Glass-Containing Gunshot Residue Particles: A New Type of Highly Characteristic Particle?

• NCJ Number: 200461
• Journal: Journal of Forensic Sciences Volume: 48 Issue: 3 Dated: May 2003 Pages: 538-553
• Author(s): Peter Collins; John Coumbaros; Graham Horsley; Bernard Lynch; K. Paul Kirkbride; William Skinner; Gunter Klass
• Date Published: May 2003
• Length: 16 pages
• Publication Format: Article
• Publication Type: Report (Study/Research)
• Language: English
• Country: United States of America

Annotation

This study sought to characterize glass-containing gunshot residue (GSR) particles by scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDX) and time-of-flight secondary ion mass spectrometry (TOF-SIMS), so as to establish the occurrence and variation of these particles in various types of 0.22 caliber ammunition and to explore the occurrence of these particles on hand and wound samples.

Abstract

A description of materials and methods addresses the standard glass samples, the recovery of glass particles from unfired 0.22 cartridge cases, the collection of gunshot residues from fired cartridge cases, the collection of GSR from hands and from wounds, the measurement of refractive index, and instrumental operating parameters. SEM-EDX that uses a thin polymeric window was shown to be a suitable technique for the detection and subsequent analysis of glass-containing GSR particles in which glass surfaces are exposed. The SEM-EDX results show that the gross composition of regions of the glass may remain substantially unaltered during firing. A survey of ammunition types indicated that borosilicate glass and then soda-lime glass were the most commonly used frictionators in 0.22 caliber ammunition, with some subclassification of these glasses being possible. The survey also confirmed that 0.22 caliber ammunition may contain lead; lead and barium; or lead, barium, and antimony-type primers; therefore, the technique described provides discrimination between some 0.22 caliber ammunition types based upon the gross elemental composition of the glass and the fused primer-derived residue. TOF-SIMS analysis of the representative particles extracted from a fired cartridge case exemplifies the strengths TOF-SIMS offers as a complementary technique to SEM-EDX. TOF-SIMS can characterize glass-containing GSR particles and has the capability for depth profiling, elemental mapping, and reliable detection of boron. This method also has the ability to remove extraneous surface debris by etching and can be used to measure trace element profiles. 24 figures, 1 table, and 32 references