An imine-based colorimetric chemodosimeter for the detection of hypochlorite (ClO-) in aqueous media: its application in test strips and real water samples

A highly selective colorimetric chemodosimeter ASAD, (E)-2-((4-(diethylamino)-2-hydroxybenzylidene)amino)-5-methoxybenzenesulfonic acid, was readily synthesized and characterized. The probe ASAD could selectively recognize hypochlorite (ClO-) through an oxidative cleavage of C=N bond with a color change from yellow to colorless and detected it down to a low concentration of 0.95 M. Importantly, ASAD could be employed as a practical and efficient optical sensor for ClO- in test strips and water samples. Moreover, the detection process of ASAD to hypochlorite was demonstrated by UV-vis spectroscopy, NMR titration and theoretical calculations.