Department of Biosurgery and Surgical Technology, Imperial College London, St. Mary's Hospital, London, United Kingdom.
J Am Soc Mass Spectrom. 2010 Jun;21(6):1070-4. doi: 10.1016/j.jasms.2010.02.008. Epub 2010 Feb 10.
Selected ion flow tube mass spectrometry, SIFT-MS, has been used to determine the repeatability of the analysis of volatile metabolites within the breath of healthy volunteers, with emphasis on the influence of sampling methodology. Baseline instrument specific coefficients of variability for examined metabolites were as follows: acetone (1%), ammonia (1%), isoprene (2%), propanol (6%), ethanol (7%), acetic acid (7%), and hydrogen cyanide (19%). Metabolite concentration and related product ion count rate were identified as strong determinants of measurement variation. With the exception of ammonia, an orally released metabolite, variability in repeated on-line breath analysis tended to be lower for metabolites of systemic origin. Standardization of sampling technique improved the repeatability of the analysis of selected metabolites. Off-line (bag) alveolar breath sampling, as opposed to mixed (whole) breath sampling, likewise improved the repeatability of the analysis of all metabolites investigated, with the exception of acetic acid. We conclude that SIFT-MS analysis of common volatile metabolites within the breath of healthy volunteers is both reliable and repeatable. For selected metabolites, the finding that repeatability is improved through modification of sampling methodology may have implications in terms of future recommended practices.
选择离子流管质谱法（SIFT-MS）已被用于确定健康志愿者呼吸中挥发性代谢物分析的可重复性，重点关注采样方法的影响。检查代谢物的仪器特定基线变异系数如下：丙酮（1%）、氨（1%）、异戊二烯（2%）、丙醇（6%）、乙醇（7%）、乙酸（7%）和氢氰酸（19%）。代谢物浓度和相关产物离子计数率被确定为测量变异的强决定因素。除了氨（一种口服释放的代谢物）之外，系统来源的代谢物的在线重复呼吸分析中的变异性往往较低。采样技术的标准化提高了选定代谢物分析的可重复性。与混合（全）呼吸采样相比，离线（袋）肺泡呼吸采样同样提高了所有研究代谢物分析的可重复性，除了乙酸。我们得出结论，SIFT-MS 分析健康志愿者呼吸中的常见挥发性代谢物既可靠又可重复。对于选定的代谢物，通过修改采样方法提高可重复性的发现可能对未来推荐的实践产生影响。
