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Profiling the chemical composition of explosives

Citation

Johns, CA and Hutchinson, JP and Breadmore, MC and Guijt, RM and Hilder, EF and Dicinoski, GW and Haddad, PR, Profiling the chemical composition of explosives, Chemistry in Australia, 76, (11) pp. 30-35. ISSN 0314-4240 (2009) [Refereed Article]


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Abstract

The analysis of post-blast explosive residues has become an essential tool in counterterrorism initiatives.

Explosives based on inorganic salts and peroxides can be constructed using readily available, low cost, and legally purchased components. Examples of their recent use in terrorist bombings include: the Unabomber (USA, 19851996), the bombing of the World Trade Center (USA, 1993), the Murrah Federal Building (USA, 1995), several terrorist attacks in Indonesia (2002, 2005) and attacks on public transport systems in Madrid (Spain, 2004) and London (UK, 2005).

Identification of explosives is a topic of considerable interest to forensic scientists and counter-terrorism authorities. The broad area of explosives analysis can be divided into two sub-areas: detection and identification of explosives or their major ingredients prior to detonation (pre-blast screening analysis), or identification of explosives by analysis of debris and residues after detonation (post-blast detection analysis). Pre-blast analysis is a challenging problem that requires the ability to rapidly screen for the presence of inorganic and organic starting materials used to make explosive devices. Such screening is currently being used at fixed locations, such as airport terminals, in efforts to apprehend potential terrorists. On the other hand, post-blast analyses are required to determine the type and composition of an explosive after detonation has occurred. Explosive devices have a vast range of chemical compositions, hence a forensic scientist must be equipped with tools that enable the quantitative analysis of the evidence collected in these cases.

In our laboratory, we develop analytical methods which can be used for both pre-blast and post-blast applications. However the main focus of this article will be on the postblast analysis of "home-made" devices (sometimes also referred to as "improvised explosives" or "improvised explosive devices (IEDs)") constructed from low explosives. Inorganic home-made explosives employ vigorous oxidation/reduction chemical reactions using strong inorganic oxidisers, such as nitrate, perchlorate or chlorate which can be obtained or refined from commercial sources. High explosives, such as nitrated organic compounds (eg.TNT, RDX, PETN), are much more difficult to obtain because their sale, storage and use are highly regulated.

Some of the analytical methods previously used for the analysis of inorganic explosives include ion chromatography (IC), capillary electrophoresis (CE), scanning electron microscopy-energy dispersion X-ray, mass spectrometry, X-ray powder diffraction, infrared, atomic absorption spectroscopy and various spot tests. However, many of these techniques are not sensitive or specific enough for the analysis of inorganic anions or cations in explosive residues. We have found that the analytical techniques of IC and CE offer complementary, sensitive and selective technology for determining a large range of inorganic ions of relevance to the chemical identification of these types of explosives.

Item Details

Item Type:Refereed Article
Keywords:explosives, post-blast explosive residues, detection, profiling, chemical composition
Research Division:Chemical Sciences
Research Group:Analytical Chemistry
Research Field:Separation Science
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Chemical Sciences
Author:Johns, CA (Dr Cameron Johns)
Author:Hutchinson, JP (Dr Joseph Hutchinson)
Author:Breadmore, MC (Professor Michael Breadmore)
Author:Guijt, RM (Dr Rosanne Guijt)
Author:Hilder, EF (Professor Emily Hilder)
Author:Dicinoski, GW (Associate Professor Gregory Dicinoski)
Author:Haddad, PR (Professor Paul Haddad)
ID Code:59556
Year Published:2009
Deposited By:Austn Centre for Research in Separation Science
Deposited On:2009-12-09
Last Modified:2012-12-13
Downloads:3,363 View Download Statistics

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