Abstract: A method was developed for the determination of urinary 7-aminonitrazepam(7-ANZP),the major metabolite of nitrazepam,by high performance liquid chromatography-electrospray tandem mass spectrometry. After being added 7-aminoclonazepam(7-ACZP,internal standard),hydrolyzed with β-glucuronidase,liquid-liquid extracted at pH 10.8,and filtrated with 0. 45 μm membrane,the samples were analyzed. Mass spectral acquisition was performed with selective reaction monitoring of two diagnostic transition reactions. The qualitative analysis was based on the retention time,and the quantification was carried out with intension of the internal standard. The recoveries of 7-ANZP in spiked blank samples at different concentration levels are in the range of 89.0%～95.2% with relative standard deviations(RSD) no more than 6.4%. The limit of detection in urine(LOD) is 0.07 μg/L,and the limit of quantification(LOQ) is 0.5μg/L. The linear range is from 1μg/L to 50μg/L. This method is suitable for analysis of 7-ANZP with characteristics of easy operating,high sensitivity and repeatability.

Key words: high performance liquid chromatography, electrospray tandem mass spectrometry, nitrazepam, 7-aminonitrazepam