噻菌灵在纳米银胶表面吸附的表面增强拉曼光谱研究

噻菌灵(TBZ)属苯并咪唑类杀菌剂，容易在水果、蔬菜及相应的果蔬饮品中形成有毒残留。基于密度泛函理论(DFT)的量子化学计算方法和表面增强拉曼光谱(SERS)技术，从理论和实验角度系统研究了噻菌灵在纳米银胶粒子表面的吸附行为和增强效应。采用柠檬酸钠还原法制备了具有表面增强拉曼散射活性的银纳米溶胶，并对水相的噻菌灵进行了SERS光谱研究。利用TBZ-Ag₄四种吸附模型对噻菌灵与银纳米溶胶的相互作用进行了理论分析。结合FT-Raman光谱和B3LYP/6-311G(d)理论计算的结果，借助Gaussian View5.0程序的图形化功能，对噻菌灵分子的振动模式、FT-Raman振动光谱和SERS光谱进行了系统的指认。研究结果表明：噻菌灵分子的所有原子在同一平面上，属于Cs对称性;其在银纳米溶胶表面具有十分显著的表面增强拉曼活性;分子中的S原子与银胶粒子发生吸附作用，并通过该分子的长轴方向垂直于银纳米银胶表面;可利用SERS光谱方法对痕量的噻菌灵进行快速检测。为研究噻菌灵的特性以及其快速检测提供了理论和实验依据。

Surface-Enhanced Raman Scattering of Thiabendazole Adsorbed on Silver Nanoparticles

In the present paper, quantum chemistry calculations method based on the density functional theory (DFT) and surface-enhanced Raman scattering (SERS) spectroscopy technique were used to investigate the adsorption behavior and enhancement effect of thiabendazole on the nanometer silver colloid surface systematically from theoretical and experimental perspective. By sodium citrate’s reduction reaction, nanometer silver colloid with has high surface-enhanced Raman scattering activity was prepared. And then the authors studied the surface-enhanced Raman scattering spectroscopy of the thiabendazole in aqueous solution. The authors carried on the detailed quantum chemistry calculations for the interaction between thiabendazole and nanometer silver colloid, using the TBZ-Ag₄ model to get the adsorption properties of thiabendazole molecule on nanometer silver colloid. Combining FT-Raman spectrum with the theoretical calculation results by the B3LYP/6-311G(d) theoretical level, and the visualization of GaussianView5.0 software, the FT-Raman vibration spectrum and the surface-enhanced Raman scattering spectroscopy of thiabendazole molecule were assigned systematically. All the theoretical and experimental results show that all atoms of thiabendazole are in one plane and the point group of thiabendazole is Cs; Thiabendazole has high surface-enhanced Raman scattering activity on nanometer silver colloid surface; the thiabendazole is absorbed on silver colloid particles by S atom, and the long axis of thiabendazole molecule is perpendicular to the nanometer silver colloid surface; the trace concentration of thiabendazole can be detected rapidly and effectively with the surface-enhanced Raman scattering spectroscopy technique. This work provides a theoretical and experimental basis for the study of thiabendazole’s characteristics and its rapid detection.