A sensitive evidence of trace concentrations of benzodiazepines and their metabolites in urine can be enabled after special sample preparation including enzymatic hydrolysis, special solid phase extraction, silylation and folowing analysis by gas chromatograhpy with mass spectrometry in electron impact mode. After optimalization of the procedure the extraction recovery values in the range 50 - 85 % are achieved. The scale of retention times with basic mass spectral data are presented for the spectrum of silylated benzodiazepines which can overlap some gaps in the standard toxicological literature up to now available.

        Key words: Benzodiazepine derivates - biotransformation - metabolites, toxicological evidence - GC-MS trace analysis in urine