Ag@Fe3O4 Core-Shell Surface-Enhanced Raman Scattering Probe for Trace Arsenate Detection.

Developing an effective and reliable method for trace arsenic (As) detection is a prerequisite for improving the safety of drinking water. In this paper, we designed and prepared Ag@Fe3O4 core-shell nanoparticles (NPs), which were then used as Surface-Enhanced Raman Scattering (SERS) probe for trace arsenate (As(V)) detection. The Ag@Fe3O4 core-shell NPs were prepared by in situ growth of Fe3O4 NPs on the surface of AgNPs, which can effectively combine the strong adsorption ability of Fe3O4 nanoshells to As(V) with high SERS activity of Ag nanocores to decrease the detection limit. By use of Ag@Fe3O4 core-shell NPs for As(V) detection, the detection limit can be as low as 10 μg/L, and a good linear relationship between the SERS intensity of As(V) and their concentrations in the range from 10 to 500 μg/L was achieved. Furthermore, Ag@Fe3O4 core-shell NPs could be regenerated through desorption of As(V) from Fe3O4 nanoshells in NaOH solution, and then used for recyclic SERS detection. Therefore, it has been demonstrated for the first time that multifunctional Ag@Fe3O4 core-shell SERS probe could be applied to realize the highly sensitive and reversible detection of As(V).