Central Analytical Research Facility, Queensland University of Technology , Brisbane, Queensland 4001, Australia.
School of Chemistry, University of Wollongong , Wollongong, New South Wales 2522, Australia.
Anal Chem. 2016 Mar 1;88(5):2685-92. doi: 10.1021/acs.analchem.5b04001. Epub 2016 Feb 8.
Unambiguous identification of isomeric lipids by mass spectrometry represents a significant analytical challenge in contemporary lipidomics. Herein, the combination of collision-induced dissociation (CID) with ozone-induced dissociation (OzID) on an ion-trap mass spectrometer is applied to the identification of triacylglycerol (TG) isomers that vary only by the substitution pattern of fatty acyl (FA) chains esterified to the glycerol backbone. Isolated product ions attributed to loss of a single FA arising from CID of TG + Na ions react rapidly with ozone within the ion trap. The resulting CID/OzID spectra exhibit abundant ions that unequivocally reveal the relative position of FAs along the backbone. Isomeric TGs containing two or three different FA substituents are readily differentiated by diagnostic ions present in their CID/OzID spectra. Compatibility of this method with chromatographic separations enables the characterization of unusual TGs containing multiple short-chain FAs present in Drosophila.
质谱法对具有立体异构的脂质进行明确鉴定是当代脂质组学面临的重大分析挑战。在此，在离子阱质谱仪上，采用碰撞诱导解离（CID）与臭氧诱导解离（OzID）相结合的方法，对甘油骨架酯化的脂肪酸（FA）链取代模式仅略有不同的三酰基甘油（TG）异构体进行鉴定。CID 产生的[TG+Na]+离子中，单个 FA 缺失产生的特征产物离子与离子阱中的臭氧迅速反应。所得 CID/OzID 谱显示出丰富的离子，这些离子可明确揭示 FA 在骨架上的相对位置。CID/OzID 谱中存在的特征离子可轻松区分含有两个或三个不同 FA 取代基的 TG 异构体。该方法与色谱分离的兼容性可用于鉴定果蝇中存在的含有多个短链 FA 的异常 TG。
