High-performance liquid chromatography of benzophenone derivatives for the determination of benzodiazepines in clinical emergencies.

A screening procedure for fifteen 1,4-benzodiazepines in biological material (urine), suitable for clinical toxicology, is described. The benzodiazepines and/or their metabolites are hydrolysed to their benzophenones; after alkalinization, the benzophenones are extracted with chloroform. The extract is evaporated to dryness and the dried residue is dissolved in methanol and analysed by high-performance liquid chromatography on a reversed-phase column at 254 nm with methanol-water (1:1) as eluent.