Functionalized magnetic core-shell Fe3O4@SiO2 nanoparticles as selectivity-enhanced chemosensor for Hg(II)

A colorimetric and turn-on fluorescent chemosensor Rho-Fe3O4@SiO2 for Hg2+ in which N-(rhodamine-6G)lactam-ethylenediamine (Rho-en) is conjugated with the magnetic core shell Fe3O4@SiO2 NPs has been strategically designed and synthesized. The final product was characterized by X-ray power diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectra (FTIR) and UV-visible absorption and fluorescence emission. Fluorescence and UV-visible spectra results showed that the resultant multifunctional nanoparticles Rho-Fe3O4@SiO2 exhibited selective 'turn-on' type fluorescent enhancements and distinct color changes with Hg2+. The selectivity of the Rho-Fe3O4@SiO2 for Hg(II) ion is better than that of the Rho-en in the same conditions. In addition, the presence of magnetic Fe3O4 nanoparticles in the sensor Rho-Fe3O4@SiO2 NPs would also facilitate the magnetic separation of the Hg(11) Rho-Fe3O4@SiO2 from the solution. (C) 2011 Elsevier Ltd. All rights reserved.