Forensic analysis of smokeless powder particles recovered from the debris of an improvised explosive device can provide information about the type of smokeless powder used and can aid investigation ...efforts. In this study, quantitative methods were used to yield information about the difference in the chemical composition of the particles pre‐ and post‐blast. The technique, gas chromatography/vacuum ultraviolet spectroscopy (GC/VUV), was able to quantify nitroglycerin, 2,4‐dinitrotoluene, diphenylamine, ethyl centralite, and di‐n‐butyl phthalate in pre‐ and post‐blast smokeless powder particles using heptadecane as an internal standard. Post‐blast debris was obtained via controlled explosions with assistance from the Indiana State Police Bomb Squad. Two galvanized steel and two polyvinyl chloride pipe bombs were assembled. Two devices contained single‐base smokeless powder and two contained double‐base smokeless powder. 2,4‐dinitrotoluene and diphenylamine were successfully quantified in the single‐base smokeless powder post‐blast debris while nitroglycerin, diphenylamine, and ethyl centralite were successfully quantified in the double‐base smokeless powder post‐blast debris. Compounds were detected at concentrations as low as 9 μg of 2,4‐dinitrotoluene per mg, <3 μg of diphenylamine per mg, 131 μg of nitroglycerin per mg, and <3 μg of ethyl centralite per mg. Concentration changes between pre‐ and post‐blast smokeless powder particles were determined as well as microscopic differences between pre‐ and post‐blast debris for both smokeless powders in all devices. To our knowledge, this is the first use of GC/VUV for the quantification of explosives.
The storage and use of explosives is regulated at the state and federal level, with a particular focus on physical security and rigorous accounting of the explosive inventory. For those working with ...explosives for the training and testing of explosive‐detecting canines, cross‐contamination is an important concern. Hence, explosives intended for use with canine teams must be placed into secondary storage containers that are new, clean, and airtight. A variety of containers meet these requirements and include screw‐top glass jars (e.g., mason jars). However, an additional need from the explosive‐detecting canine community is secondary containers that can also be used as training aids whereby the volatiles emitted by explosives are emitted in a predictable and stable manner. Currently, a generally accepted method for the storage of explosives and controlled emission of explosive vapor for canine detection does not exist. Ideally, such containers should allow odor to escape from the training aid but block external contaminates such as particulates or other volatiles. One method in use places the explosive inside a permeable cotton bag when in use for training and then stores the cotton bag inside an impermeable nylon bag for long‐term storage. This paper describes the testing of an odor permeable membrane device (OPMD) as a new way to store and deploy training aids. We measured the evaporation rate and flux of various liquid explosives and volatile compounds that have been identified in the headspace of actual explosives. OPMDs were used in addition to traditional storage containers to monitor the contamination and degradation of 14 explosives used as canine training aids. Explosives were stored individually using traditional storage bags or inside an OPMD at two locations, one of which actively used the training aids. Samples from each storage type at both locations were collected at 0, 3, 6, and 9 months and analyzed using Fourier Transform Infrared (FTIR) Spectroscopy and Gas Chromatography–Mass Spectrometry (GC–MS) with Solid‐Phase Microextraction (SPME). FTIR analyses showed no signs of degradation. GC–MS identified cross‐contamination from ethylene glycol dinitrate (EGDN) and/or 2,3‐dimethyl‐2,3‐dinitrobutane (DMNB) across almost all samples regardless of storage condition. The contamination was found to be higher among training aids that were stored in traditional ways and that were in active use by canine teams.
With bombings in the United States on the rise for the first time since 2016, the detection and identification of explosives remains of pertinent interest to law enforcement agencies. This work ...presents two soon-to-be published research articles that focus on the detection and identification of explosives by both chemical instrumentation and canines. The first article, Quantitative Analysis of Smokeless Powder Particles in Post-Blast Debris via Gas Chromatography/Vacuum Ultraviolet Spectroscopy (GC/VUV), utilizes gas chromatography/vacuum ultraviolet spectroscopy (GC/VUV) to determine the difference in chemical composition of two smokeless powders in both pre- and post-blast conditions. The compounds of interest in this study were nitroglycerin, 2,4-dinitrotoluene, diphenylamine, ethyl centralite, and di-n-butyl phthalate. Concentration changes between pre- and post-blast smokeless powder particles were determined as well as microscopic differences between pre- and post-blast debris for both smokeless powders in all devices. To our knowledge, this is the first use of GC/VUV for the quantification of explosives. The second article, An Odor-Permeable Membrane Device for the Storage of Canine Training Aids, proposes the use of an odor-permeable membrane device (OPMD) as a standardized storage method for canine training aids. It is hypothesized that the OPMD would minimize cross-contamination between training aids, and that the OPMD could be used for canine training as well as storage. The goal of this research is to use flux and evaporation rate to quantify the explosive odor that escapes from the OPMD compared to unconfined explosives. Preliminary data suggests that there is an exponential relationship between relative boiling point and evaporation rate. It has been determined that compounds with higher boiling points have lower evaporation rates than compounds that have lower boiling points. The materials studied thus far are known odor compounds produced by explosive formulations. These include nitromethane, nitroethane, 1-nitropropane, r-limonene, and toluene.
Indiana University-Purdue University Indianapolis (IUPUI)
With bombings in the United States on the rise for the first time since 2016, the detection and identification of explosives remains of ...pertinent interest to law enforcement agencies. This work presents two soon-to-be published research articles that focus on the detection and identification of explosives by both chemical instrumentation and canines. The first article, Quantitative Analysis of Smokeless Powder Particles in Post-Blast Debris via Gas Chromatography/Vacuum Ultraviolet Spectroscopy (GC/VUV), utilizes gas chromatography/vacuum ultraviolet spectroscopy (GC/VUV) to determine the difference in chemical composition of two smokeless powders in both pre- and post-blast conditions. The compounds of interest in this study were nitroglycerin, 2,4- dinitrotoluene, diphenylamine, ethyl centralite, and di-n-butyl phthalate. Concentration changes between pre- and post-blast smokeless powder particles were determined as well as microscopic differences between pre- and post-blast debris for both smokeless powders in all devices. To our knowledge, this is the first use of GC/VUV for the quantification of explosives. The second article, An Odor-Permeable Membrane Device for the Storage of Canine Training Aids, proposes the use of an odor-permeable membrane device (OPMD) as a standardized storage method for canine training aids. It is hypothesized that the OPMD would minimize cross-contamination between training aids, and that the OPMD could be used for canine training as well as storage. The goal of this research is to use flux and evaporation rate to quantify the explosive odor that escapes from the OPMD compared to unconfined explosives. Preliminary data suggests that there is an exponential relationship between relative boiling point and evaporation rate. It has been determined that compounds with higher boiling points have lower evaporation rates than compounds that have lower boiling points. The materials studied thus far are known odor compounds produced by explosive formulations. These include nitromethane, nitroethane, 1- nitropropane, r-limonene, and toluene.
With bombings in the United States on the rise for the first time since 2016, the detection and identification of explosives remains of pertinent interest to law enforcement agencies. This work ...presents two soon-to-be published research articles that focus on the detection and identification of explosives by both chemical instrumentation and canines. The first article, Quantitative Analysis of Smokeless Powder Particles in Post-Blast Debris via Gas Chromatography/Vacuum Ultraviolet Spectroscopy (GC/VUV), utilizes gas chromatography/vacuum ultraviolet spectroscopy (GC/VUV) to determine the difference in chemical composition of two smokeless powders in both pre- and post-blast conditions. The compounds of interest in this study were nitroglycerin, 2,4-dinitrotoluene, diphenylamine, ethyl centralite, and di-n-butyl phthalate. Concentration changes between pre- and post-blast smokeless powder particles were determined as well as microscopic differences between pre- and post-blast debris for both smokeless powders in all devices. To our knowledge, this is the first use of GC/VUV for the quantification of explosives. The second article, An Odor-Permeable Membrane Device for the Storage of Canine Training Aids, proposes the use of an odor-permeable membrane device (OPMD) as a standardized storage method for canine training aids. It is hypothesized that the OPMD would minimize cross-contamination between training aids, and that the OPMD could be used for canine training as well as storage. The goal of this research is to use flux and evaporation rate to quantify the explosive odor that escapes from the OPMD compared to unconfined explosives. Preliminary data suggests that there is an exponential relationship between relative boiling point and evaporation rate. It has been determined that compounds with higher boiling points have lower evaporation rates than compounds that have lower boiling points. The materials studied thus far are known odor compounds produced by explosive formulations. These include nitromethane, nitroethane, 1-nitropropane, r-limonene, and toluene.
