Koichi Tanaka Mass Spectrometry Research Laboratory , Shimadzu Corporation , 1 Nishinokyo-Kuwabaracho Nakagyo-ku , Kyoto 604-8511 , Japan.
Graduate School of Science and Engineering , Doshisha University , 1-3 Kyotanabe , Kyoto 610-0321 , Japan.
Anal Chem. 2018 Jun 19;90(12):7230-7238. doi: 10.1021/acs.analchem.8b00322. Epub 2018 Jun 5.
Gas-phase hydrogen radicals were introduced into a quadrupole ion trap containing singly charged phospholipids to obtain structural fragmentation patterns in tandem mass spectrometry (MS/MS). Saturated and unsaturated phosphatidylcholines were used as a model phospholipid, whose chain-length ranges between 16 and 24. The MS/MS spectrum yielded a continuous series of fragment ions with a mass difference of 14 Da, representing the saturated fatty acyl chains. The fragment ions corresponding to the double-bond position within a single fatty acyl chain showed a characteristic mass difference of 12 Da. The detection of these diagnostic product ions enabled the structural analysis of double-bond isomers of phospholipids. To further investigate the potential of radical-induced dissociation for the isomeric analysis of phospholipids, gas-phase hydroxyl radicals, and triplet oxygen atoms were employed in tandem mass spectrometry. The methylene bridges adjacent to the double-bond positions were selectively dissociated, accompanied by oxidation of the double bonds. Tandem mass spectrometry incorporating multiple radical species facilitates the structural analysis of isomeric phospholipids.
将气相氢自由基引入含有单电荷磷脂的四极离子阱中，以在串联质谱（MS/MS）中获得结构碎片化模式。饱和和不饱和磷脂酰胆碱被用作模型磷脂，其链长在 16 到 24 之间。MS/MS 谱产生了一系列具有 14 Da 质量差异的连续片段离子，代表饱和脂肪酸链。对应于单个脂肪酸链内双键位置的片段离子表现出 12 Da 的特征质量差异。这些诊断产物离子的检测能够实现磷脂双键异构体的结构分析。为了进一步研究自由基诱导解离在磷脂异构体分析中的潜力，气相羟基自由基和三重态氧原子被用于串联质谱。与双键位置相邻的亚甲基桥被选择性地解离，同时双键被氧化。结合多种自由基的串联质谱有助于异构磷脂的结构分析。
