Highly sensitive turn-on detection of mercury(II) in aqueous solutions and live cells with a chemosensor based on tyrosine.

Herein, we reported a novel fluorescent chemosensor (DY) based on dansyl group and tyrosine by solid phase peptide synthesis (SPPS) for the detection of mercury(II) ions with excellent selectivity among 17 different metal ions. As designed, DY exhibited a sensitive fluorescence "turn-on" response to Hg2+ with low detection limits of 22.65 nM. A stoichiometric ratio (2: 1) of chemosensor DY and Hg2+ ions was determined by a Job's plot, fluorescent titration and the ESI-MS spectra. Especially, the reversible of DY-Hg with EDTA establishes the reuse of DY, and the circulation effect was very good. Furthermore, the wide pH range of 6-10 makes it capable of application in biological systems. Moreover, DY has been successfully applied to the detection of Hg2+ ions and EDTA in living HeLa and HK2 cells based on low cytotoxicity and good membrane permeability.