A highly selective and sensitive fluorescent chemosensor for mercury ions based on the mechanism of supramolecular self-assembly

In this work, a highly sensitive and selective mercury fluorescent sensor (E)-1-((5-(4-nitrophenyl)furan-2-yl)methylene) semicarbazone (BI) based on the 5-(4-nitrophenyl)-2-furan and semicarbazide groups was designed, prepared and utilized to monitor mercury ions in aqueous solution. Upon addition of mercury to BI in DMSO/H2O (8:2, v/v) HEPES buffer (pH = 7.2) solution, an observable decrease of fluorescent to dim red change occurs that can be monitored by using fluorescence spectroscopy at room temperature. Concomitantly, a remarkably reducing in the emission maximum of BI takes place from 580 (a.u.) to 300 (a.u.). The observations indicate that association of the chemosensor with mercury ions leads to the supramolecular self-assembly breaking and the cooperation reaction occurrence, intra molecular charge density decreased in the chemosensor, the phenomenon likely responsible for the large decrease observed in emission spectra. And the detection limit of BI for the determination of mercury was estimated to be 2.084 x 10(-9) M. Notably, this sensor serves as a recyclable component in sensing materials. The experiment proved that this sensor can be repeated use above 10 times. Therefore, the chemosensor has good application prospect for recognizing and detecting Hg2+ in the environment. (C) 2014 Elsevier B.V. All rights reserved.