Sample Collection, Preparation, and Quantitation in the Micellar Electrokinetic Capillary Electrophoresis of Gunshot Residues

Abstract

Application of micellar electrokinetic capillary electrophoresis (MECE) to gunshot residue (GSR) analysis was accomplished by developing appropriate sample collection and handling techniques. Masking adhesive-tape particle collection was used to minimize analyte losses and coextraction of sample matrix interferences associated with solvent swabbing collection methods. In addition, ethylene glycol (EG) was added to the extraction solvent to prevent analyte loss during evaporative preconcentration. β-naphthol, used as an internal standard, improved quantitative precision when EG was used in the MECE analysis of GSR's. Gunshot residues were collected from the hands of individuals who had discharged a firearm and analyzed by MECE using these sample collection and preparation techniques. Detection of gunpowder constituents, characteristic of the unfired gunpowder was obtained.