An imine-based colorimetric chemodosimeter for the detection of hypochlorite $\left({\text{ClO}}^{-}\right)$ 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 $\left({\text{ClO}}^{-}\right)$ 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 $\mu \text{M}$. Importantly, ASAD could be employed as a practical and efficient optical sensor for ${\text{ClO}}^{-}$ 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.

Graphical abstract

A highly selective colorimetric chemodosimeter ASAD was developed to selectively recognize hypochlorite $\left({\text{ClO}}^{-}\right)$ through an oxidative cleavage of C=N bond with color change from yellow to colorless and could detect it down to a low concentration of 0.95 $\mu \text{M}$. .