Zhang Zhong, Yu Qingsong, Li Hao, Mustapha Azlin, Lin Mengshi
Food Science Program, Div. of Food Systems & Bioengineering, Univ. of Missouri, Columbia, MO, 6521-5160, U.S.A.
J Food Sci. 2015 Feb;80(2):N450-8. doi: 10.1111/1750-3841.12759. Epub 2015 Jan 20.
There is an increasing interest in recent years in using novel nanomaterials as cost-effective, sensitive, and reproducible substrate for surface-enhanced Raman spectroscopy (SERS) applications. In this study, a novel SERS substrate was developed by assembling gold nanorods into standing arrays on a gold-coated silicon slide. The standing nanorod arrays were closely packed on the gold film, generating strong electromagnetic field and uniformly distributed SERS "hot-spots" on the array surface. The as-prepared SERS substrates were used to detect a widely used pesticide (that is, carbaryl) in acetonitrile-water solution, apple juice, and cabbage. Results demonstrate that the actual concentrations of carbaryl in apple juice and cabbage were linearly correlated with the concentrations predicted by the multiple linear regression models (R > 0.97). The detection limits of carbaryl in apple juice and cabbage were both 2.5 ppm, meeting the maximum residue limits set by US Environmental Protection Agency (EPA). SERS can detect as low as 0.1 ppm of carbaryl in acetonitrile-water solution. In addition, satisfactory recoveries were obtained for carbaryl in both apple juice and cabbage. These results indicate that SERS coupled with the standing gold nanorod array substrates is a sensitive and reproducible method and can accurately detect pesticides in foods.
近年来，人们越来越关注使用新型纳米材料作为表面增强拉曼光谱（SERS）应用中具有成本效益、灵敏且可重复的基底。在本研究中，通过将金纳米棒组装成金涂层硅片上的直立阵列，开发了一种新型SERS基底。直立的纳米棒阵列紧密堆积在金膜上，在阵列表面产生强电磁场和均匀分布的SERS“热点”。所制备的SERS基底用于检测乙腈 - 水溶液、苹果汁和卷心菜中广泛使用的农药（即西维因）。结果表明，苹果汁和卷心菜中西维因的实际浓度与多元线性回归模型预测的浓度呈线性相关（R>0.97）。苹果汁和卷心菜中西维因的检测限均为2.5 ppm，符合美国环境保护局（EPA）设定的最大残留限量。SERS能够检测乙腈 - 水溶液中低至0.1 ppm的西维因。此外，苹果汁和卷心菜中西维因的回收率均令人满意。这些结果表明，SERS与直立金纳米棒阵列基底相结合是一种灵敏且可重复的方法，能够准确检测食品中的农药。
