Identification and highly selective differentiation of organic gunshot residues utilizing their elemental and molecular signatures

Firearm related evidence is of great significance to forensic science. In recent years, many researchers have focused on exploring the probative value of organic gunshot residue (OGSR) evidence, which is often bolstered by many factors including recoverability. In addition, OGSR analysis has shown the potential to achieve differentiation between OGSRs generated from various ammunition brands and/or calibers. Raman spectroscopy is a vibrational spectroscopic technique which has been used in the past for gunshot residue analysis-including OGSR specifically. Raman spectroscopy is a nondestructive, highly-selective, simple, and rapid technique which provides molecular information about samples. LIBS or Laser-Induced Breakdown Spectroscopy is a simple, robust, and rapid analytical method which requires minimal to no sample preparation and a small amount of sample for analysis. LIBS provides information on the elemental compositions of samples. In this study, Raman spectroscopy and LIBS were used together in sequence in an attempt to achieve the specific identification and characterization of OGSR particles from ammunition types which were closely related. The main goal was to determine if this method had the potential to differentiate between various ammunition types of the same caliber and produced by the same manufacturer, and generated under identical firing conditions. High-resolution optical microscopy documented the OGSR particles' morphologies and Raman

Automated summary

Firearm related evidence plays a significant role in forensic science. Researchers have been exploring the value of organic gunshot residue (OGSR) evidence, including factors like recoverability. Raman spectroscopy and LIBS are two nondestructive and rapid techniques used in this study to identify and characterize OGSR particles from closely related ammunition types. The goal is to differentiate between ammunition types of the same caliber and manufacturer, generated under identical firing conditions.