Abstract
Background: Detection of explosives (Nitroaromatic compounds) is one of the major issues faced in global security and, to date, remains a challenge even though some materials are developed for their detection. This study introduces the use of polyvinylpyrrolidone (PVP), a nonconjugated conducting polymer, as a potential fluorophore for sensing nitroaromatics. The stimuliresponse of fluorescence of PVP on interaction with energetic nitroaromatics was investigated in the present study.
Methods: Fluorescence quenching studies of 5% PVP was carried out by the addition of varying concentration of quenchers (m-dinitrobenzene, trinitrobenzene and 2,4,6-trinitrophenol). To study the effect of different solvents on fluorescence quenching, two different solvents were used, i.e., water and ethanol. The quenching studies of PVP with dinitrobenzene and trinitrobenzene were carried out in ethanol and 2,4,6-trinitrophenol was carried out in the water.
Results: The maximum emission peak intensity of PVP was observed at 445 nm in ethanol and 420 nm in water, which was quenched upon the gradual addition of quenchers. This shift in maximum peak intensity of PVP was understood from the change in the solvent polarity. UV-Visible and FTIR studies were also carried out to understand the nature of interaction taking place between the quenchers and PVP. The limit of detection (LOD) was observed as 1.8x10-3 M, 2.5x10-6 M, and 3.9x10-6 M for picric acid, dinitrobenzene and trinitrobenzene, respectively.
Conclusion: The results envisage PVP as a potential candidate for sensing energetic nitroaromatics with good sensitivity.
Keywords: Polyvinylpyrrolidone, fluorescence, quenching, nitroaromatics, limit of detection, exciplex.
Graphical Abstract
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