Benzodiazepines identified by capillary gas chromatography-mass spectrometry, with specific ion screening used to detect benzophenone derivatives.

We developed algorithms for confirmation and identification of benzodiazepines and their metabolites, initially detected in urine samples by enzyme-multiplied immunoassay (EMIT). These algorithms are based on the pattern of benzophenone derivatives of benzodiazepines obtained by gas chromatography-mass spectrometry (GC-MS) with use of a modified specific ion selection mode. Benzophenone derivatives were produced by acid hydrolysis of urine samples containing benzodiazepines and (or) their metabolites. We present mass spectra of the newer benzodiazepines--alprazolam, midazolam, and triazolam--and we determined the detection limit (0.2 mg/L) for these drugs as measured with the EMIT d.a.u. benzodiazepine assay and the ETS instrument (both from Syva Co.). We conclude that these algorithms are useful mostly in forensic toxicology in which unequivocal identification of benzodiazepines is the desired goal.