A simple, effective method has been demonstrated to immobilize Rhodamine B (RhB) probes on mesoporous silica (Au-HMS). The prepared chemosensor (Au-HMS-Probe) was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), UV-vis spectrum and Fourier transform infrared spectroscopy (FT-IR). Further application of Au-HMS-Probe in sensing Hg2+ was confirmed by fluorescence titration experiment. Au-HMS-Probe afforded "turn-on" fluorescence enhancement and displayed high brightness in water, and it also showed excellent selectivity for Hg2+ over alkali (Na+, K+), alkaline earth (Mg2+, Ca2+) and other heavy metal ions (Ag+, Cd2+, Co2+, Pb2+, Ni2+, Cu2+, Fe2+). Importantly, Au-HMS-Probe could be regenerated by treatment with tetrapropylammonium hydroxide solution. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.