Cooper G.A.A., Oliver J.S.

Department of Forensic Medicine and Science, University of Glasgow, Glasgow, G12 8QQ, Scotland, UK

A method is described for the efficient extraction of methadone and its two major metabolites, EDDP (2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine) and EMDP (2-ethyl-5-methyl-3,3-diphenyl-1-pyrroline), from whole blood.
The procedure combines extraction on ISOLUTE^® CONFIRM mixed-mode SPE columns and GC/MS analysis, with deuterated methadone as the internal standard.
The optimum extraction conditions for all three drugs, was investigated for spiked whole blood. The developed method is easier and faster than the current LLE procedure employed within our laboratory and produces cleaner extracts.
Calibration curves were linear over the concentration range of 0 - 600 ng/mL (r² > 0.99), with recoveries greater than 90% for all three drugs.
The concentration of methadone and its metabolites in postmortem blood was determined in fatal cases using the developed SPE method and compared with results obtained using LLE.