|SOFT - TIAFT 1998||Scientific Session 8||Friday October 9, 1998|
|SPEC DISCS FOR RAPID BROAD SPECTRUM DRUG SCREENING IN URINE|
|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%.