Schoeller D A, Luke A H
Committee on Human Nutrition and Nutritional Biology, University of Chicago, Illinois 60637, USA.
J Mass Spectrom. 1997 Dec;32(12):1332-6. doi: 10.1002/(SICI)1096-9888(199712)32:12<1332::AID-JMS598>3.0.CO;2-E.
Continuous-flow isotope ratio mass spectrometry (CF-IRMS) has been shown to minimize sample preparation and reduce the sample size requirements and time for the determination of carbon and nitrogen. An inexpensive CF inlet was developed for the determination of the 18O isotopic abundance in CO2. Initial efforts were hampered by significant exchangeable oxygen within the inlet system, which was minimized by design changes and post-analysis mathematical correction. The system was tested for accuracy in the measurement of 18O abundance in standards and was accurate to 0.04/1000 with a precision of 0.03/1000. Additional tests were performed using urinary water for the measurement of energy expenditure by the doubly labeled water method and the results agreed to within 1% with those from traditional off-line, dual-inlet IRMS. The CF-IRMS reduced the analysis time to 2 min per sample compared with 15 min for traditional duel-inlet IRMS.
连续流同位素比率质谱法（CF - IRMS）已被证明可将样品制备降至最低，并减少测定碳和氮所需的样品量及时间。为测定二氧化碳中氧 - 18同位素丰度开发了一种廉价的连续流进样口。最初的工作受到进样系统内大量可交换氧的阻碍，通过设计变更和分析后数学校正将其降至最低。该系统在标准样品氧 - 18丰度测量中进行了准确性测试，准确度为0.04‰，精密度为0.03‰。使用尿水通过双标记水法测量能量消耗进行了额外测试，结果与传统离线双进样口IRMS的结果在1%以内相符。与传统双进样口IRMS每个样品15分钟的分析时间相比，CF - IRMS将分析时间缩短至每个样品2分钟。
