A highly selective turn-on chemosensor capable of monitoring Zn2+ concentrations in living cells and aqueous solution

A new simple “off-on fluorescence type” chemosensor 1 (2-(N-(2-hydroxyethyl)-N-((pyridin-2-yl)methyl)amino)-N-(quinolin-8-yl)acetamide) has been synthesized for Zn2+. The sensor 1 comprises of the quinoline as fluorophore and the 2-((pyridin-2-yl)methylamino)ethanol as both binding site and water-soluble functional group. 1 showed a remarkable fluorescence enhancement in the presence of Zn2+ in aqueous solution, which was reversible with the addition of ethylenediaminetetraacetic acid (EDTA). The detection limit (0.02 μM) of 1 for Zn2+ is far lower than World Health Organization guideline (76 μM) in drinking water. Importantly, the chemosensor 1 could be used to detect and quantify Zn2+ in living cells and water samples. Moreover, the sensing mechanism was supported by theoretical calculations. Therefore, this sensor has the ability to be a practical system for monitoring Zn2+ concentrations in biological and aqueous samples.