Water-ratio directed selective turn-on fluorescence detection of copper and mercury in acetonitrile

Abstract

The development of novel sensor probes to sensitively and selectively detect more than one target ion in a given condition is a challenging duty due to the deficiency of effective design strategies. In this study, we report utilizing the water-ratio-directed properties of a TPE-TSC-based turn-on fluorescent selective detection of multiple ions by using acetonitrile and acetonitrile-water. When pure acetonitrile was used as the solvent, TPE-TSC was not showed a selective and sensitive effect for any ions. Thereupon, studies were carried out in aqueous solutions of acetonitrile. As a result of studies, TPE-TSC was showed a selective and sensitive fluorescence “turn on” response towards Cu2+ and Hg2+ in CH3CN/H2O (30–50% of water for Cu2+, 70–90% of water for Hg2+). When an aqueous solution of acetonitrile (CH3CN/H2O; v/v:1/1) was used, the TPE-TSC was determined to be a sensitive and selective fluorescent “turn on” sensing for Cu2+ with a LOD value of 15.74 µM, which is the range of copper that should be in the blood (11.8–23.6 μM). In addition, when the studies were carried out in CH3CN/H2O (v/v:1/9), TPE-TSC was further determined to be a turn-on fluorescent sensing for Hg2+ with a LOD value of 18 µM. Moreover, DFT calculations confirmed the nonplanar or propeller structures. As a result of all these studies, it can be said that TPE-TSC, may be a useful and water-ratio-directed selective turn-on sensor candidate for Cu2+ and Hg2+ sensing in industrial wastewaters.