Fabrication of Au nanorod-coated Fe3O4 microspheres as SERS substrate for pesticide analysis by near-infrared excitation

• Published in: Journal of Raman spectroscopy 2015-05, Vol.46 (5), p.470-475
• Main Authors: Tang, Xianghu, Dong, Ronglu, Yang, Liangbao, Liu, Jinhuai
• Format: Article
• Language: English
• Subjects: Au nanorods; Fe3O4 microspheres; near-infrared excitation; pesticide analysis; SERS substrate
• ISSN: 0377-0486; 1097-4555
• DOI: 10.1002/jrs.4658

Au nanorods coated Fe3O4 (Fe3O4@NRs) microspheres were designed as functional surface‐enhanced Raman scattering substrate with a feature of magnetic property and used for detection of pesticide residues that are annually used in agriculture by near‐infrared (NIR) excitation. With this strategy, the Fe3O4 microspheres were synthesized by hydrothermal method and surface functionalized with polyethylenimine, and then coated with Au nanorods densely. The Raman spectra were carried out by NIR excitation and 4‐ATP was chosen as the probe molecule. The results showed a good SERS activity of the Fe3O4@NRs microspheres. Moreover, this substrate could be used for pesticide analysis by portable Raman spectrometer with NIR excitation. Especially, the microspheres could be transferred from pesticides contaminated fruits peel to specially cleaned glass slide with the aid of the external magnetic field, by which the strong fluorescence of the apple components can be avoided while performing the pesticide analysis of fruits peel. Copyright © 2015 John Wiley & Sons, Ltd. Au nanorod‐coated Fe3O4 (Fe3O4@NRs) microspheres were designed as functional surface‐enhanced Raman scattering (SERS) substrate with a feature of magnetic property and used for detection of pesticide residues that are annually used in agriculture by near‐infrared (NIR) excitation. With this strategy, the Fe3O4 microspheres were synthesized by hydrothermal method and surface functionalized with polyethylenimine (PEI), and then coated with Au nanorods densely. The Raman spectra were carried out by NIR excitation, and 4‐ATP was chosen as the probe molecule. The results showed a good SERS activity of the Fe3O4@NR microspheres. Moreover, this substrate could be used for pesticide analysis by portable Raman spectrometer with NIR excitation. Especially, the microspheres could be transferred from pesticide‐contaminated fruit peel to specially cleaned glass slide with the aid of the external magnetic field, by which the strong fluorescence of the apple components can be avoided while performing the pesticide analysis of fruit peel.