【摘要】 目的 建立基于单位点调控金衬底的表面增强拉曼光谱(surface-enhanced Raman scattering, SERS)方法,定性和定量检测吡虫啉和矮壮素。方法 利用W单原子调控金纳米颗粒的表面电荷和位点电子结构,测试分析其对不同农药残留分子的SERS灵敏度、定量化的趋势变化。结果 吡虫啉的检出限(limits of detection, LODs)可以从单纯用Au衬底的100 ng/mL降低到10 ng/mL,矮壮素的LODs也可以从200 ng/mL降低到10 ng/mL,单位点增强SERS灵敏度均促使不同农药分子的LODs降低1～2个数量级。同时,经过调控后的金衬底均展示出良好的定量化效果。因此,单位点调控增强SERS性能的方法具有普适性。在机制方面,对比负载单位点前后的样品,测量Zeta电位和模拟局部电场强度,发现经单位点调控的衬底表面电位和电磁场都有较大增强。因此,库伦力增强分子的表面富集和电磁场增强拉曼散射信号,从而提升拉曼检测灵敏度,同时吸附位点的一致性也增强了拉曼数据的稳定性。结论 本研究利用实验与理论证实了单位点调控对SERS检测性能优化是一种非常有效的策略,依据单位点引起的电磁场增强及吸附富集、电荷转移的增强机制,建立“单位点”提升拉曼检测灵敏度和定量化准确度的方法,为单位点调控在该领域的深入研究提供了基础。更多还原

【Abstract】 Objective To establish a surface enhanced Raman spectroscopy(SERS) method on gold substrate based on single-site regulation to qualitatively and quantitatively detect imidacloprid and cycocel. Methods The surface charge and site electronic structure of gold nanoparticles were controlled by W monoatom, the SERS sensitivity and quantitative trend of gold nanoparticles to different pesticide residues were tested and analyzed.Results The limits of detection(LODs) of imidacloprid could be reduced from 100 ng/mL to 10 ng/mL used Au substrate alone, and the LODs of cycocel could also be reduced from 200 ng/mL to 10 ng/mL. The single-site enhanced SERS sensitivity could reduce the LODs of different pesticide molecules by 1-2 orders of magnitude. At the same time,the regulated Au substrates all showed good quantitative effects. Therefore, the method of single-site regulation to enhance SERS performance was universal. In terms of mechanism, compared the samples before and after loading a single-point, measured the Zeta potential and simulating the local electric field strength, it was found that the substrate surface potential and electromagnetic field controlled by a single-site was better. Therefore, the Coulomb force enhanced the surface enrichment of molecules and the electromagnetic field enhanced the Raman scattering signal, thereby improving the Raman detection sensitivity, and the consistency of the adsorption sites also enhanced the stability of the Raman data. Conclusion Experiments and theories have been used to prove that single-site regulation is a very effective strategy for SERS detection performance optimization. According to the enhancement mechanism of electromagnetic field enhancement, adsorption enrichment, and charge transfer caused by single-site, a method for “single-site” to improve Raman detection sensitivity and quantitative accuracy has been established,which provides a basis for further research on unit point regulation in this field.更多还原