Mass screening and confirmation of methaqualone and its metabolites in urine by radioimmunoassay-thin-layer chromatography.

A sensitive, rapid, and specific procedure is described for the mass screening and confirmation of methaqualone (Quaalude) in urine specimens. The method is sensitive to 1.0 microgram/ml levels of total methaqualone excretion products (free methaqualone, free hydroxylated methaqualone metabolites, and conjugated hydroxylated methaqualone metabolites). The raw urine is screened directly by radioimmunoassay, which is reactive to all the methaqualone excretion products. Specimens that are screened positive are confirmed by thin-layer chromatography using a solvent system of ethyl acetate-1,2-dichloroethane-chloroform (75:15:10) which separates methaqualone and its four major metabolites without interference from other drugs or urinary substances. The distinctive spot pattern produced by the methaqualone metabolites makes false positive results nearly impossible.