A Novel Two-Step Method for the Detection of Organic Gunshot Residue for Forensic Purposes: Fast Fluorescence Imaging...

Area of Science:

• Forensic Science
• Analytical Chemistry
• Spectroscopy

Background:

• Standard forensic methods focus on inorganic gunshot residue (IGSR).
• Organic gunshot residue (OGSR) analysis is critical for comprehensive shooting incident investigations.
• A gap exists in current methodologies for effective OGSR detection and identification.

Purpose of the Study:

• To develop and validate a novel two-step analytical method for detecting and identifying organic gunshot residue (OGSR).
• To assess the efficacy of combining fluorescence hyperspectral imaging with Raman microspectroscopy for OGSR analysis.
• To provide a reliable method for OGSR detection in simulated crime scene scenarios.

Main Methods:

• A two-step approach was developed, beginning with fluorescence hyperspectral imaging for initial particle detection.
• Confirmatory identification of potential OGSR particles was performed using Raman microspectroscopy.
• Two types of OGSR samples on adhesive tape substrates were analyzed: one with known amounts and one mimicking crime scene tape-lifting.

Main Results:

• The developed two-step method successfully detected and identified all OGSR particles in both sample types.
• Characteristic Raman peaks for OGSR particles were identified at 850 cm⁻¹, 1287 cm⁻¹, and 2970 cm⁻¹.
• The method demonstrated high sensitivity and accuracy in identifying OGSR particles on adhesive tape.

Conclusions:

• The proposed fluorescence hyperspectral imaging and Raman microspectroscopy method offers a promising solution for OGSR detection and identification.
• This methodology enhances current gunshot residue analysis capabilities by addressing the need for OGSR characterization.
• The technique provides accurate and reliable results, supporting its application in forensic investigations.