Date of Award
Bachelor of Science
As crimes involving firearms continue to be prevalent, forensic methods processing firearms evidence must keep pace with the changes in said evidence. Scanning Electron Microscopy with Energy Dispersive Spectroscopy, or SEM-EDS, is a method that targets the inorganic portions of gunshot residue (GSR) evidence, namely lead, barium, and antimony, to characterize a cartridge used at a crime scene, and was the most often used analysis method for characterizing ammunition cartridges. The rise of lead-free ammunition has made it so that SEM-EDS alone is not sufficient for the characterization of inorganic gunshot residue (IGSR), and studies have shifted towards being able to characterize GSR based on the organic portion of ballistic evidence, namely Organic Gunshot Residue (OGSR) and their precursor smokeless powders. OGSR and smokeless powders are composed primarily of nitrogen-based compounds. One such method that has potential to characterize OGSRs and smokeless powders is Raman spectroscopy. A database of Raman spectra for the smokeless powder from ammunition cartridges would in theory be very useful for investigative purposes, but first it needs to be determined if this method is viable for investigation. In this work, Raman spectroscopy was used to analyze samples of smokeless powders from twelve types of ammunition, sourced from three manufacturers from 9mm or .38 calibers. These samples included lead-free primer and total synthetic jacket cartridges. Spectra were generated to compare to one another to see if it was possible to differentiate both individual spectra and particular groups, such as manufacturer, caliber, and grain weight. It was found that it was possible to distinguish individual spectra from one another, with the most helpful ones being the 1650 cm-1 and 1590 cm-1 peaks, but no pattern could be found on any particular category, supporting the idea that each sample needs to be treated as an individual case.
Bartlett, Nathan, "Comparison of Raman Spectra of Smokeless Powders for Cartridge Differentiation" (2021). Chemistry. 18.
Available for download on Wednesday, December 01, 2021