Luminescent Zn-MOF for detection of explosives and development of fingerprints

A luminescent 3D metal-organic framework [Zn(NDA)(AMP)] = PUC1 (where, NDA= naphthalene-2,6-dicarboxylic acid and AMP = 4-aminomethyl pyridine) was synthesized under solvothermal conditions. The synthesized 3D framework was fully characterized with...

The Role Of Polyvinylpyrrolidone as a Potential Fluorophore for the Detection Of Nitroaromatic Explosives.

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.

Peroxide Based Organic Explosives

In recent years progressively increasing terrorist activities, which use homemade explosives; such as acetone peroxide and other cyclic organic peroxides have led to worldwide awareness by security and defense agencies. Then the development of methodologies for the detection of cyclic organic peroxides have become an urgent need. Until quite recently, most of the current technology in use for trace detection of explosives had been unable to detect these energetic compounds. Differences in physical properties between cyclic organic peroxides is the main barrier for the development of a general method for analysis and detection of the peroxide explosives. In this short review, the most relevant contributions related to preparation, characterization and detection of the most important cyclic organic peroxides have been presented. It also includes few recent investigations about the toxicity and metabolism of some peroxide explosives.

Detection of Explosives by SERS Platform Using Metal Nanogap Substrates

Detecting trace amounts of explosives to ensure personal safety is important, and this is possible by using laser-based spectroscopy techniques. We performed surface-enhanced Raman scattering (SERS) using plasmonic nanogap substrates for the solution phase detection of some nitro-based compounds, taking advantage of the hot spot at the nanogap. An excitation wavelength of 785 nm with an incident power of as low as ≈0.1 mW was used to excite the nanogap substrates. Since both RDX and PETN cannot be dissolved in water, acetone was used as a solvent. TNT was dissolved in water as well as in hexane. The main SERS peaks of TNT, RDX, and PETN were clearly observed down to the order of picomolar concentration. The variations in SERS spectra observed from different explosives can be useful in distinguishing and identifying different nitro-based compounds. This result indicates that our nanogap substrates offer an effective approach for explosives identification.