Facile Synthesis of Fe3O4@Au Core-shell Nanocomposites as an SERS Substrate for the Detection of Thiram

Fe3O4 nanomaterial was prepared by thermal decomposition method, and then Fe3O4-Au core-satellite nanocomposites and Fe3O4@Au core-shell nanocomposites were prepared by seed deposition method and seed-mediated growth method, respectively. The morphology of the Fe3O4-Au core-satellite nanocomposites and Fe3O4@Au core-shell nanocomposites were uniform and the Au nanoparticles were uniformly deposited/coated on the surface of Fe3O4 nanomaterials. The samples had good magnetic responsiveness. Using 4-aminothiophenol (4-ATP) as Raman probe molecule, the Raman signal enhancement effect of the two nanocomposites as SERS substrates was compared. The results showed that the Fe3O4@Au core-shell nanocomposite was a better SERS substrate, and had good signal reproducibility. Finally, using Fe3O4@Au core-shell nanocomposite as SERS substrate, the SERS signal of the residual thiram was detected on the apple peel successfully.