triacetone-triperoxide and 2-4-dinitrotoluene

Canines remain the gold standard for explosives detection in many situations, and there is an ongoing desire for them to perform at the highest level. This goal requires canine training to be approached similarly to scientific sensor design. Developing a canine training regimen is made challenging by a lack of understanding of the canine's odor environment, which is dynamic and typically contains multiple odorants. Existing methodology assumes that the handler's intention is an adequate surrogate for actual knowledge of the odors cuing the canine, but canines are easily exposed to unintentional explosive odors through training material cross-contamination. A sensitive, real-time (∼1 s) vapor analysis mass spectrometer was developed to provide tools, techniques, and knowledge to better understand, train, and utilize canines. The instrument has a detection library of nine explosives and explosive-related materials consisting of 2,4-dinitrotoluene (2,4-DNT), 2,6-dinitrotoluene (2,6-DNT), 2,4,6-trinitrotoluene (TNT), nitroglycerin (NG), 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), pentaerythritol tetranitrate (PETN), triacetone triperoxide (TATP), hexamethylene triperoxide diamine (HMTD), and cyclohexanone, with detection limits in the parts-per-trillion to parts-per-quadrillion range by volume. The instrument can illustrate aspects of vapor plume dynamics, such as detecting plume filaments at a distance. The instrument was deployed to support canine training in the field, detecting cross-contamination among training materials, and developing an evaluation method based on the odor environment. Support for training material production and handling was provided by studying the dynamic headspace of a nonexplosive HMTD training aid that is in development. These results supported existing canine training and identified certain areas that may be improved.

Topics: Animals; Bridged Bicyclo Compounds, Heterocyclic; Cyclohexanones; Dinitrobenzenes; Dogs; Drug Contamination; Explosive Agents; Heterocyclic Compounds, 1-Ring; Mass Spectrometry; Nitroglycerin; Pentaerythritol Tetranitrate; Peroxides; Triazines; Trinitrotoluene; Volatilization

Determination of the dynamic nature of vapor/odor release has application in a wide variety of systems. This study applies automated solid-phase microextraction (SPME) utilizing an externally sampled internal standard (ESIS) to determine the vapor-time profile of odor delivery devices for three classes of explosive compounds. The profiles of delivery systems for target odorants 2,4-dinitrotoluene (2,4-DNT), 2-ethyl-1-hexanol (2-EH), and triacetone triperoxide (TATP) as canine training aids were compared over a period of 70 h. Strategies for evaluating the vapor-time profile of components with widely differing volatility are considered. An approach to quantifying the vapor concentration is described. The differences in the vapor-time profiles are examined and suggestions for selecting the best representative odor delivery technique are outlined.

Topics: Dimethylpolysiloxanes; Dinitrobenzenes; Gas Chromatography-Mass Spectrometry; Heterocyclic Compounds, 1-Ring; Hexanols; Odorants; Peroxides; Reference Standards; Solid Phase Microextraction; Temperature