A rapid and selective “on–off” fluorescence detection of lethal pulmonary agent phosgene supplemented with theoretical approach: a cost-effective sensing tool for household bleach and soil analysis

Abstract

A fluorescent probe, 4-(di-phenylamino)-benzaldehyde oxime (DPBO), was developed comprising 4-(diphenylamino) benzaldehyde as the fluorophore and hydroxyl amine, where the resultant oxime group leads to the formation of a recognition site for the selective “on–off” fluorescence detection of lethal phosgene with the dimer formation of DPBO through carbonate linkage generated from phosgene. The probe DPBO also exhibits notable spectrofluorometric response in different solvents, as demonstrated by SEM analysis. The detection limit of the probe DPBO towards phosgene was calculated as 21.53 μM, with a fast reaction response time within 30 s and the fluorescence quenching efficiency of DPBO by phosgene was measured through the Stern–Volmer quenching constant (K_SV) estimated at 1.03 × 10⁴ M⁻¹. Confirmation of the sensing mechanism was achieved through various spectroscopic techniques such as UV-vis, emission spectroscopy, mass spectrometry, and computational studies. For practical applications, the sensor DPBO can be utilized for the detection of phosgene in household bleach, soil analysis and dipstick method.