A novel coumarin-derived dithioacetal chemosensor for trace detection of Hg2+ in real water samples

A novel coumarin-derived dithioacetal chemosensor, 8-(1,3-dithian-2-yl)-7-hydroxy-4-methylcoumarin (LS), has been designed and synthesized. The sensor LS showed highly selective fluorescent sensing for Hg2+ with a low detection limit of 0.81 nM in the pH range from 6.15 to 9.96 in ethanol/water (1:1, v/v) solution. The sensing mechanism of LS toward Hg2+ was proposed and verified by 1H nuclear magnetic resonance spectroscopy studies. Under an ultraviolet lamp, the fluorescence color changes could be easily detected by the naked eye. In addition, the sensor LS has been applied in the trace detection of Hg2+ in real water samples.