A simple chromone-derived fluorescent "Turn-on" probe for accurate detection of Al³⁺ Ions: Applications in food Analysis, test strips and bioimaging

To address the toxicity concerns of aluminum ions (Al³⁺) due to their widespread environmental presence, a novel chromone-derived fluorescent probe, (E)-N'-((4-oxo-4H-chromen-3-yl)methylene)benzohydrazide (NMA), was developed for dual-mode detection combining colorimetric and fluorometric channels. Upon chelation with Al³⁺ in a 1:1 stoichiometric ratio, NMA exhibited a significant fluorescence enhancement at 510 nm, accompanied by a rapid and visible color change due to the chelation-enhanced fluorescence (CHEF) effect, achieving an exceptional detection limit of 9 nM-well below the World Health Organization's recommended threshold. The reversible binding of NMA, demonstrated through sequential addition of Al³⁺ and EDTA, enabled the construction of an INHIBIT molecular logic gate, broadening its potential for smart sensing applications. Structural interactions and selectivity were confirmed through ¹H NMR, FT-IR spectroscopy, and density functional theory (DFT) calculations. NMA proved highly effective in diverse applications, including detecting Al³⁺ in food samples, bioimaging in living cells, and environmental monitoring via smartphone-assisted platforms and test strips, making it a powerful tool for addressing aluminum toxicity in practical and real-time settings.