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Title: The analysis of organic ballistic materials
Author: Dalby, O. J.
Awarding Body: Nottingham Trent University
Current Institution: Nottingham Trent University
Date of Award: 2011
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Both gas chromatography/mass chromatography (GC/MS) and solid phase microextraction (SPME) methodologies have been developed for the extraction and analysis of compounds encountered in relation to unburned propellant powders from firearm ammunitions. These methods allowed the detection of 27 compounds that may be present in organic gunshot residues (OGSR). The developed methodologies were applied to the analysis of unburned propellant and OGSR from spent ammunition cartridges and fabrics subjected to firearm discharges. Throughout the study a total of 16 ammunition types where investigated. Work carried out on the suitability of various SPME fibre types showed that 65μm PDMS/DVB was the most appropriate type for extracting the compounds of interest. Extractions carried out on unburned propellant powders showed that all of the ammunitions analysed produced different chromatographic results. All of the ammunitions in the analysed population could be differentiated from one another; it was determined to be highly unlikely that false matches could occur. Extractions from spend cartridges showed that some of the compounds originating from the precursor propellants remained, with many compounds being lost during discharge. In some examples, however, all compounds in the unburned propellant were extracted from spent cartridges cases. The amount of variability of compound abundances between spent cases of the same ammunition types was shown to be much greater than the variability between unburned propellant samples. It was, therefore, concluded that firearms discharges are likely to be non-reproducible events, with varying amounts of non-combusted materials remaining in each case. These results were considered to have implications when carrying out ―time since discharge‖ back calculations on cases. The collection and extraction of shot fabric samples were carried out using Nylon evidence bags, traditionally used for the collection of fire/arson materials. Results from this work showed that for some ammunitions it was possible to link extracts from fabrics to spent cartridge cases and unburned propellant powders, by matching compounds present in the originator propellant to residue extracts. For other ammunition types it was shown to be possible to link fabric extracts to spent cases directly, by matching the compounds present in both.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available