Determination of Zinc Ion by a Quinoline-Based Fluorescence Chemosensor

A novel fluorescence chemosensor XYQ for detecting Zn(II) was synthesized. XYQ showed fluorescence turn-on to Zn(II) with high sensitivity and selectivity in aqueous media among 19 metal ions. Its binding structure was demonstrated by ESI-MS, Job plot, and ¹H NMR titration. The detection limit of XYQ to Zn(II) was 0.53 μM. It is much below WHO drinking water standard (76.0 μM). XYQ could be applied successfully to the test kit and real samples. The fluorescence turn-on process was possibly explained as a chelation-enhanced fluorescence (CHEF) effect with theoretical calculations.