Analysis of Gunshot Primer Residue Collection Swabs Using Flameless Atomic Absorption Spectrophotometry and Inductively Coupled Plasma-Atomic Emission Spectrometry: Effects of a Modified Extraction Procedure and Storage of Standards

Two modifications to a previously reported extraction procedure for determination of antimony, barium, and lead in gunshot primer residue swab extract solutions have been studied. Removal of cotton tips from swabs by cutting their shafts results in extraction efficiencies for all elements that compare favorably with those obtained by complete removal of the cotton from the swab shaft. Swab-mounted standards can be made and stored in a dry condition for periods of at least four months before use without adverse effects on analytical results. Long-term relative precision estimates for the combined extraction and analysis are approximately 5% for all three elements.