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对3种极性头不同的磷脂DMPG、DMPC、DMPE的液相二次离子质谱分析中出现 的分子离子簇现象进行了系统的研究。结果表明，虽然分子离子簇的形成与许多因素有关， 如PH值、离子强度等，但起决定作用的是样品在底物中的浓度，浓度增大有利于分子离子簇 的形成。研究还发现，由不同种类磷脂分子形成的分子离子簇峰明显高于由同种磷脂分子所 形成的分子离子簇峰，指出异种磷脂分子间的簇离子形成能力高于同种磷脂分子。此外还讨 论了磷脂分子在离子源条件下的稳定性、裂解规律及相互作用等。结果表明，本实验所选用 的磷脂分子在LSIMS条件下是稳定的，均能得到较强的分子离子峰，其主要碎片峰是磷酰键断裂而产生的碎片离子峰。
The phenomenon of molecular ion clusters in liquid phase secondary ion mass spectrometry of three kinds of phospholipids DMPG, DMPC and DMPE with different polarity heads was systematically studied. The results show that although the molecular cluster formation depends on many factors, such as pH value and ionic strength, the concentration of the sample in the substrate is decisive. The increase of the concentration is conducive to the formation of molecular ion clusters. It was also found that the molecular cluster peaks formed by different types of phospholipid molecules were significantly higher than those formed by the same type of phospholipid molecules, indicating that cluster ion formation ability among different phospholipid molecules is higher than that of the same phospholipid molecules. In addition, the stability, cleavage rules and interaction of phospholipid molecules under ion source conditions are also discussed. The results showed that the phospholipid molecules selected in this experiment were stable under the condition of LSIMS, and all the strong molecular ion peaks were obtained. The main fragment peak was the fragment ion peak resulting from the cleavage of phosphoryl bond.