Functionalized mesoporous silica as a fluorescence sensor for selective detection of Hg in aqueous medium.

We combined the virtues of mesoporous silica and organic functional groups to develop a hybrid fluorescent sensor, PyU-SBA-15, with excellent ability to detect Hg in aqueous medium with high selectivity. In this sensor, the pyrene fluorophore acts as the reporter and the urea unit acts as the receptor during Hg determination. The control material, PyH-SBA-15, which lacks a carbonyl group in the receptor portion, did not display metal-ion selectivity, thereby demonstrating that introducing an additional metal-chelating unit is necessary to improve the metal-ion selectivity of the hybrid sensor. When the concentration of Hg was increased, the fluorescence emission intensities of PyU-SBA-15 at 379, 398, and 476 nm gradually decreased. The emission intensity at 379 nm was linearly proportional to Hg concentrations in the range of 0-1.0 × 10 M, and the sensor was determined to have a detection limit of 9.92 × 10 M. This work provides an effective strategy for improving or modulating the metal-ion selectivity of fluorescent sensors based on organic-inorganic hybrid mesoporous silica systems.