform microscopic appearance.By specifically decorating PFES,the material obtained excellent hydrophobic properties,the contact angle of the surface droplets is larger than 150°,the bouncing experiment and surface self-cleaning experiment also proved that the materials not only had excellent hydrophobic properties,also had less liquid adhesion,which allowed droplets to condense into the contact area of 0.237 mm2 after the solvent evaporated.The microstructure of the SEM characterization and laser confocal fluorescence imaging confirmed that the deposition site of R6 G was a resonant plasma silver dendrite that provided SERS enhancement on the substrate surface,which was consistent with the directional transport of the analytes.Secondly,by adding 4?L 10-6 M R6 G to the hydrophobic substrate,Raman intensity increased 6.2 times.It is found that Raman enhancement is stronger than that of the liquid sol or solid substrate,which greatly improves the sensitivity of the analysis.The detection sensitivity of 2×10-8 M can be obtained for the detection of R6 G,and the detection of malachite green in fish meat can be successfully performed with the corresponding sample pretreatment.The detection sensitivity can reach 10-7 M.At the same time,the detection and analysis of benzopyrene in edible oil and can be used for trace amounts and micro volumes.Sensitive detection of foreign substances in foods has the universality of detection.(2)SERS detection of dopamine in PBS buffer was successfully achieved by using p-mercaptophenylboronic acid(MPBA)to modify the hydrophilic silver dendritic sites.The maximum change of the detection event was optimized under the condition of p H 8.0 with a detection limit of 2×10-11 mol.Through the Raman spectrum simulation and NPA analysis found that the theoretical simulation results are in good agreement with the spectral changes in the experiment,and the feasibility of the detection is proved theoretically.Further experiments have proved that the selectivity of MPBA to DA can be detected in variety of o-hydroxy compounds disturbance(ascorbic acid,glucose,sucrose,fructose).This platform has been successfully applied to detecting dopamine in human serum,which proves that the material has the superior ability of resisting protein and salt ion interference.(3)The probes designed based on the detection sensitivity of the-O-SO2-group to the mercapto substances group were characterized by the hydrogen spectrum.characterized its chemical structure by hydrogen spectrum and analyzed its interaction with reducing glutathione by HPLC.The results demonstrated its retention time,the successful realization of the probe and reducing glutathione product testing,indicating that the probe design is in line with experimental expectations.