Solid-phase extraction and HPLC-UV confirmation of drugs of abuse in urine

A series of six liquid chromatographic methods were developed to confirm the presence of six classes of drugs of abuse in urine. The chromatographic separations were performed with a reversed-phase C8 column, except in the case of morphine, which was separated on a normal phase column. Isocratic and gradient elutions, ion pair technique, and UV detection were employed. Sample pretreatment involved the extensive application of solid-phase extractions and liquid-liquid extractions on solid supports. The specificity and sensitivity enabled the confirmation of morphine, benzoylecgonine, THC-COOH, amphetamine, and methamphetamine, six barbiturates, and nine benzodiazepines screened positive by EMIT in urine.