Toxicology and Forensic Chemistry Unit, University Center of Legal Medicine Lausanne-Geneva,Lausanne, Switzerland.
Anal Chim Acta. 2013 Jun 19;784:42-6. doi: 10.1016/j.aca.2013.04.046. Epub 2013 May 1.
A novel approach to measure carbon dioxide (CO2) in gaseous samples, based on a precise and accurate quantification by (13)CO2 internal standard generated in situ is presented. The main goal of this study was to provide an innovative headspace-gas chromatography-mass spectrometry (HS-GC-MS) method applicable in the routine determination of CO2. The main drawback of the GC methods discussed in the literature for CO2 measurement is the lack of a specific internal standard necessary to perform quantification. CO2 measurement is still quantified by external calibration without taking into account analytical problems which can often occur considering gaseous samples. To avoid the manipulation of a stable isotope-labeled gas, we have chosen to generate in situ an internal labeled standard gas ((13)CO2) on the basis of the stoichiometric formation of CO2 by the reaction of hydrochloric acid (HCl) with sodium hydrogen carbonate (NaH(13)CO3). This method allows a precise measurement of CO2 concentration and was validated on various human postmortem gas samples in order to study its efficiency.
本文提出了一种基于（13）CO2 内标原位生成的精确、准确定量测量气态样品中二氧化碳（CO2）的新方法。本研究的主要目的是提供一种创新的顶空气相色谱-质谱（HS-GC-MS）方法，适用于 CO2 的常规测定。文献中讨论的用于 CO2 测量的 GC 方法的主要缺点是缺乏进行定量所需的特定内标。CO2 的测量仍然通过外部校准进行定量，而没有考虑到经常出现在气态样品中的分析问题。为了避免对稳定同位素标记气体的操作，我们选择基于盐酸（HCl）与碳酸氢钠（NaH（13）CO3）反应生成的 CO2 的化学计量形成，在现场生成内部标记标准气体（（13）CO2）。该方法可实现 CO2 浓度的精确测量，并已在各种人体死后气体样品上进行了验证，以研究其效率。
