New source of evidence: Explosive traces in hair

This study examines the sorption of explosives [TNT, RDX, PETN, TATP] to hair during exposure to their vapors. In each test, three colors of hair were simultaneously exposed to explosive vapor. Washing, extracting, and gas chromatographic quantification protocols were developed, and replication of quantitative data was confirmed. Results show that sorption of explosives, via vapor diffusion, to black hair is significantly greater than to blond, brown or bleached hair. Furthermore, the rate of sorption is directly related to the vapor density of the explosive: TATP >>> TNT >> PETN > RDX. Using TNT as the prototype, persistence of the explosive upon standing in air and upon repeated washing with sodium dodecyl sulfate was demonstrated. This study indicates that hair can be a useful indicator of explosive exposure/handling. Work is in progress to develop this technique into an effective forensic tool.