Volume 36, Issue 3 (May 1991)
A Sensitive Electrochemical Method for the Analysis of Nitrite Ion and Metals in Gunshot Residue
A method for the analysis of nitrite ion and metals in a single gunshot residue sample using electrochemical methods of detection is described. In this method, nitrite ion present in the sample is chemically converted to a diazonium ion, which is then detected by differential pulse voltammetry. The peak current for the reduction of the diazonium ion is proportional to the nitrite concentration up to 400 ppb nitrite (r = 0.9995), with an absolute detection limit of 0.01 μg nitrite. Lead ion present in the gunshot residue sample is detected in the same voltammetric scan, and antimony is subsequently detected by anodic stripping voltammetry. The method has been successfully applied to a number of samples obtained in test firings.