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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.forsciint.2009.12.046 Byline: M. Moller (a)(b), K. Aleksa (a), P. Walasek (a), T. Karaskov (a), G. Koren (a)(b) Keywords: Solid-phase microextraction; Hair analysis; Opiates; Gas chromatography-mass spectrometry Abstract: Opiate hair analysis continues to prove difficult due to the scarcity of hair sample and low drug concentrations. For this reason, we developed a sensitive method utilizing headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) for the detection of three principle opiates; codeine, morphine, and 6-acetylmorphine. Author Affiliation: (a) Motherisk Program, Division of Clinical Pharmacology & Toxicology, Hospital for Sick Children, , Toronto, Ontario Canada, M5G1X8 (b) Department of Pharmacology & Toxicology, University of Toronto, Toronto, Ontario, Canada Article History: Received 9 June 2009; Accepted 21 July 2009

A general method has been elaborated to characterize peak homogeneity. The method uses two detection techniques and ratio formation of two simultaneous signals, arising from the same detector cell section. The feasibility of the method is exemplified by the analysis of partially overlapping codeine-hydrocodone and completely overlapping codeine-oxycodone samples, where peak homogeneity could be characterized by dual CD and UV detection. The [S.sub.CD]/[S.sub.UV] ratio, and analogous ratios for other, coupled dual detection techniques, are proven to be concentration-independent intensive parameters of the analytes and can be used for identification purposes much more readily than retention times. The observed ratio clearly shows the pure section(s) of the peak. Component composition can also be calculated in the case of heterogeneous peaks, and the ratio shows even the enantiomeric purity/impurity if achiral chromatography is hyphenated with dual (CD and UV) detection.

Supercritical fluid extraction (SFE) using [CO.sub.2] modified with methanol (10%) was employed for the extraction of cocaine from human hair. Extraction conditions were developed by using designed experiments to characterize the effects of pressure, temperature, and percent methanol on the recovery of cocaine from hair. When compared to the conventional acid hydrolysis method for hair analysis, SFE was faster and gave higher recoveries. Amounts of cocaine, benzoylecgonine (cocaine metabolite), codeine, and morphine in a hair standard reference material were determined by SFE-gas chromatography/ mass spectrometry (GC/MS) and found to be in agreement with reported levels. Analyses of hair from forensic case studies are also reported.