PCs and SMs are the major types of glycerophospholipids and sphingophospholipids, the two main categories of phospholipids (PLs). To study the qualitative distribution of serum phosphatidylcholine (PC) and sphingomyelin (SM) in human and three rodent species, liquid chromatography-Orbitrap mass spectrometry (LC-Orbitrap-MS/MS) was used to identify them comprehensively through the accurate mass measurement of both precursor ions and their corresponding product ions. Based on the fragmentation rules of standards, the product ions at m/z 184.0733 were filtered to maximally screen possible PC and SM molecules. For PC, the fatty acid at sn-1 and sn-2 of the glycerol backbone was identified based on the product ions in negative mode. A total of 91 PCs and 31 SMs molecular species, consisting of 166 PCs and 39 SMs regioisomers, were detected in human serum, which is the most comprehensive identification of PC and SM species in serum. The qualitative distributions of PC in rat and SM in golden hamster, respectively, were more similar with that of human from an overall perspective. Those results provided guidance regarding to the animal model selection for mimicking lipid related-syndromes or diseases in human.

PC和SM是甘油磷脂和鞘磷脂的主要类型，这是磷脂（PL）的两个主要类别。为了研究人和三种啮齿动物中血清磷脂酰胆碱（PC）和鞘磷脂（SM）的定性分布，使用液相色谱-轨道分子质谱仪（LC-Orbitrap-MS / MS）通过对前体离子及其相应的产物离子。根据标准的碎裂规则，将m / z 184.0733处的产物离子过滤，以最大程度地筛选可能的PC和SM分子。对于PC，脂肪酸在sn -1和sn根据负离子下的产物离子鉴定出甘油主链上的-2。在人血清中共检测到91种PC和31种SM分子种类，其中包括166种PC和39种SM区域异构体，这是对血清PC和SM种类最全面的鉴定。从总体上看，大鼠中PC的定性分布和金仓鼠中SM的定性分布与人更相似。这些结果为模拟人脂质相关综合征或疾病的动物模型选择提供了指导。