TANDEM QUADRUPOLE MASS SPECTROMETRY OF SPHINGOMYELIN

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 低能碰撞激活解离(CAD)串联四极杆和电喷雾电离多级离子陷阱(IT)质谱仪为鞘磷脂的完整结构表征提供了灵敏的方法。当受到电喷雾电离(ESI)时，在碱金属离子存在的情况下，鞘磷脂容易形成丰富的[M+Cat]+离子(Cat=Li、Na或K)。在低能量CAD之后，鞘磷脂的[M+Li]+离子产生丰富的碎片离子，识别分子的脂肪酰基成分和长链碱基。具有前驱体离子或恒定中性损失扫描的串联四极杆质谱仪有助于识别特定的鞘磷脂亚类，这些亚类随长链碱基或脂肪酸取代基的不同而变化。另一方面，多阶段IT质谱学提供了一个强大的工具，可以深入了解裂解过程的潜在机制，并使用鞘磷脂的MS5谱进行结构表征。还介绍了串联四极杆和多级IT质谱学在区分鞘磷脂异构体方面的应用。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Low-energy collisionally activated dissociation (CAD) tandem quadrupole and multiple-stage ion-trap (IT) mass spectrometry with electrospray ionization provide sensitive methods for complete structural characterization of sphingomyelin. Sphingomyelin readily forms abundant [M + Cat]+ ions (where Cat = Li, Na, or K) in the presence of alkali metal ion, when being subjected to electrospray ionization (ESI). Following low-energy CAD, the [M + Li]+ ions of sphingomyelin yield abundant fragment ions that identify both the fatty acyl constituent and the long-chain base of the molecule. Tandem quadrupole mass spectrometry with precursor ion or constant neutral loss scans facilitates identification of specific sphingomyelin subclasses that are varied by the long-chain base, or by the fatty acid substituents. The multiple-stage IT mass spectrometry, on the other hand, provides a powerful tool to get insight into the mechanisms underlying the fragmentation processes, and to perform structural characterization using the MS5-spectra for sphingomyelins. The applications of tandem quadrupole and multiple-stage IT mass spectrometry for differentiation among sphingomyelin isomers are also presented.