Creedon Niamh, Lovera Pierre, Moreno Julio Gutierrez, Nolan Michael, O'Riordan Alan
Nanotechnology Group, Tyndall National Institute, University College Cork, Lee Maltings, Cork T12 R5CP, Ireland.
Materials Modelling for Devices Group, Tyndall National Institute, University College Cork, Lee Maltings, Cork T12 R5CP, Ireland.
J Phys Chem A. 2020 Sep 10;124(36):7238-7247. doi: 10.1021/acs.jpca.0c02832. Epub 2020 Aug 28.
The use of surface enhanced Raman spectroscopy in the development of low cost, portable sensor devices that can be used in the field for nitroguanidine neonicotinoid insecticide detection is appealing. However, a key challenge to achieving this goal is the lack of detailed analysis and vibrational assignment for the most popular neonicotinoids. To make progress toward this goal, this paper presents an analysis of the bulk Raman and SERS spectra of two neonicotinoids, namely clothianidin and imidacloprid. Combined with first-principles simulations, this allowed assignment of all Raman spectral modes for both molecules. To our knowledge, this is the first report of SERS analysis and vibrational assignment of clothianidin, and a comprehensive assignment and analysis is provided for imidacloprid. Silver nanostructured surfaces were fabricated for qualitative SERS analysis, which provides the characteristic spectra of the target molecules and demonstrates the ability of SERS to sense these molecules at concentrations of 1 ng/mL. These concentrations are on par with high-end chromatographic-mass spectroscopy laboratory methods. These SERS sensors thus allow for the selective and sensitive detection of neonicotinoids and provide complementary qualitative data for the molecules. Furthermore, this technique can be adapted to portable devices for remote sensing applications. Further work focuses on integrating our device with an electronics platform for truly portable residue detection.
利用表面增强拉曼光谱开发低成本、便携式传感器设备用于现场检测硝基亚甲基新烟碱类杀虫剂很有吸引力。然而，实现这一目标的关键挑战在于，对于最常见的新烟碱类杀虫剂缺乏详细分析和振动归属。为朝着这一目标取得进展，本文对两种新烟碱类杀虫剂（即噻虫胺和吡虫啉）的体相拉曼光谱和表面增强拉曼光谱进行了分析。结合第一性原理模拟，实现了对这两种分子所有拉曼光谱模式的归属。据我们所知，这是关于噻虫胺表面增强拉曼光谱分析和振动归属的首次报道，并且为吡虫啉提供了全面的归属和分析。制备了银纳米结构表面用于定性表面增强拉曼光谱分析，该分析提供了目标分子的特征光谱，并证明了表面增强拉曼光谱在1 ng/mL浓度下检测这些分子的能力。这些浓度与高端色谱 - 质谱实验室方法相当。因此，这些表面增强拉曼光谱传感器能够选择性且灵敏地检测新烟碱类杀虫剂，并为这些分子提供补充定性数据。此外，该技术可应用于便携式设备以用于遥感应用。进一步的工作重点是将我们的设备与电子平台集成，以实现真正的便携式残留检测。
