Manz Christian, Grabarics Márkó, Hoberg Friederike, Pugini Michele, Stuckmann Alexandra, Struwe Weston B, Pagel Kevin
Institute of Chemistry and Biochemistry, Freie Universität Berlin, Takustrasse 3, 14195 Berlin, Germany.
Fritz Haber Institute of the Max Planck Society, Department of Molecular Physics, Faradayweg 4-6, 14195 Berlin, Germany.
Analyst. 2019 Sep 7;144(17):5292-5298. doi: 10.1039/c9an00937j. Epub 2019 Aug 5.
The analysis of complex oligosaccharides is traditionally based on multidimensional workflows where liquid chromatography is coupled to tandem mass spectrometry (LC-MS/MS). Due to the presence of multiple isomers, which cannot be distinguished easily using tandem MS, a detailed structural elucidation is still challenging in many cases. Recently, ion mobility spectrometry (IMS) showed great potential as an additional structural parameter in glycan analysis. While the time-scale of the IMS separation is fully compatible to that of LC-MS-based workflows, there are very few reports in which both techniques have been directly coupled for glycan analysis. As a result, there is little knowledge on how the derivatization with fluorescent labels as common in glycan LC-MS affects the mobility and, as a result, the selectivity of IMS separations. Here, we address this problem by systematically analyzing six isomeric glycans derivatized with the most common fluorescent tags using ion mobility spectrometry. We report >150 collision cross-sections (CCS) acquired in positive and negative ion mode and compare the quality of the separation for each derivatization strategy. Our results show that isomer separation strongly depends on the chosen label, as well as on the type of adduct ion. In some cases, fluorescent labels significantly enhance peak-to-peak resolution which can help to distinguish isomeric species.
复杂寡糖的分析传统上基于多维工作流程，其中液相色谱与串联质谱（LC-MS/MS）联用。由于存在多种异构体，使用串联质谱难以轻松区分，因此在许多情况下，详细的结构解析仍然具有挑战性。最近，离子淌度光谱法（IMS）在聚糖分析中作为一种额外的结构参数显示出巨大潜力。虽然IMS分离的时间尺度与基于LC-MS的工作流程完全兼容，但很少有报告将这两种技术直接联用进行聚糖分析。因此，对于聚糖LC-MS中常见的荧光标记衍生化如何影响淌度以及IMS分离的选择性，人们了解甚少。在这里，我们通过使用离子淌度光谱法系统分析六种用最常见荧光标签衍生化的异构聚糖来解决这个问题。我们报告了在正离子和负离子模式下获得的超过150个碰撞截面（CCS），并比较了每种衍生化策略的分离质量。我们的结果表明，异构体分离强烈依赖于所选的标签以及加合离子的类型。在某些情况下，荧光标签显著提高了峰间分辨率，这有助于区分异构物种。
