2-Hydroxynaphthalene based acylhydrazone as a turn-on fluorescent chemosensor for Al³⁺ detection and its real sample...

Developing high performance fluorescent chemosensor for Al³⁺ detection is highly desirable, due to the excess of Al³⁺ will lead to many diseases. In this paper, a simple 2-hydroxynaphthalene-based fluorescent chemosensor has been synthesized and characterized by different spectroscopic methods. The compound exhibited an "turn-on-type" fluorescent chemosensing for the detection of Al³⁺, which was ascribed to the chelation-enhanced fluorescence (CHEF). The high selectivity and sensitivity of the compound for Al³⁺ were verified by fluorescence spectra in its DMF solution, and the enhancement of fluorescent intensity could be observed by naked-eye from non-fluorescence to green light. The detection limit of the compound for Al³⁺ was found to be 4.22 × 10^-8 M and the stability constant was 4.82 × 10⁴ M^-1. The 1:1 binding stoichiometry of the compound to Al³⁺ was confirmed from the Job's plot based on fluorescence titrations. Additionally, the sensing process of the compound to Al³⁺ was chemically reversible by adding Na₂EDTA. Importantly, the probe was successfully applied to quantitative analysis of Al³⁺ in real drug and potable water samples.