Real-time probing of mercury using an efficient “turn-on” strategy with potential as in-field mapping kit and in live cell imaging†
Abstract
Based on a rhodamine scaffold as a fluorophore and 2-aminothiazole as a receptor, we present a highly selective and sensitive sensor (TS). An enhanced photophysical response (fluorescence as well as absorption) accompanied by high sensitivity and selectivity was observed upon interaction of TS with Hg2+ among various competitive cations (Ag+, Al3+, Ba2+, Ca2+, Co3+, Co2+, Cd2+, Fe3+, Fe2+, K+, Li+, Mg2+, Mn2+, Cu2+, Pb2+, Ni2+, Na+ and Zn2+) in CH3CN : H2O (7 : 3 v/v, HEPES buffer 10 mM pH 7.0). The synthesized sensor can detect Hg2+ as low as 0.326 μM with a complexation constant of 2.37 × 106 M−1. This complexation between TS and Hg2+ is reversible in the presence of ethylenediaminetetraacetate (EDTA). Furthermore, single crystal X-ray diffraction (XRD) and Job's plot results show a 1 : 1 binding stoichiometry. The most interesting feature of the sensor is the real-time determination of Hg2+ in real contaminated water. Furthermore, the fabricated sensor can be employed as an intracellular monitoring agent for live cell imaging of the HeLa cell line.