Analysis of common opiates and heroin metabolites in urine by high-performance liquid chromatography

A separation of heroin, 6-monoacetylmorphine, codeine, pholcodine, dihydrocodeine and morphine using a 200 x 2 mm I.D., 3 microns silica column with dichloromethane-pentane-diethylamine-methanol mobile phase is described. Data on the determination of these compounds in a urine matrix based on this separation using a solid-phase pretreatment with Bond Elut Certify cartridges and nalorphine as an internal standard are shown. The compounds listed can be quantified at levels below that generally accepted as the cut-off level for the screening for opiates by enzyme immunoassay (EMIT) with detection limits for the different opiates ranging from 4 to 20 ng ml-1. Comparative data are shown of subject urine samples assayed for opiates by both the enzyme immunoassay and the proposed method. The utility of the method for the elimination of so-called false positives detected by EMIT due to the presence of medically prescribed and non-prescription opiates in urine is discussed.