Defense Date
2023
Document Type
Directed Research Project
First Advisor
Kelli Simon
Second Advisor
Eric Hazelrigg
Third Advisor
Ryan Bain
Abstract
Since its invention in 1884, smokeless powder has been of scientific interest. During World War II, research initially focused on developing methods to evaluate powders' stability. However, today, the focus has shifted to developing instrumental techniques sufficient for forensic classification and comparison work. Smokeless powder is typically encountered in forensic science casework involving firearms and explosives. In forensic investigations, determining the exact formulation of smokeless powders is challenging due to their complex chemistry and the proprietary nature of production. LC-MS and GC-MS techniques have been used to analyze intact and post-blast smokeless powders. Despite the vast amount of research that has been conducted to develop instrumental methods capable of analyzing smokeless powders, to this author's knowledge, research has yet to be conducted to develop an optimized solvent extraction method for use prior to instrumental analysis. This study utilized a 13-minute GC-MS method that can detect 14 analytes to develop and evaluate an optimized solvent extraction method. Results indicated that dichloromethane (DCM), the solvent traditionally used for smokeless powder extractions, had an average extraction efficiency of approximately 4-30% and required a large amount of sample (approximately 10 mg, or 2-20 particles) to detect analytes present at <2% w/w. The optimized solvent composition for enhanced extraction and detection of minor analytes was found to be 1:1 v/v DCM:ACN with a 15-minute extraction time. Here, minor analytes such as 2-NDPA were detected from as low as 0.5 mg of powder. Further, the ability to detect major characteristic analytes (e.g., nitroglycerin) was possible in particles with mass as low as 0.08 mg.
Rights
© The Author(s)
Is Part Of
VCU Master of Science in Forensic Science Directed Research Projects
Date of Submission
12-8-2023