Nguyen Trang H D, Zhang Zhong, Mustapha Azlin, Li Hao, Lin Mengshi
Food Science Program, Division of Food Systems and Bioengineering, and ‡Department of Mechanical and Aerospace Engineering, University of Missouri , Columbia, Missouri 65211-5160, United States.
J Agric Food Chem. 2014 Oct 29;62(43):10445-51. doi: 10.1021/jf5036417. Epub 2014 Oct 15.
This study aimed to use gold nanorods and graphene as key materials to fabricate high-performance substrates for the detection of pesticides by surface enhanced Raman spectroscopy (SERS). Three types of pesticides (azinphos-methyl, carbaryl, and phosmet) were selected. Gold nanorods have great potential to be used as a SERS substrate because it is easy to tune the surface plasmon resonance of the nanorods to the laser excitation wavelength of Raman spectroscopy. Graphene is a promising nanoscale material that can be used for supporting metal nanostructures. Three types of novel SERS substrates were fabricated, including graphene-gold film-gold nanorod (G-Au-AuNR) substrate, gold film-gold nanorod (Au-AuNR) substrate, and graphene coupled with gold nanorods (G-AuNR). The results demonstrate that G-Au-AuNR substrates exhibited the strongest Raman signals of the selected pesticides, followed by the Au-AuNR substrates. G-AuNR exhibited the weakest Raman signals, and no characteristic spectral features of the analytes were obtained. A partial least-squares method was used to develop quantitative models for the analysis of spectral data (R = 0.94, 0.87, and 0.86 for azinphos-methyl, carbaryl, and phosmet, respectively). The G-Au-AuNRs substrate was able to detect all three types of pesticides at the parts per million level with limits of detection at around 5, 5, and 9 ppm for azinphos-methyl, carbaryl, and phosmet, respectively. These results indicate that combining gold nanorods and graphene has great potential in the fabrication of sensitive, lightweight, and flexible substrates for SERS applications to improve food safety.
本研究旨在使用金纳米棒和石墨烯作为关键材料，通过表面增强拉曼光谱（SERS）制备用于检测农药的高性能基底。选择了三种农药（甲基谷硫磷、西维因和亚胺硫磷）。金纳米棒作为SERS基底具有很大潜力，因为很容易将纳米棒的表面等离子体共振调谐到拉曼光谱的激光激发波长。石墨烯是一种有前景的纳米材料，可用于支撑金属纳米结构。制备了三种新型SERS基底，包括石墨烯-金膜-金纳米棒（G-Au-AuNR）基底、金膜-金纳米棒（Au-AuNR）基底以及石墨烯与金纳米棒耦合（G-AuNR）。结果表明，G-Au-AuNR基底对所选农药表现出最强的拉曼信号，其次是Au-AuNR基底。G-AuNR表现出最弱的拉曼信号，未获得分析物的特征光谱特征。使用偏最小二乘法建立光谱数据定量分析模型（甲基谷硫磷、西维因和亚胺硫磷的R分别为0.94、0.87和0.86）。G-Au-AuNR基底能够在百万分之一水平检测所有三种农药，甲基谷硫磷、西维因和亚胺硫磷的检测限分别约为5、5和9 ppm。这些结果表明，结合金纳米棒和石墨烯在制备用于SERS应用的灵敏、轻质且柔性基底以改善食品安全方面具有巨大潜力。
