Graphene oxide embedded sandwich nanostructures for enhanced Raman readout and their applications in pesticide monitoring
Graphene oxide embedded sandwich nanostructures for enhanced Raman readout and their applications in pesticide monitoring
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用于增强拉曼读数的氧化石墨烯嵌入夹层纳米结构及其在农药监测中的应用
DOI：
10.1039/c3nr00631j
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发表时间：
2013-01-01
期刊：
影响因子：
6.7
通讯作者：
Zhang, Zhongping
中科院分区：
文献类型：
--
作者：
Zhang, Lulu;Jiang, Changlong;Zhang, Zhongping
基于表面增强拉曼散射(SERS)的分析技术缺乏重复性和可靠性，从而阻碍了其实际应用。在这里，我们开发了一种基于石墨烯氧化物夹心纳米结构的SERS活性衬底，用于超灵敏的拉曼信号读出。通过使用这种新型的Au@Ag NPs/GO/Au@Ag NPs三明治纳米结构作为SERS衬底，由于分析物表面有大量的热点和石墨烯氧化膜的独特结构，分析物的拉曼信号显著增强。这些特点使三明治纳米结构薄膜成为提高拉曼读出灵敏度、重复性和可靠性的理想SERS衬底。该夹心纳米结构膜可用于检测罗丹明-6G(R6G)和市售葡萄汁中农药福美双，其增强因子(EF)接近7.0×10(7)，检出限为0.1亩M(0.03ppm)，远低于美国环境保护局(EPA)规定的水果中7ppm的最大残留限量。GO嵌入的三明治纳米结构还具有选择性地检测二硫代氨基甲酸盐化合物的能力，而不是其他类型的农用化学品。此外，添加测试表明，三明治纳米结构可以用于监测天然湖水和商业葡萄汁中的福美双，而无需进一步处理。此外，GO增强拉曼光谱技术为农产品和环境中农药残留的现场监测和评估提供了潜在的实际应用。
Analytical techniques based on surface-enhanced Raman scattering (SERS) suffer from a lack of reproducibility and reliability, thus hampering their practical applications. Herein, we have developed a SERS-active substrate based on a graphene oxide embedded sandwich nanostructure for ultrasensitive Raman signal readout. By using this novel Au@Ag NPs/GO/Au@Ag NPs sandwich nanostructure as a SERS substrate, the Raman signals of analytes were dramatically enhanced due to having plenty of hot spots on their surfaces and the unique structure of the graphene oxide sheets. These features make the sandwich nanostructured film an ideal SERS substrate to improve the sensitivity, reproducibility and reliability of the Raman readout. The sandwich nanostructure film can be applied to detect rhodamine-6G (R6G) with an enhancement factor (EF) of similar to 7.0 x 10(7) and the pesticide thiram in commercial grape juice with a detection limit of as low as 0.1 mu M (0.03 ppm), which is much lower than the maximal residue limit (MRL) of 7 ppm in fruit prescribed by the U. S. Environmental Protection Agency (EPA). The GO embedded sandwich nanostructure also has the ability to selectively detect dithiocarbamate compounds over other types of agricultural chemical. Furthermore, spiked tests show that the sandwich nanostructure can be used to monitor thiram in natural lake water and commercial grape juice without further treatment. In addition, the GO enhanced Raman spectroscopic technique offers potential practical applications for the on-site monitoring and assessment of pesticide residues in agricultural products and environments.