ENFSI proficiency test program on identification of GSR by SEM/EDX

Area of Science:

• Forensic Science
• Analytical Chemistry
• Materials Science

Background:

• Proficiency testing is crucial for ensuring accuracy in forensic analysis.
• Standardized methods for gunshot residue (GSR) detection are vital for reliable casework.
• Scanning Electron Microscopy with Energy-Dispersive X-ray Spectroscopy (SEM/EDX) is a primary technique for GSR analysis.

Purpose of the Study:

• To assess the performance of laboratories in detecting and identifying GSR particles using SEM/EDX.
• To evaluate the effectiveness of automated GSR particle search and detection methods.
• To identify potential systematic errors in GSR analysis through a split-level proficiency study.

Main Methods:

• Organized a proficiency test under the ENFSI Expert Working Group "Firearms."
• Utilized test materials with synthetic GSR particles (PbSbBa-containing) and environmental contaminants.
• Participating laboratories applied their own automated SEM/EDX methods for particle detection.

Main Results:

• Summarized and statistically evaluated the results from participating laboratories.
• Compared findings with previous proficiency studies on GSR analysis.
• Identified variations in the determination of PbSbBa-containing particles.

Conclusions:

• Proficiency testing highlights the need for method harmonization in GSR analysis.
• Variability in results suggests areas for improvement in automated SEM/EDX protocols.
• Further studies are recommended to refine GSR detection and identification techniques.