The detection and quantitation of 7-aminoflunitrazepam, the major urinary metabolite of flunitrazepam, by gas chromatography/mass spectrometry

A sensitive gas chromatography/mass spectrometry method for the detection a nd quantitation of 7-aminoflunitrazepam, the major urinary metabolite of fl unitrazepam, is described. The method is based upon solvent extraction foll owed by derivatisation with methyl-bis-trifluoroacetamide (MBTFA), to give a trifluoroacetyl derivative. A profile of 7-aminoflunitrazepam urinary con centrations following ingestion of 0.5 to 4 mg oral doses is reported. The method has been found to be reproducible and can be used for the confirmati on of flunitrazepam administration.