Trace Evidence Analysis of Human Hair by On-line Supercritical Fluid Extraction-Gas Chromatography/Mass Spectrometry: A Feasibility Study (NIJ Report 600-99)

The study took place because SFE-GC/MS has been proposed as a method for characterizing samples that consist of only micrograms to 1 milligram of sample of material. The methods offers a number of benefits. These include increased sensitivity compared with liquid extraction methods, as well as higher recoveries of volatile species that would be lost during a multistep liquid extraction and concentration. SFE-GC/MS may be the only way of obtaining qualitative and semiquantitative chemical information from a sample in some sample-limited cases. The current research used hair samples of 100 micrograms to 1 milligram of hair collected from 20 volunteers by a procedure approved by the National Institute of Standards and Technology Human Ethics Research Board. The research sought to distinguish children's hair from adults' hair by the relative abundances of squalene and cholesterol, to determine of analyses produced consistent profiles of individuals' hairs and distinguished them from the hair of other individuals, and to use a blind procedure to match blind samples with hair samples from the same individuals. Results suggested that analysis of the surface components of small hair samples by SFE-GC/MS may help match hair samples taken at a crime scene with those of specific individuals. Findings support the desirability of further study of a number of factors that could influence the chemical profile of the surface components from an individual's hair, as well as the reproducibility of that chemical profile. Figures, tables, footnotes, 6 suggested readings, and appended SFE-GC/MS chromatograms of the 20 hair samples