LAUSR

A very simple Schiff Base derived from 1-Naphthylamine and 4-(Trifluoromethy) benzaldehyde (L) was prepared as a selective colorimetric and turn-on fluorescent sensor for hydrogen sulfate. In the CH3CN:H2O (3:2, v/v) solvent system, L shows a highly selective colorimetric response to HSO4− ions by changing its color from yellow to colorless immediately. In addition, the weakly fluorescent receptor L shows a highly selective enhancement of fluorescence intensity at 425 nm for HSO4− upon excitation at 320 nm. The recognition process is proven to be hardly influenced by the other tested competitive anions. The sensing is suggested to involve a hydrolysis process promoted by HSO4− which has been further supported by UV–Vis, 1H NMR and HRMS spectroscopic studies. Applicability of L to detect HSO4− in tap water has been demonstrated. An easy-to-prepare test strip of L has also been made for the naked-eye detection of HSO4− in real samples.