A recyclable diacylhydrazone-based turn-on fluorescent chemosensor for detecting Al³⁺ and its practical applications

A novel diacylhydrazone-based fluorescent sensor HMPD was developed for the sensing of Al³⁺. In the presence of Al³⁺, HMPD showed a marked fluorescence increment with a 1:2 stoichiometry of HMPD to Al³⁺. Detection limit of HMPD to Al³⁺ was found as 0.76 μM. HMPD could determine Al³⁺ irrespective of the presence of Ga³⁺ and In³⁺. HMPD was satisfactorily applied to the qualification of Al³⁺ in real water samples and test strips. The sensing process of HMPD to Al³⁺ was reversible by EDTA application. Binding process of HMPD to Al³⁺ was proposed through fluorescence and UV–vis spectroscopy, Job plot, FT-IR spectroscopy, ESI-MS, ¹H NMR titration and theoretical calculations.