Department of Chemistry, Center for Innovative Technology, Vanderbilt Institute of Chemical Biology, Vanderbilt Institute for Integrative Biosystems Research and Education, Vanderbilt University , Nashville, Tennessee 37235, United States.
Anal Chem. 2017 Jan 3;89(1):952-959. doi: 10.1021/acs.analchem.6b04171. Epub 2016 Dec 21.
In this study we investigated 11 isomers with the molecular formula CHNO (m/z 131) to ascertain the potential of utilizing drift tube ion mobility mass spectrometry to aid in the separation of isomeric mixtures. This study of small molecules provides a detailed examination of the application of uniform field ion mobility for a narrow scope of isomers with variations in both bond coordination and stereochemistry. For small molecules, it was observed that in general constitutional isomers are more readily separated by uniform field mobility in comparison to stereoisomers such as enantiomers or diastereomers. Diastereomers exhibited differences in their collision cross section (CCS), but were unresolvable in a mixture, whereas the enantiomers studied did not exhibit statistically different CCS values. A mathematical relationship relating the CCS to resolving power was developed in order to predict the required ion mobility resolving power needed to separate the various isomer classes. For the majority of isomers evaluated in this study, a uniform field-based resolving power of 100 was predicted to be sufficient to resolve over half (∼60%) of all hypothetical isomer pairs, including leucine and isoleucine, whereas their stereoisomers (d- and l-forms) are predicted to be significantly more challenging, if not impossible, to separate by conventional drift tube techniques.
在这项研究中，我们研究了 11 种具有化学式 CHNO（m/z 131）的异构体，以确定利用漂移管离子迁移质谱来帮助分离异构体混合物的潜力。这项对小分子的研究详细考察了均匀场离子迁移在广泛的具有不同键协调和立体化学的异构体范围内的应用。对于小分子，观察到一般情况下，与对映异构体或非对映异构体等立体异构体相比，构象异构体更容易通过均匀场迁移来分离。非对映异构体的碰撞截面（CCS）存在差异，但在混合物中无法分辨，而所研究的对映异构体则没有表现出统计学上不同的 CCS 值。为了预测分离各种异构体所需的离子迁移分辨率，开发了一种将 CCS 与分辨率相关联的数学关系。对于本研究中评估的大多数异构体，预计基于均匀场的分辨率为 100 足以分离超过一半（约 60%）的所有假设异构体对，包括亮氨酸和异亮氨酸，而它们的立体异构体（d-和 l-形式）则预计通过传统的漂移管技术进行分离将极具挑战性，如果不是不可能的话。
