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Sniffing Out Explosives

NCJ Number
208916
Journal
Law Enforcement Technology Volume: 32 Issue: 2 Dated: February 2005 Pages: 68,70-72,74-76,78,79
Author(s)
Doug Hanson
Date Published
February 2005
Length
9 pages
Annotation
After describing characteristics of explosives, this article discusses the specifications and uses of various portable explosive sniffer devices and bomb-sniffing dogs, as well as the selection of the appropriate handheld model.
Abstract
Explosives can be grouped into four categories based on their primary chemical components: polynitro aromatics; nitrate-esters, nitramines; inorganic nitrates compounds; and chlorates. There are two principal types of explosives: low-order (velocity) explosives that burn and high-order (velocity) explosives that detonate. A variety of handheld explosives detection devices are available for the detection of organic chemical vapors. A sniffer detection device is an instrument that takes in a sample of air, processes it through a detector, and then identifies and calculates the approximate quantities of explosive material in the air sample. Most explosives have relatively low vapor pressures that result in a lower number of the chemical's molecules being released from the material. For this reason, detectors for explosives must have higher sensitivity than most detectors or the capacity to sample a large volume of air and concentrate the sample, a process that adds time to the analysis process. This article describes several analytical detection methods used with the devices; namely, ion mobility spectrometry, gas chromatography/surface acoustic wave, thermo-redox, and electron-capture detector. A bomb-sniffing dog is valuable in examining a room full of cargo or luggage. The dog will often go quickly to the area where an explosive is located; whereas, an officer with a chemical detector may have to test many items before locating the suspect material. Features important in a handheld detector are portability and ease of use, as well as the ability to discriminate between explosives and the myriad of other organic chemicals that might be present in a specific environment.