In this study, the correlation between smokeless powder (SP) and smokeless powder residues (SPR) was explored via Sørensen-Dice similarity coefficients and Pearson correlation coefficients; and the Sørensen-Dice similarity coefficients between SPR and expected pyrolysis products obtained from the burning of SP compound standards were explored to determine whether SPR composition may be predicted based on initial SP composition.
Following a shooting or explosive event, such as the explosion of an improvised explosive device, smokeless powders (SP) and smokeless powder residues (SPR) may be recovered as evidence. The analysis of SPR may allow for an association to the SP, which can provide an evidentiary link. The results of the current study indicated that the similarity between SP and SPR is highly composition dependent, with samples containing diphenylamine along with nitroglycerin or 2,4-dinitrotoluene exhibiting higher similarity scores, as well as those containing dibutyl phthalate. Comparison of SPR to expected pyrolysis products indicated that the ability to predict SPR composition is also dependent on the initial SP composition. The complexity of burning a mixture, such as SP, compared to burning single components may contribute to the generally low similarity coefficients observed in this comparison. (publisher abstract modified)