A Photoluminescence Technique for Detection of Gunshot Residue

Abstract

Rapid, convenient detection of gunshot residue on the hands of a suspect, following a shooting, can be accomplished by the photoluminescence determination of the presence of lead (Pb) and antimony (Sb), which originate in the cartiridge primer. Following the firing of a gun, the backs of both hands are washed in a stream of distilled water. Each hand washing is filtered, and the residue collected on a membrane filter is dissolved in hydrochloric acid. Lead(II)and Sb(III) form chloride ion complexes with the acid, which luminesce strongly upon selective ultraviolet excitation at low temperature. Upon excitation, the Pb and Sb complexes emit light with maxima at wavelengths characteristic for the two metallic elements. By the use of this procedure, it is possible to detect as little as 1.0 ng of Pb and 10 ng of Sb. The total time for sample collection and analysis is less than 30 min.