TLC & MALDI FT ICR MS & SORI CID ANALYSIS OF GLYCOSPHINGOLIPIDS

碳水化合物的结构多样性及其关键作用 在许多生物学功能中， 他们的技术特点。 串联质谱法具有 已经被证明是一个强大的手段， 序列、分支和糖苷间键 衍生聚糖。 全甲基化低聚糖已被 通过基质辅助激光解吸/电离（MALDI）分析， 源后衰变中的反射飞行时间质谱仪 (PSD)模式 一系列全甲基化 低聚糖已经进行了制定的理由， 碎片化过程。 经钠化或还原的化合物的PSD质谱 锂化分子物种显示强烈的信号，反映了 优先裂解N-乙酰己糖胺上的糖苷键 残基 这些片段允许立即鉴定HexNAc 单位及其在糖序列中的位置。 更多的基因反弹， 糖苷键的裂解产生了带有 寡糖的还原或非还原末端，从而允许 序列分配和分支。 3位糖基化 HexNAc残基导致高度特异性的片段化过程 包括消除这些取代基，从而允许 这种类型的糖苷间键的明确分配。 出现全甲基化寡糖的MALDI-PSD质谱 作为技术的有价值的补充（和/或替代） 目前用于碳水化合物结构分析。

The structural diversity of carbohydrates and their crucial role in many biological functions has prompted the development of new techniques for their characterization. Tandem mass spectrometry has been shown to be a powerful means of getting structural information on sequence, branching and interglycosidic linkages in native or derivatized glycans. Permethylated oligosaccharides have been analyzed by matrix-assisted laser desorption/ ionization (MALDI) using a reflectron time-of-flight mass spectrometer in the post-source decay (PSD) mode. A systematic study of a series of permethylated oligosaccharides has been carried out to formulate a rationale for the fragmentation processes. PSD mass spectra of the sodiated or lithiated molecular species showed intense signals reflecting the preferential cleavage of the glycosidic bonds at N-acetylhexosamine residues. These fragments allow immediate identification of HexNAc units and their location within the sugar sequence. More gene rally, cleavage of the glycosidic bonds yielded fragments bearing either the reducing or nonreducing end of the oligosaccharide, thus allowing assignment of sequence and branching. Glycosylation at position 3 of HexNAc residues led to a highly specific fragmentation process involving the elimination of these substituents and thus allowed unambiguous assignment of this type of interglycosidic linkage. MALDI-PSD mass spectrometry of permethylated oligosaccharides appears to be a valuable complement (and/or alternative) to the techniques currently in use for carbohydrate structural analysis.