Charge Distribution between Different Classes of Glycerophospolipids in MALDI-MS Imaging
Charge Distribution between Different Classes of Glycerophospolipids in MALDI-MS Imaging
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DOI：
10.1021/acs.analchem.9b05761
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发表时间：
2020-04-07
影响因子：
7.4
通讯作者：
Soltwisch, Jens
中科院分区：
文献类型：
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作者：
Boskamp, Marcel S.;Soltwisch, Jens
基质辅助激光解吸电离质谱成像 (MALDI-MSI) 在越来越多的应用中被广泛用于可视化和分析膜脂的分布。在这种情况下，甘油磷脂（GPL）的不同脂型是人们感兴趣的主要目标之一。然而，对于这组分析物，离子抑制效应被描述为比其他类别更有利于某些 GPL 类别的检测，从而阻碍了受抑制物质的分析并极大地限制了定量分析。这些效应通常归因于 MALDI 过程中可用电荷载流子的分布。在这里，我们对 MALDI-MSI 条件下不同类别 GPL 之间的电荷分布进行了系统研究。为此，我们构建了具有不同配方脂质成分的人造组织阵列，其中仅包含预定义量的两种特定 GPL 类别，并在正离子和负离子模式下使用 MALDI-MSI 对其进行分析。除了预期离子抑制效应的表征之外，对这些二元系统的分析揭示了某些 GPL 类别的组合的尚未描述的信号强度增强。此外，综合数据使我们能够为所研究的 GPL 类别在两种极性下编制电荷亲和力层次结构。其他实验表明，激光后电离 (MALDI-2) 具有巨大的潜力，可以覆盖标准 MALDI-MSI 中观察到的不同 GPL 类别之间的电荷分布引起的信号强度变化。
Matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) is widely used to visualize and analyze the distribution of membrane lipids in an increasingly large number of applications. In this context, different lipoforms of glycerophospholipids (GPLs) are among the prime targets of interest. For this group of analytes, however, ion suppression effects have been described to strongly favor the detection of certain GPL classes over others, thereby hampering the analysis of suppressed species and greatly restraining quantitative analysis. These effects are generally attributed to the distribution of available charge carriers during the MALDI process. Here, we present a systematic investigation of charge distribution between different classes of GPL under MALDI-MSI conditions. For this, we constructed arrays of artificial tissues with different formulated lipid composition that contained predefined amounts of only two specific GPL classes and analyzed them with MALDI-MSI in positive- and negative-ion modes. Next to a characterization of expected ion suppression effects, analysis of these binary systems revealed yet undescribed signal intensity enhancement for the combinations of certain GPL classes. Furthermore, the comprehensive data allowed us to compile a hierarchy of charge affinities for the investigated GPL classes in both polarities. Additional experiments revealed that laser post-ionization (MALDI-2) has great potential to overwrite changes in signal intensity caused by charge distribution among different GPL classes observed in standard MALDI-MSI.