Ion mobility-mass spectrometry (IM-MS) is a combination of ion mobility separation and mass spectrometry technologies. In IM-MS, analytes are ionized by the ion source to form gas-phase ions, which are then rapidly separated using ion mobility based on their mobility difference, under the influence of both neutral buffer gas and an electric field, and then traversed and detected using mass spectrometry, which can separate ions based on mass-to-charge ratio. Furthermore, IM-MS could provide not only mass-to-charge ratio parameters like MS1 and MS2 spectra but also new structural information for component identification like collision cross-section values, drift time, arrival time, compensation voltage, and so on, which can be employed to resolve complex chemical components, especially indistinguishable isomers using mass spectrometry alone. In recent years, with the development of IM-MS technologies, IM-MS has become more widely employed in chemical analysis in traditional Chinese medicines (TCMs). Firstly, IM-MS was been successfully used in the separation of complex TCMs complex extract from interfering isobaric species. Secondly, IM-MS also offers new types of MS/MS fragmentation modes, and the combination of IM separation and fragmentation modes enables the acquisition of more specific and detailed fragment ion spectra. Thirdly, the collision cross-section is introduced by IM-MS, which is a unique physicochemical property of a component. Related data post-processing strategies based on experimentally derived collision cross-section values have been continuously developed in recent years to make full use of the collision cross-section values, these data post-processing strategies include collision cross-section database matching, theoretical collision cross-section values matching, machine-learning-based collision cross-section values prediction matching, mass-to-charge ratio versus collision cross-section correlation trend lines and so on. In doing so, these diverse strategies can greatly enhance the reliability and accuracy of the structural annotation of TCM compounds. This review primarily briefly introduces the major types and basic principles of IM-MS. The applications of IM-MS in TCM chemical analysis are highlighted in this study. The current applications of IM-MS in improving TCM chemical component separation are summarized, followed by a discussion of several strategies for enhancing separation selectivity. This review also offers some new fragmentation modes, novel data acquisition approaches, and collision cross-section data post-processing strategies applied in TCM qualitative analysis. Finally, the prospect of IM-MS applied in TCM chemical analysis is also discussed. This review provides approaches and ideas for future IM-MS research on TCM's chemical analysis.
离子淌度质谱(IM-MS)是一种将离子淌度分离与质谱分析相结合的新型分析技术。IM-MS的主要优势不仅是在质谱检测前提供了基于气相离子形状、大小、电荷数等因素的多一维分离,而且能够提供碰撞截面积、漂移时间等质谱信息进而辅助化合物鉴定。近年来,随着IM-MS技术的不断发展,该技术在中药化学成分分析中受到越来越多的关注。首先,IM-MS已成功应用于改善中药复杂成分尤其是同分异构体或等量异位素等成分的分离;其次,IM-MS可通过多重碎裂模式辅助高质量中药小分子质谱信息的获取;此外,IM-MS提供的高维质谱数据信息还可促进中药复杂体系多成分的整合分析。该文在对IM-MS分类和基本原理进行概述的基础上,从分离能力及分离策略、多重碎裂模式、多维质谱数据处理策略3个方面,重点综述了IM-MS在中药化学成分分析中的应用,以期为IM-MS在中药化学成分研究提供参考。
Keywords: chemical components; ion mobility-mass spectrometry (IM-MS); review; traditional Chinese medicines (TCMs).