Encapsulated XAD-2 extraction technique for a rapid screening of drugs of abuse in urine.

This paper describes a novel technique for the rapid screening of drugs of abuse in urine involving extraction with encapsulated Amberlite XAD-2 resin followed by gas chromatographic analysis. Each capsule is fabricated as a rigid, porous, polypropylene sphere, 2 cm in diameter, and contains 300 mg of the XAD-2 resin. Two mL of urine is shaken with one capsule under slight positive pressure for eight minutes. A sequential extraction is employed to obtain separate elution of the acidic-neutral and basic drugs. Identification is by dual column gas chromatography. The results, as given for spiked urine samples containing 16 commonly encountered drugs, were found to be linear and reproducible over both the therapeutic and toxic ranges. Extraction efficiencies using the encapsulated XAD-2 technique are comparable to those reported in literature for XAD-2 column chromatography. The purity of the extracts, as seen from the gas chromatographic analysis, is demonstrably better than that seen with the conventional procedures. There was minimal interference from polymer bleed. The total volume of solvents used in the sequential scheme is 5 mL. Total extraction time to achieve dried residues is 15 minutes.