Analysis of the human scent on the cartridge cases using GC×GC-MS/TOF

Importance of the Topic

In forensic investigations, human scent provides a resilient signature that survives extreme conditions and offers an alternative to traditional identification methods.

Objectives and Study Overview

This study aimed to evaluate the feasibility of matching human scent profiles on cartridge cases recovered from simulated crime scenes to individual donors.

• Four volunteers fired a weapon, producing 12 reference samples on glass beads and four unknown samples on cartridge cases
• Sampling across diverse surfaces including plastic, wood, and concrete

Methodology and Instrumentation

Scent compounds were desorbed and separated using comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry. Data alignment employed Kovats retention indices. Compound selection criteria included detection in at least one cartridge case sample and presence in 75% of volunteer references. The first 150 variables ranked by variance were used for area ratio comparisons and cluster analysis.

Instrumentation

Comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC-MS/TOF).

Main Results and Discussion

Cluster analysis successfully differentiated individual volunteers and matched unknown cartridge case samples to their donors. Trained canines provided complementary confirmation. Surface type had negligible impact on profile matching.

Benefits and Practical Applications

• Noninvasive forensic tool complementing fingerprint analysis
• Thermally stable scent markers enable evidence recovery after heat exposure
• Potential for trace-level identification on diverse substrates

Future Trends and Opportunities

• Standardizing sampling parameters across materials
• Reducing adsorption time for rapid field deployment
• Integrating scent analysis with fingerprinting workflows
• Expanding validation with larger cohorts, various firearms, and ammunition types

Conclusion

This proof-of-concept demonstrates that GC×GC-MS/TOF profiling of human scent on cartridge cases can reliably associate samples to individuals, offering a robust addition to forensic identification strategies.

References

• Ladislavova N; Pojmanova P; Vrbka P; Snuparkova J; Urban S Comprehensive analysis of human scent thermal stability PLOS ONE 18 2023
• Dolezal P; Furton KG; Lnenickova J; Kyjakova P; Skerikova V; Valterova I; Pinc L; Urban S Multiplicity of the human scent signature Egypt J Forensic Sci 9 7 2019