Ag/Fe3O4 magnetic surface enhanced Raman scattering (SERS) composite material and preparation method and application thereof

The invention relates to an Ag/Fe3O4 magnetic surface enhanced Raman scattering (SERS) composite material and a preparation method and application thereof. The SERS composite material is provided with a colloidal membrane wrapping Ag nanoparticles, formed through self-assembly of Fe3O4 nanoparticles and/or a structure of the colloidal membrane to which the Ag nanoparticles are attached, wherein the grain sizes of the Fe3O4 nanoparticles are 1-10 nanometers, and the sizes of the Ag particles are 5-100 nanometers. The invention initially proposes a technical solution scheme of on-line sewage monitoring for magnetic control by using a magnetic SERS substrate. Compared with other on-line monitoring devices, the real-time and on-line monitoring device applying the Ag/Fe3O4 magnetic SERS composite material, provided by the invention, has the following advantages of SERS detection advantages, namely, high efficiency, rapidness, lossless, high sensitivity and the like, the device is simple and is easy to operate, is