In this study, a siderophore, pyoverdine (PVD), has been isolated from Pseudomonas sp. and used to develop a fluorescence quenching-based sensor for efficient detection of nitrotriazolone (NTO) in aqueous media, in contrast to other explosives such as research department explosive (RDX), picric acid, and trinitrotoulene (TNT). The siderophore PVD exhibited enhanced fluorescence quenching above 50% at 470 nm for a minimal concentration (38 nM) of NTO. The limit of detection estimated from interpolating the graph of fluorescence intensity (at 470 nm) versus NTO concentration is found to be 12 nM corresponding to 18% quenching. The time delay fluorescence spectroscopy of the PVD–NTO solution showed a negligible change of 0.09 ns between the minimum and maximum NTO concentrations. The in silico absorption at the emission peak of static fluorescence remains invariant upon the addition of NTO. The computational studies revealed the formation of inter- and intramolecular hydrogen-bonding interactions between the energetically stable complexes of PVD and NTO. Although the analysis of Stern–Volmer plots and computational studies imply that the quenching mechanism is a combination of both dynamic and static quenching, the latter is dominant over the earlier. The static quenching is attributed to ground-state complex formation, as supported by the computational analysis.

This research describes systematic investigations on sensing of high explosives such as picric acid (PA), RDX, NTO, and trinitrotoluene (TNT) in aqueous medium via fluorescence quenching of quinine sulfate (QS). Although all the explosives exhibit fluorescence quenching of QS, highest response is observed for PA. Fluorescence quenching of [Formula: see text][Formula: see text]50% (in contrast to pristine QS) at [Formula: see text][Formula: see text]390 nm is observed for 10 nm (2.29 [Formula: see text]g of PA dissolved in 20 [Formula: see text]l of distilled water). The analysis of the Stern–Volmer (SV) plot implies dominance of static quenching mechanism in comparison to dynamic quenching mechanism. Furthermore, the effect of operational temperature on fluoresce quenching response for PA has been investigated, and values of enthalpy, entropy, and Gibbs free energy of interaction at various temperatures are estimated. The temperature-dependent studies reveal that fluorescence quenching is due to formation of strong hydrogen bonds, complemented by computational analysis.