The Stereochemical Dependence of Unimolecular Dissociation of Monosaccharide-Glycolaldehyde Anions in the Gas Phase: A Basis for Assignment of the Stereochemistry and Anomeric Configuration of Monosaccharides in Oligosaccharides by Mass Spectrometry via a Key Discriminatory Product Ion of Disaccharide Fragmentation, <i>m</i>/<i>z</i> 221
作者:Tammy T. Fang、Brad Bendiak
DOI:10.1021/ja0717313
日期:2007.8.1
stereochemistry and anomeric configuration, for all 16 stereochemical variants. The ions were shown to be glycopyranosyl-glycolaldehydes through chemical synthesis of their standards. The stereochemistry dramatically affected fragmentation which was dependent on four relative stereochemical arrangements: (1) the relationship between the hydroxyl group at position 2 and the anomeric configuration, (2) a cis relationship
含己糖二糖的质谱分析通常会在负离子模式下产生 m/z 221 的产物离子。使用 Paul 阱,m/z 221 阴离子的分离和碰撞诱导解离产生的质谱图可以轻松区分所有 16 种立体化学变体的立体化学和异头构型。通过标准品的化学合成,这些离子被证明是吡喃糖基乙醇醛。立体化学显着影响碎片化,这取决于四种相对立体化学排列:(1) 2 位羟基与异头构型之间的关系,(2) 异头位置与 2 和 3 位的顺式关系 (1,2 ,3-cis), (3) 1,2 trans-2,3 cis 关系,(4) 4位羟基与异头构型的关系。在用 18O 标记一系列二糖的还原羰基氧以区分它们的单糖成分后,证明 m/z 221 阴离子由一个完整的非还原糖组成,糖苷键连接到来自还原反应的 2-碳苷元糖,与单糖之间的连接位置无关。这使得完整糖的位置能够被分配到糖苷键的非还原侧。对重现性所需的实验因素的详细研究表明,每个 m/z 221