Surface Contamination by TNT

Bender, Edward C.; Hogan, Austin W.; Leggett, Daniel C.; Miskolczy, G.; MacDonald, Stephen

doi:10.1520/jfs13358j

Cited by 21 publications

(13 citation statements)

References 3 publications

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“…(16) Although its vapor pressure is very low at room temperature, TNT has been shown to contaminate surfaces (such as wood, rubber, aluminum) placed near but not touching the TNT. (17) In the case of porous materials such as wood, significant TNT contamination was found not only on the surface but also throughout the wood. (17) This tendency of explosive materials to spread can be an advantage for forensic investigations and for efforts to prevent terrorist activities.…”

Section: Solid Sample Mixturesmentioning

confidence: 99%

“…(17) In the case of porous materials such as wood, significant TNT contamination was found not only on the surface but also throughout the wood. (17) This tendency of explosive materials to spread can be an advantage for forensic investigations and for efforts to prevent terrorist activities. However, it also implies that great care must be taken to ensure that any explosive material detected is from the sample of interest and not from previous contaminated samples (memory effects), from other samples stored in the laboratory, or from handling of the sample.…”

Section: Solid Sample Mixturesmentioning

confidence: 99%

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Laser‐ and Optical‐Based Techniques for the Detection of ExplosivesUpdate based on the original article by David L. Monts, Jagdish P. Singh and Gary M. Boudreaux,Encyclopedia of Analytical Chemistry, © 2000, John Wiley & Sons, Ltd

Hummel

Dubroca

2013

Encyclopedia of Analytical Chemistry

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A wide variety of optical‐ and laser‐based techniques have been and are currently being investigated as means of identifying and characterizing explosive materials. These efforts are hampered by the very low volatility of explosive compounds at room temperature and their tendency to ignite at higher temperatures where their vapor pressures are beginning to reach a regime where the species can be readily detected. Traditional, condensed‐phase absorption spectroscopy (both infrared (IR) and ultraviolet/ visible (UV/VIS)) requires larger samples than are frequently available and, although useful as confirmatory techniques, do not provide signatures that enable unique identification of species. The choice of nontraditional techniques for analysis of explosive materials is dependent upon the amount of sample available, the sample matrix, and sample‐imposed constraints upon the measurement. Raman spectroscopy can identify and quantify condensed phase explosive materials, but the detection limit depends upon substrate, excitation wavelength, and illumination area: limits of detection (LODs) vary from 0.05 ng for 2,4,6‐trinitrotoluene (TNT) on glass to 10 µg for nitroglycerin (NG) on silica gel. The other detection techniques considered require volatilization of either the explosive compound itself or more often of characteristic decomposition products, such as NO, NO 2 , or N 2 O. Using IR irradiation, researchers have demonstrated that photoacoustic spectroscopy (PAS) has detection limits ranging from 0.55 ppb (parts per billion) for vapor‐phase NG with 9 mm excitation to 220 ppm (parts per million) for vaporphase 2,4‐dinitrotoluene (DNT) with 6‐µm excitation. IR laser differential absorption detection of dissociation products NO, NO 2 , and/or N 2 O can achieve detection limits of a few picograms. Laser‐induced fluorescence (LIF) detection of the photofragments (typically NO) of explosive compounds yields detection limits in the tens to hundreds of ppb (by weight) range. Low LODs can be achieved using ion detection techniques: resonance‐enhanced multiphoton ionization (REMPI) spectrometry is capable of LODs for detecting vapor‐phase explosives compounds in the hundredths to tens of ppb range; ion mobility spectrometry (IMS) has vapor‐phase detection limits for common explosive compounds of typically 200 pg, but for some species can be significantly lower: for example, 1 pg for TNT.

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Section: Solid Sample Mixturesmentioning

confidence: 99%

Section: Solid Sample Mixturesmentioning

confidence: 99%

Laser‐ and Optical‐Based Techniques for the Detection of ExplosivesUpdate based on the original article by David L. Monts, Jagdish P. Singh and Gary M. Boudreaux,Encyclopedia of Analytical Chemistry, © 2000, John Wiley & Sons, Ltd

Hummel

Dubroca

2013

Encyclopedia of Analytical Chemistry

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“…These same vapors are also emitted by intact mines ) and contaminate their surfaces (Leggett et al 2000). Vapor-contaminated materials, themselves, remain a source of vapors for many days (Bender et al 1992). These emitted vapors are sorbed and concentrated on soil around buried landmines (George et al 1999).…”

Section: Tablesmentioning

confidence: 99%

Diffusion and Flux of Explosive-Related Compounds in Plastic Mine Surrogates

Cragin¹,

Leggett²

2003

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Canine detection of buried landmines is thought to be an olfactory process and efforts are now underway to develop electronic sensing of explosives vapors. The quantity of these vapors is critical to any chemical-sensing-based procedure for detecting landmines. Plastic-cased mines release vapors of explosive-related compounds (ERC) by permeation through the casing as well as through holes and cracks. Measurement of permeation contributions to the release flux was reported previously for a few intact mines. Here we determine permeation-driven fluxes and difiusivities by analysis of ERC release into water as a function of time. The solubility of TNT and diffusivities of TNT, 2,4-DNT, and 1,3-DNB in five polymeric materials potentially used in mine casings are reported for the first time. This information can be used to estimate ERC fluxes from TNT-filled mines encased in any of these materials. Direct measurement of the release fluxes from intact mines are feasible and were described previously. Calculated difiusivities of the nitroaromatics in these materials were similar to those reported in the hterature for other aromatic vapors. Diffusion was generally non-Fickian (concentration-dependent). TNT fluxes into Tedlar bags were also measured at 3,13, and 22° C for the five materials. The temperature dependence is well described by simple exponential relations of the van't HoflE/Arrhenius type, and an activation energy was calculated for the process. The temperature dependence of the fluxes was similar for all five materials. Fluxes of individual ERC components were also determined at 22° C and reflected their abundance in the headspace of the source explosive. Plastic/air partition coefficients of the contaminants ranged from 1 x 10^ to 3 x 10^ and were about an order of magnitude higher for TNT than for DNB and were intermediate for DNT.DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. AH product names and trademarks cited are the property of their respective owners.

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“…In addition, highly confined explosives are likely to emit only small amounts of vapor into their surroundings. Furthermore, it has been shown that vapors emanating from several nitroaromatic explosives tend to adsorb onto surrounding surfaces rather than undergo mass transport [3,4]. For these reasons, high detection sensitivity is critical.…”

Section: Introductionmentioning

confidence: 99%