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 non-conjugated conducting polymer as a potential fluorophore for sensing nitroaromatics. The stimuli - response 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 was carried out in ethanol and 2,4,6-trinitrophenol was carried out in water.
Results:
The maximum emission peak intensity of PVP was observed at 445nm in ethanol and 420nm in water which was quenched upon gradual addition of quenchers. This shift in maximum peak intensity of PVP was understood from the change in the solvent polarity. UV-Visible and FT-IR 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 1.8x10-3M, 2.5x10--6M, and 3.9x10-6 M for picric acid, dinitrobenzene andtrinitrobenzene respectively.
Conclusion:
The results envisage PVP as a potential candidate for sensing energetic nitroaromatics with good sensitivity.
Towards the Development of a Low-Cost Device for the Detection of Explosives Vapors by Fluorescence Quenching of Conjugated Polymers in Solid Matrices