Surface-enhanced Raman Spectroscopy Based On Oxide Substrates And Its Applications

Surface-enhanced Raman spectroscopy（SERS）technology plays an important role in the field of new detection techniques with the unique advantages of high sensitivity,high recognition capability and low sample consumption.The core of SERS technology is to design and synthesize substrate materials with good enhancement effect,and among the research on developing new SERS substrates,oxide composite SERS substrates are a popular direction.Synthesis of oxide SERS substrates with good enhancement performance and wide range of applications has great research significance.In this thesis,composite SERS substrates with function of enriching analyte molecules were synthesized based on three oxide materials.Based on surface-enhanced Raman spectroscopy（SERS）technique,quantified determination of sodium thiocyanate,sulfadiazine and ciprofloxacin was performed.1.The Al₂O₃@Agcomposite SERS substrate with flower-like rough surface is developed,and the dense protrusions on its surface and the interstices between the protrusions generate a large number of SERS hot spots bringing strong SERS enhancement.At the same time,with strong adsorption ability,γ-Al₂O₃ can effectively enrich the sodium thiocyanate molecules.The limit of detection（LOD）of sodium thiocyanate was 0.5μg/L.2.The Fe₃O₄/PEI/AgNPs magnetic composite SERS substrate was synthesized based on the principle of electrostatic interaction.The thin PEI layer could adsorb sulfadiazine molecules and further enrich the analytes under the magnetic field,which greatly enhanced the SERS enhancement effect.The limits of detection（LOD）of sulfadiazine in water and lake water were1.48μg/L and 7.31μg/L,respectively.3.The TiO₂/MIL-101（Fe）composite structure was developed by the one-pot method.TiO₂accelerated the formation of the framework structure,bringing more complete ortho-octahedral morphology.The large porosity of TiO₂/MIL-101（Fe）brought the ability to enrich the analyte molecules and made it an ideal backbone for loading AgNPs.The TiO₂/MIL-101（Fe）/AgNPs composite SERS substrates were obtained after silver modification,acquiring strong Raman enhancement of ciprofloxacin.The limit of detection（LOD）of ciprofloxacin in water was obtained as 0.02μM.The quantitative SERS assay for sodium thiocyanate,sulfadiazine and ciprofloxacin based on three oxide composite SERS substrates was established with high sensitivity.It expands the application of oxide materials within the field of SERS and provides technical support for the development of novel SERS substrates.