Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei 230031, China.
Nanoscale. 2013 Nov 21;5(22):11193-9. doi: 10.1039/c3nr03671e. Epub 2013 Oct 1.
Here, Au nanoparticles (NPs) grafted on dendritic α-Fe2O3 (NPGDF) are designed as a highly uniform surface-enhanced Raman scattering (SERS) substrate with a feature of optical visualization by an optical microscope (OM) system and used for in situ detection of pesticide residues that are annually used in agriculture. With this strategy, the dendritic α-Fe2O3 has been synthesized by a hydrothermal method and significantly functionalized by an inductively coupled plasma (ICP) apparatus and then Au NPs were grafted on it densely and uniformly. In addition, the profile of NPGDF can be clearly observed using an OM platform of a Raman spectrometer, and the profile of SERS spectral mapping with NPGDF as substrate almost exactly coincides with the OM image, the electron microscope (EM) image and the elemental mapping of NPGDF, which indicates remarkable uniformity of the NPGDF as SERS substrate, thus ensuring the laser beam focuses on the efficient sites of the substrate under the OM platform. Moreover, NPGDF can be dispersed in the liquor and the NPGDF microparticles can be adsorbed on the target surface. Therefore, it can be used for in situ detection of pesticide residues on tea leaves, fruits etc., with high sensitivity and reproducibility.
在这里，设计了负载在树枝状α-Fe2O3（NPGDF）上的金纳米粒子（Au NPs）作为具有光学可视化功能的高度均匀的表面增强拉曼散射（SERS）基底，通过光学显微镜（OM）系统进行观察，用于原位检测农业中每年使用的农药残留。通过这种策略，树枝状α-Fe2O3 通过水热法合成，并通过感应耦合等离子体（ICP）设备进行显著功能化，然后Au NPs 被密集且均匀地接枝在其上。此外，NPGDF 的形貌可以在拉曼光谱仪的 OM 平台上清晰地观察到，并且使用 NPGDF 作为基底的 SERS 光谱映射的形貌几乎与 OM 图像、电子显微镜（EM）图像和 NPGDF 的元素映射完全吻合，这表明 NPGDF 作为 SERS 基底具有显著的均匀性，从而确保在 OM 平台下激光束聚焦在基底的有效部位。此外，NPGDF 可以分散在液体中，并且 NPGDF 微粒可以被吸附在目标表面上。因此，它可以用于原位检测茶叶、水果等表面的农药残留，具有高灵敏度和重现性。
