SOFT 2004 Meeting Abstracts - Society of Forensic Toxicologists

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COMPARISON STUDY OF SPE AND HS-SPME IN THE DETERMINATION OF METHADONE
AND ITS METABOLITES EDDP AND EMDP IN HUMAN HAIR USING GC-MS
L O'Hanlon l *, J S Oliveri, and K S Scott 2
IPorensic Medicine and Science, University of Glasgow, Glasgow, UK
2Department ofForensic Science and Chemistry, Anglia Polytechnic University, Cambridge, UK
The objective of this research was to develop and optimize a robust head-space solid phase microextraction for the
extraction of methadone and its metabolites from hair and to compare this method to a pre-existing solid phase
extraction method. Methadone (6-dimethylamino-4,4-diphenyl-3-heptanone hydrochloride) is a synthetic opioid
agonist with characteristics similar to those of morphine, including actions on the central nervous system and organs
composed ofsmooth muscle. Although structurally it has no resemblance to morphine, its analgesic and spasmolytic
properties have allowed it to be used as a substitute for heroin in opiate addiction programmes.
Aliquots of blank hair (IOmg) were spiked with methadone and EDDP at two different concentrations and incubated
in sodium hydroxide solution 1 M (Iml) with anhydrous sodium chloride. This was carried out in 4 ml amber screwtop
vials with a PTPE/siIicone septum. The vial was preheated for 20 min under agitation. The needle probe holding
the IOOJ,lm polydimethylsiloxane (PDMS) fibre was then pushed through the septum and the fibre was immersed in
the specimen for 20 min at a temperature of 75°C while agitated. The fibre was then transferred to the GC inlet. The
injection port (operated in splitlsplitless mode) was set to 225°C and the purge time to 3 min. The column
temperature was initially held at 80°C for 2 min, then increased to 280°C at lOOC/min and held for 5 min.
This SPME method was compared to the following SPE method. Aliquots of spiked hair (lOmg) were incubated in
methanol for ISh at 37'C. This methanol was then removed and the sample was sonicated with more methanol. The
methanolic fractions were combined and evaporated under nitrogen and reconstituted in distilled water and
phosphate buffer, pH 6. The samples were homogenised and applied to preconditioned Clean Screen columns.
These were selectively washed with various solvent and aqueous mixtures; Methadone and EDDP were extracted
using dichloromethane/isopropanol/concentrated ammonia (78:20:2). These fractions were then evaporated to
dryness under nitrogen and reconstituted in 25 J,ll of ethyl acetate. They were then analysed using the same GC-MS
chromatographic conditions. Relative recoveries of methadone and EDDP from hair were determined by comparing
the peak heights obtained from spiked hair with unextracted standards and both were determined to be above 5%.
The HS-SPME method proved to be fast and efficient and also has the advantages of being solvent free and
producing cleaner extracts.
This paper presents a comprehensive, comparative study of both SPE and HS-SPME of methadone and EDDP from
human hair and will report on the advantages and disadvantages of both methods.
Keywords: Methadone, Solid Phase Extraction, Solid Phase Microextraction
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