UNIFORM SOLID-PHASE EXTRACTION PROCEDURE FOR TOXICOLOGICAL DRUG SCREENING IN SERUM AND URINE BY HPLC WITH PHOTODIODE-ARRAY DETECTION

In this HPLC-diode-array detection method for toxicological drug scree ning, a mixed-mode solid-phase extraction procedure is optimized for i solation of a broad range of drugs from serum and urine. Basic, neutra l, and weakly acidic drugs are uniformly recovered. The extract from t he solid-phase cartridge is readily injected to a reversed-phase HPLC column for separation by gradient elution. Unknown drugs and metabolit es in urine and serum samples from acute drug poisoning cases are rapi dly identified by matching their retention times and ultraviolet spect ra with hundreds of reference compounds in the library. Urine metaboli tes of common toxicants from various medications and drugs of abuse ar e recorded, with their changes of retention times and ultraviolet spec tra as related to their metabolic transformations. Glucuronide conjuga tes of common benzodiazepines, tricyclic antidepressants, and beta-blo ckers are examined directly without chemical or enzymatic hydrolysis. The system is reliable for diverse clinical investigations of drug ove rdoses, drug-induced psychoses, and substance abuse.