Design of a sustainable light-up flavonol probe for dual-ratiometric fluorescent sensing and visual differentiating ammonia and hydrazine.

Ammonia (NH) and hydrazine (NH) present potential risks to human health, food and environmental safety. A sustainable flavonol-based probe, quercetin pentaacetate (QPA, weak blue emission 417 nm), was fabricated for dual-ratiometric fluorescent sensing and visual differentiating NH and NH. Excited state intramolecular proton transfer-on products with green (487 nm) and yellow (543 nm) emissions occurred as meeting with NH and NH, respectively, for their different nucleophilicities. Such a promising response offered a great opportunity of QPA to discriminatively detect NH and NH with large Stokes shifts (>122 nm), high sensitivity (limit of detection: 35.4 μM and 0.70 ppm for NH solution and gas; 0.26 μM for NH solution), excellent accuracy (spiked recoveries from 98.6 % to 105 %), and superior selectivity. Importantly, QPA was utilized for monitoring NH vapor in fish spoilage procedures and detecting NH in water samples for food and environmental safety evaluation.