Date of Submission
Master of Science in Forensic Science
Improvised explosive devices, Gas chromatography, Mass spectrometry--Forensic applications--Forensic applications
Improvised explosive devices (IEDs) are commonly used across the world, and if gloves are worn while creating an IED, explosive residue could be present on the gloves. This could be used as evidence to link a criminal to an IED and to the explosion site. The topic of this research is the detection of explosive residues removed from various glove materials and the effect of exposure to external conditions. This was done to determine how well explosive compounds can be extracted and detected off of gloves compared to a hard surface in different conditions, since that has not been investigated. Specifically, the detection of the explosives TNT, and TATP were examined from latex, nitrile, cotton, leather, and mechanic gloves using different swabbing methods to determine what method yielded the highest extraction efficiency. The swabbing methods included rayon swabs, cotton balls, alcohol wipes, flooding the glove with solvent, and direct extraction in solvent using methanol and acetonitrile. The samples were analyzed using GC-MS and the extraction efficiencies were then calculated.
Directly extracting the explosives from the gloves in solvent was determined to yield the highest extraction efficiencies from a preliminary test using 4-Nitrophenol. Acetonitrile was a better extraction solvent than methanol for leather gloves, but the two solvents were statistically the same for cotton gloves. Swabbing TNT from a hard surface yielded higher extraction efficiencies than extracting TNT from gloves. The extraction efficiency for swabbing TNT from the hard surface was 78.3% - 81.6%, compared to 26.7% - 41.9% for extracting from cotton gloves and 6.8% - 14.9% for extracting from leather gloves. Finally, the conditions of exposure to time, and the explosive residue being cleaned off of a hard surface were investigated to determine any changes in the detection of the explosive compounds. When the explosive sample was left on a hard surface for 24 hours before being swabbed, the extraction efficiency was significantly lower, most likely due to degradation of the explosive compounds.
The results of this research indicate the optimal swabbing method for different explosive compounds on a variety of gloves as well as how exposure to time and cleaning supplies affects how well these compounds are extracted and subsequently detected. These results can provide useful information in cases involving explosive residue on gloves, or similar fabric, as well as surfaces that are suspected to having been cleaned after exposure to explosive compounds.
Lamy, Shannon E., "Comparing the Efficiencies of Common Extraction Methods for Explosive Residues Off Various Surfaces Using Gas Chromatography/Mass Spectrometry" (2019). Master's Theses. 113.
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