Journal of Hazardous Materials, Vol.287, 402-411, 2015
A metal-enhanced fluorescence sensing platform based on new mercapto rhodamine derivatives for reversible Hg2+ detection
A new metal-enhanced fluorescence (MEF) chemosensor HMS-Ag-R-2SH for Hg2+ has been prepared via a simple and effective method. The fluorescent chemosensor was based on a mercapto rhodamine derivatives linked with Ag nanoparticles, and the Ag nanoparticles were supported on hexagonal mesoporous silica material (HMS). Transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), absorption spectroscopy and fluorescence spectroscopy techniques were employed to characterize morphology, mesostructure and spectral features of the chemosensor. This chemosensor works in a nearly pure aqueous solution with a broad pH range. The output signals include color change and fluorescence. Moreover, HMS-Ag-R-2SH presents excellent anti-disturbance ability when exposed to a series of competitive cations such as Ag+, K+, Li+, Na+, Ba2+, Ca2+, Cd2+, Co2+, Cu2+, Mg2+, Mn2+, Ni2+, Pb2+, Zn2+, Al3+, Cr3+ and Fe3+. The selectivity of this chemosensor was significantly improved due to the introduction of the sulphydryl. The chemosensor showed a lower detection limit of 2.1 ppb for Hg2+. Importantly, HMS-Ag-R-2SH could be regenerated with sodium sulfide solution for several cycles and maintain a high sensitivity. (C) 2015 Elsevier B.V. All rights reserved.