A novel quick and highly selective "turn-on" fluorescent probe for Hg2+ and its application

In the present work, we reported the simple synthetic strategy of fluorescent probe BAA. In order to increase the binding ability and selectivity of the probe for Hg2+, an alkynyl group was introduced on the adjacent position of the azo group of the probe. The molecular structure of BAA was characterized by H-1 NMR, C-13 NMR, IR, and MALDI-TOF. Spectrum analysis indicated that BAA exhibited high selective turn-on fluorescence signal and rapid response (about 10 s) to Hg2+. The selectivity can also be visualized under UV light, the BAA shows green fluorescence emission only in the presence of Hg2+. The stoichiometric ratio (1:1) between the probe and Hg2+ could be obtained by the Job-plot and ESI-MS analysis, and was confirmed by quantum chemical calculations. The detection limit of Hg2+ was 1.30 x 10(-7) M in aqueous media. We have demonstrated the suggested probe can detect Hg2+ in lake water samples with satisfying results. Moreover, it exhibits excellent membrane permeability and has been successfully used for detection of Hg2+ in MCF-7 living cells by confocal fluorescence imaging. The explored facile "turn-on" He2+ fluorescent probe here may have the further potential applications in environmental testing, biomedicine and food analysis.