NCJ Number
130220
Journal
Journal of Forensic Sciences Volume: 36 Issue: 3 Dated: (May 1991) Pages: 886-893
Date Published
1991
Length
8 pages
Annotation
The application of an electrochemical method for nitrite ion, lead, and antimony to gunshot residue (GSR) analysis is described.
Abstract
In this method, the nitrite ion in the sample is chemically converted to a diazonium ion which is then detected by differential pulse voltammetry in nitric acid. The peak current for the reduction of the diazonium ion is proportional to the nitrite concentration up to 400 ppb nitrite (r = 0.9995). The absolute detection limit of this method is approximately 0.01 micrograms of nitrite which is ten times smaller than that of previously reported spectrophotometric methods for nitrite in GSR samples. The method also incorporates lead detection from the same GSR sample in the same voltammetric scan and antimony by anodic stripping voltammetry. This method is also applied to GSR samples obtained in test firings. The amount of nitrite found in these samples is consistent with the amounts reported for the spectrophotometric method for nitrite. In addition, results of analysis of residues collected from persons who had not recently fired a weapon are also presented. The procedure described constitutes a sensitive, inexpensive, and rapid method for the analysis of metallic and nonmetallic components of a GSR sample. 2 figures, 2 tables, and 24 references (Author abstract modified)