NCJ Number
76891
Journal
Journal of Forensic Sciences Volume: 26 Issue: 2 Dated: (April 1981) Pages: 302-312
Date Published
1981
Length
11 pages
Annotation
A rapid yet reliable method for determining the presence of antimony, barium, and lead in gunshot residue using automated atomic absorption spectrophotometry is described.
Abstract
A Perkin-Elmer Model 500 microcomputer-controlled atomic absorption spectrophotometer, equipped with a simultaneous double-beam background corrector, built-in automatic wavelength scanning and selection, and magnetic card reader, was used for measurements. Gunshot residues were removed from the palms and backs (web, forefinger, and thumb) of the hands of persons in various occupations, suspected suicides, homicide victims, and others for analysis and comparison; and test firings with various 0.22, 0.25, 0.32, and 0.38 caliber weapons were conducted. Residues were collected with cotton swabs and 5 percent nitric acid and leached overnight in nitric acid. Enhanced reproducibility was achieved when an automatic injector system was used instead of the traditional manual pipet dispenser. The method eliminates the need for constant operator attention without sacrificing reliability and sensitivity. Among the data tables included are those providing data from occupational handblanks, test firings and handblanks, cases involving confirmed or highly suspected suicides and nonsuicidal incidents, and swabbings from homicide victims. Other tables provide data obtained from test firings of the various weapons and comparison data for manual injection and automatic sampling. A 26-item reference list is included.