Explosives: Overview

Abstract

This article provides a comprehensive overview of the properties of explosives, procedures relating to forensic examinations involving explosives and subsequent analytical methods for their identification. The different types of explosions and their characteristics is first described, followed by the various types of damage that can be caused to both buildings/structures and victims as result of an explosion. A thorough discussion of the principles and processes involved with the forensic and criminal investigation of explosives and post-explosion scenes is provided, and the main challenges facing first responders and lead investigative agencies and other priorities such as the preservation of life, health and safety, and disaster victim identification are also recognized. A review of the various analytical methods used for the analysis of explosives is then discussed. The following techniques are described: bulk sample tests include burning, canine detection, calorimetric, and chemical tests; trace detection tests including chromatographic methods such as thin layer chromatography, gas chromatography (GC), high pressure liquid chromatography (LC), capillary electrophoresis, and ion chromatography; spectroscopic or spectrometric methods such as infrared, ion mobility spectrometry (IMS), mass spectrometry (MS), scanning electron microscopy–energy dispersive X-ray spectroscopy, X-ray fluorescence, and X-ray diffraction; and source determination methods such as inductively coupled plasma mass spectrometry and isotope ratio mass spectrometry. Sampling, sample clean-up and extraction procedures are also described, and the complexities and approaches taken during post-explosion analysis is recognized. The criteria required for the identification of explosives in a forensic context, and the problems associated with the interpretation of results are also reviewed given the trace amount of material that may be identified in pre and post blast samples.