Preparation of multi-functional magnetic-plasmonic nanocomposite for adsorption and detection of thiram using SERS.

Magnetic materials have been widely used for constructing substrate in surface enhanced Raman scattering (SERS) sensing due to the magnetic responsibility. Here, we reported a facile and effective approach to construct multi-functional SERS substrate based on assembling Ag nanoparticles (NPs) on porous Fe microspheres. The porous Fe microspheres were prepared through hydrogen reduction of Fe2O3 NPs with porous structure, in which the size and morphology of Fe could be well controlled. The surface of Fe was grafted with amino group, and then decorated with Ag NPs. The surface area and pore size of Fe microsphere were characterized by nitrogen adsorption and desorption. The Fe@Ag nanocomposite illustrated a good SERS activity. Furthermore, this substrate could be used for pesticide monitoring by portable Raman spectrometer. Especially, the porous Fe microsphere could adsorb analyte from target sample and the Fe@Ag could be concentrated by magnetic force to amplify the SERS signal for thiram detection.