The ability of various liquid extraction techniques to isolate the natural and artificial surface components of human scalp hair has been evaluated. These organic components largely consist of sebaceous lipids and hair treatment residues, and have shown promise for forensic identifications and comparisons. However, an optimized method for their analysis that combines high efficiency, small sample size, and broad selectivity must be developed and validated. In this study, ultrasound, Soxhlet, and pressurized-fluid extraction, as well as solid-phase microextraction were used to extract a composite hair sample from an Asian male (ages 10 to 18), with sample amounts ranging from 1 mg - 1.3 g. Extraction efficiencies ranged from 0.9% to 5.6%, and tended to increase with solvent polarity. Chemical analysis of the extracts using gas chromatography/mass spectrometry (GC/MS) showed that the hair sample used in this work contained large proportions of free fatty acids, squalene, cholesterol, and various wax esters. No significant differences were seen in the chemical composition of the various extracts, although the relative proportion of the lipids measured did change with solvent. All results were compared to a previously established method of on-line supercritical fluid extraction (SFE), which was found to offer similar extraction efficiency and selectivity, as well as greater potential for miniaturization and analysis of sample amounts of less than one milligram.
Citation: Journal of Forensic Sciences
Pub Type: Journals
gas chromatography/mass spectrometry, hair, lipids, sebaceous