Determination of lead and antimony in firearm discharge residues on hands by anodic stripping voltammetry

When a person fires a gun, trace quantities of lead, antimony and barium are deposited on the hand. Detection of high levels of these trace metals on the hand of a suspect may therefore be significant evidence in an investigation. In this study conditions for the determination of lead and antimony in gunshot residues by anodic stripping voltammetry using a mercury-coated graphite electrode are established. A sample is collected by washing the hand in 1M hydrochloric acid. Lead is determined in a portion of this sample, with 1M hydrochloric acid as electrolyte. Antimony is determined in a second portion, with 4M hydrochloric acid as electrolyte. Prior separation or preconcentration steps are not required for either analysis. The procedure has been applied to samples obtained from five "normal" hands and five hands after they have fired a weapon.