High performance liquid chromatography-immunoassay of delta 9-tetrahydrocannabinol and its metabolites in urine.

High performance liquid chromatographic-immunoassay (HPLC-IA) profiles of cannabinoid metabolites in urine samples were obtained using four different antisera. The urines were chromatographed on a reverse phase system using a gradient of acetonitrile in water (pH 3.3) and fractions collected every 30 s. Some urine samples were hydrolyzed with methanolic sodium hydroxide before fractionation. Peaks of immunoreactivity were detected at a fraction corresponding to 11-nor-9-carboxy-delta 9-tetrahydrocannabinol (COOH-THC) and at an early eluting fraction; however, the profiles depended upon the specificity of the antisera used.