Key Laboratory of Photoelectric Materials and Devices of Zhejiang Province, Ningbo University, Ningbo 315211, China.
Engineering Research Center for Advanced Infrared Photoelectric Materials and Devices of Zhejiang Province, Ningbo University, Ningbo 315211, China.
ACS Appl Mater Interfaces. 2023 Jun 28;15(25):30998-31008. doi: 10.1021/acsami.3c04059. Epub 2023 Jun 16.
Surface-enhanced Raman scattering (SERS) has great potential in the field of rapid detection of pesticide residues in food. In this paper, a fiber optic SERS sensor excited by evanescent waves was proposed for efficient detection of thiram. Silver nanocubes (Ag NCs) were prepared as SERS active substrates, which had much stronger electromagnetic field intensity than nanospheres under laser excitation due to much more "hot spots". By using the method of electrostatic adsorption and laser induction, Ag NCs were uniformly assembled at the fiber taper waist (FTW) for enhancing the Raman signal. Different from the traditional way of stimulation, evanescent wave excitation greatly increased the interaction area between the excitation and analyte, while reducing the damage of the excited light to the metal nanostructures. The methods proposed in this work have been successfully used to detect the pesticide residues of thiram and showed good detection performance. The detection limits for 4-Mercaptobenzoic acid (4-MBA) and thiram were determined to be 10 and 10 M, the corresponding enhancement factor could be 1.64 × 10 and 6.38 × 10. Low concentration of thiram was detected in the peels of tomatoes and cucumbers, indicating its feasibility in actual sample detection. The combination of evanescent waves and SERS provides a new direction for the application of SERS sensors, which had great application potential in the field of pesticide residue detection.
表面增强拉曼散射（SERS）在食品中快速检测农药残留方面具有巨大的潜力。本文提出了一种基于消逝波激发的光纤 SERS 传感器，用于高效检测福美双。银纳米立方体（Ag NCs）被制备为 SERS 活性基底，由于更多的“热点”，在激光激发下，其电磁场强度比纳米球强得多。通过静电吸附和激光诱导的方法，Ag NCs 被均匀地组装在光纤锥腰（FTW）处，以增强拉曼信号。与传统的激发方式不同，消逝波激发大大增加了激发光与分析物之间的相互作用面积，同时减少了激发光对金属纳米结构的损伤。本工作中提出的方法已成功用于检测福美双农药残留，并表现出良好的检测性能。确定了 4-巯基苯甲酸（4-MBA）和福美双的检测限分别为 10 和 10 M，对应的增强因子分别为 1.64×10 和 6.38×10。在番茄和黄瓜的果皮中检测到低浓度的福美双，表明其在实际样品检测中具有可行性。消逝波与 SERS 的结合为 SERS 传感器的应用提供了新的方向，在农药残留检测领域具有巨大的应用潜力。
