Magnetically recoverable fluorescence chemosensor for the adsorption and selective detection of Hg2+ in waterElectronic supplementary information (ESI) available. See DOI: 10.1039/c3em00462g

In order to conveniently and effectively detect the heavy metal ion Hg 2+ existing in water, a magnetic fluorescence chemosensor has been strategically prepared by immobilizing a Rhodamine B derivative RhB-tris(2-aminoethyl)amine on Fe 3 O 4 @SiO 2 -Au@PSiO 2 composites via gold particles. The adsorption and detection for Hg 2+ ions were investigated with fluorophotometry. This chemosensor shows high sensitivity and high selectivity for Hg 2+ over other metal cations owing to the ring opening of the rhodamine fluorophore selectively induced by Hg 2+ . In addition, the presence of Fe 3 O 4 in the sensor also facilitates the magnetic separation of the Fe 3 O 4 @SiO 2 -Au-Hg 2+ @PSiO 2 from the solution. A magnetically recoverable fluorescence chemosensor exhibits high sensitivity, selectivity and regenerability for detection of Hg 2+ ions in water.