SOFT - TIAFT 1998 Scientific Session 8 Friday October 9, 1998
Click Picture Rokus A. de Zeeuw, Jaap Wijsbeek and Jan Piet Franke

University Centre for Pharmacy, Groningen-Utrecht Institute of Drug Exploration, Deusinglaan 1, 9713 AV Groningen, The Netherlands

Broad spectrum drug screening in analytical toxicology requires that all relevant substances be isolated, detected and identified, regardless of their structure and/or polarity. To this end, we developed a systematic SPE approach for drug isolation from biological fluids [Chen et al., J. Forensic Sci. 37 (1992) 61-71]. Since speed and cost-effectiveness are key issues, we have evaluated disc-format extraction for the above purpose.

Discs were SPEC.PLUS.C18AR/MP3 columns, providing hydrophobic and cation exchange interaction. Blank human urine was spiked at 2 mg/L with pentobarbital, secobarbital, methaqualone, diazepam, phencyclidine, lidocaine, methadone, imipramine and codeine, thus representing a variety of drug classes. Urine specimens (2 mL), were diluted with 2 mL phosphate buffer pH 5.0, and the mixture was applied to the preconditioned disc. Washing was done with 1 mL water. Acidic and neutral drugs were eluted with 1 mL ethyl acetate-acetone 1:1, followed by eluting basic drugs with 1 mL ammoniated ethyl acetate. Extracts were examined by GC-FID to check cleanliness, recoveries and reproducibilities.

The discs showed good extraction efficiencies for all drugs, with little or no matrix interferences. Recoveries were 75-100% with CV's around 5%. As compared to our standard SPE method mentioned above, the disc procedure allowed a reduction of both elution volumes and total processing times by some 65%.

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