Highly Sensitive Dansyl-Based Chemosensor for Detection of Cu(2+) in Aqueous Solution and Zebrafish

[Image: see text] A new dansyl-based chemosensor (2-(4-((5-(dimethylamino)naphthalen-1-yl)sulfonyl)piperazin-1-yl)-N-(quinolin-8-yl)acetamide) (DC) for detecting Cu(2+) was synthesized and characterized. DC showed great selectivity to Cu(2+) by a fluorescent “on–off” detection method. Job plot, ESI-mass spectroscopy, and (1)H NMR titration suggested a 1 to 1 binding mode between DC and Cu(2+). The detection limit was determined to be 43 nM, which is greatly below the WHO guidelines. In addition, DC can be applied to real samples and zebrafish imaging. The fluorescence quenching mechanism was proposed as the enhancement of intramolecular charge transfer with calculations.