Tobacco and Volatiles Branch, Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA, USA.
J Anal Toxicol. 2013 May;37(4):195-202. doi: 10.1093/jat/bkt020. Epub 2013 Mar 18.
A sensitive and selective method was developed and validated to detect six volatile nitrosamines (N-nitrosodimethylamine, N-nitrosomethylethylamine, N-nitrosodiethylamine, N-nitrosopiperidine, N-nitrosopyrrolidine and N-nitrosomorpholine) in human urine. This method uses a liquid-liquid extraction cartridge followed by analysis with gas chromatography-tandem mass spectrometry (GC-MS-MS) and quantification based on isotopic dilution. This is the first GC-MS-MS method reported for measuring volatile nitrosamines in human urine. This method reduces the sample volume required in other methods from 5-25 to 2 mL. The limits of detection (2.62, 1.99, 2.73, 0.65, 0.25, 3.66 pg/mL, respectively) were better than existing methods, largely because of improved positive chemical ionization achieved by using ammonia gas and reducing background noise. Using nitrogen as the collision gas allowed the confirmation transition in the low mass region to be monitored. The analysis of human urine using this validated method is accurate (relative bias of 0-19%) and precise (relative standard deviation of 0.2-18% over two months of analyses). The validated method was applied to 100 urine samples and the levels of all six volatile nitrosamines were reported for the first time in urine specimens collected from smokers and nonsmokers, with smoking status determined by urinary cotinine measurement. Among 100 smokers and nonsmokers, the levels of three analytes (N-nitrosodimethylamine, N-nitrosomethylethylamine and N-nitrosopiperidine) were significantly higher in smokers than nonsmokers (p < 0.05).
建立并验证了一种灵敏、选择性的方法，用于检测人尿中的六种挥发性亚硝胺（N-亚硝基二甲胺、N-亚硝基甲乙胺、N-亚硝基二乙胺、N-亚硝基哌啶、N-亚硝基吡咯烷和 N-亚硝基吗啉）。该方法使用液液萃取柱，然后用气相色谱-串联质谱（GC-MS-MS）进行分析，并基于同位素稀释进行定量。这是首个报道的用于测量人尿中挥发性亚硝胺的 GC-MS-MS 方法。与其他方法相比，该方法将所需的样品体积从 5-25 减少到 2 毫升。检测限（分别为 2.62、1.99、2.73、0.65、0.25 和 3.66pg/mL）优于现有方法，主要是因为使用氨气提高了正化学电离，并降低了背景噪声。使用氮气作为碰撞气体，可以监测低质量区域的确认跃迁。使用该验证方法分析人尿，结果准确（相对偏差为 0-19%），且精确（两个月的分析中相对标准偏差为 0.2-18%）。该验证方法应用于 100 个尿样，首次报告了吸烟和不吸烟者尿样中六种挥发性亚硝胺的水平，吸烟状况通过尿可替宁测量确定。在 100 名吸烟者和不吸烟者中，三种分析物（N-亚硝基二甲胺、N-亚硝基甲乙胺和 N-亚硝基哌啶）的水平在吸烟者中明显高于不吸烟者（p<0.05）。
