SPEC disc solid-phase extraction for rapid broad-spectrum drug screening in urine.
Broad-spectrum drug screening requires that all relevant substances be isolated, detected, and identified, regardless of their structure and/or polarity. To this end, systematic solid-phase extraction (SPE) approaches for drug isolation from biological fluids are required. Because speed and cost effectiveness are key issues in analytical toxicology, we have evaluated a disc-format extraction device for this purpose and compared the latter with an existing packed-bed column-format method. The discs were SPEC.PLUS.C18AR/MP3 cartridges with 10-mL solvent reservoirs, providing hydrophobic and cation exchange interactions. Blank human urine was spiked at 2 microg/mL with a selection of acidic, neutral, and basic drugs representing a variety of relevant drug classes. Urine specimens (2 mL) were diluted with 2 mL 0.1 M phosphate buffer (pH 5.0) and then 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), and basic drugs were eluted with 1 mL ammoniated ethyl acetate. The eluates were collected separately, evaporated down to about 0.1 mL, and analyzed by gas chromatography-flame-ionization detection to check cleanliness, recoveries, and reproducibilities. The discs showed good extraction properties for all drugs and were easy to handle. Recoveries were 75-100% with coefficients of variation of around 5%. The resulting eluates showed only a few matrix interferences. As compared to our standard SPE method with packed-bed columns, the disc procedure allowed reductions in elution volumes and total processing time of approximately 60-65%.
de Zeeuw
R A
RA
Department of Analytical Chemistry and Toxicology, University Centre for Pharmacy, Groningen, The Netherlands. r.a.de.zeeuw@farm.rug.nl
Wijsbeek
J
J
Franke
J P
JP
D001463:Barbiturates / Q000652:urine*; D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003975:Diazepam / Q000652:urine*; D005069:Evaluation Studies as Topic; D005410:Flame Ionization; D005554:Forensic Medicine / Q000379:methods; D006801:Humans; D009294:Narcotics / Q000652:urine*; D010622:Phencyclidine / Q000652:urine*; D015203:Reproducibility of Results; D015813:Substance Abuse Detection / Q000379:methods*
D001463:Barbiturates; D009294:Narcotics; D010622:Phencyclidine; D003975:Diazepam