PMI R&D, Philip Morris Products S.A., Quai Jeanrenaud 5, CH-2000 Neuchâtel, Switzerland.
J Am Soc Mass Spectrom. 2024 Jun 5;35(6):1261-1271. doi: 10.1021/jasms.4c00062. Epub 2024 May 23.
We investigated the applicability of proton transfer reaction-time-of-flight mass spectrometry (PTR-TOF-MS) for quantitative analysis of mixtures comprising glycerin, acetol, glycidol, acetaldehyde, acetone, and propylene glycol. While PTR-TOF-MS offers real-time simultaneous determination, the method selectivity is limited when analyzing compounds with identical elemental compositions or when labile compounds present in the mixture produce fragments that generate overlapping ions with other matrix components. In this study, we observed significant fragmentation of glycerin, acetol, glycidol, and propylene glycol during protonation via hydronium ions (HO). Nevertheless, specific ions generated by glycerin (/ 93.055) and propylene glycol (/ 77.060) enabled their selective detection. To thoroughly investigate the selectivity of the method, various mixtures containing both isotope-labeled and unlabeled compounds were utilized. The experimental findings demonstrated that when samples contained high levels of glycerin, it was not feasible to perform time-resolved analysis in HO mode for acetaldehyde, acetol, and glycidol. To overcome the observed selectivity limitations associated with the HO reagent ions, alternative ionization modes were investigated. The ammonium ion mode proved appropriate for analyzing propylene glycol (/ 94.086) and acetone (/ 76.076) mixtures. Concerning the nitric oxide mode, specific / were identified for acetaldehyde (/ 43.018), acetone (/ 88.039), glycidol (/ 73.028), and propylene glycol (/ 75.044). It was concluded that considering the presence of multiple product ions and the potential influence of other compounds, it is crucial to conduct a thorough selectivity assessment when employing PTR-TOF-MS as the sole method for analyzing compounds in complex matrices of unknown composition.
我们研究了质子转移反应-飞行时间质谱（PTR-TOF-MS）在定量分析包含甘油、乙缩醛、缩水甘油、乙醛、丙酮和丙二醇的混合物中的适用性。虽然 PTR-TOF-MS 提供了实时同时测定，但当分析具有相同元素组成的化合物或混合物中不稳定的化合物产生与其他基质成分重叠的碎片离子时，该方法的选择性有限。在本研究中，我们观察到甘油、乙缩醛、缩水甘油和丙二醇在质子化过程中通过氢离子（HO）发生了显著的碎片化。然而，甘油（/ 93.055）和丙二醇（/ 77.060）产生的特定离子使其能够进行选择性检测。为了彻底研究该方法的选择性，使用了含有同位素标记和非标记化合物的各种混合物。实验结果表明，当样品中含有高浓度的甘油时，在 HO 模式下对乙醛、乙缩醛和缩水甘油进行时间分辨分析是不可行的。为了克服与 HO 试剂离子相关的观察到的选择性限制，研究了替代的电离模式。铵离子模式适用于分析丙二醇（/ 94.086）和丙酮（/ 76.076）混合物。关于一氧化氮模式，确定了乙醛（/ 43.018）、丙酮（/ 88.039）、缩水甘油（/ 73.028）和丙二醇（/ 75.044）的特定 /。得出的结论是，考虑到存在多个产物离子和其他化合物的潜在影响，在使用 PTR-TOF-MS 作为分析未知组成的复杂基质中化合物的唯一方法时，必须进行彻底的选择性评估。
