At a shooting scene, gunshot residue (GSR) is collected from a suspect's hands. The definitive analytical method for GSR confirmation and the characteristic tri-elemental particle composition sought is:
- A Scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) identifying particles containing lead, barium, and antimony simultaneously ✓
- B Atomic absorption spectroscopy detecting lead alone from primer residue
- C Gas chromatography-mass spectrometry detecting nitrocellulose breakdown products
- D Inductively coupled plasma-mass spectrometry (ICP-MS) measuring total lead in hand swabs
Explanation
The gold standard for GSR analysis is SEM-EDX, which identifies individual spherical particles (formed from molten primer residue) containing the unique combination of lead (Pb), barium (Ba), and antimony (Sb) originating from lead styphnate, barium nitrate, and antimony sulphide in percussion primers. The co-localisation of all three elements in a single particle is the forensic criterion. Single elements can have innocent environmental sources. ICP-MS measures total metal load without particle morphology. Modern lead-free ammunition uses different elemental combinations (Ba-Al, Ba-Si-Sn).
Reference: The Essentials of Forensic Medicine and Toxicology (Narayan Reddy), 34th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.