DELAYED EXTRACTION ON VISION 2000 REFLECTRON TIME OF FLIGHT MASS SPECTROMETER

ESI-三重四极串联质谱仪(MS/MS) 以前应用于糖苷链指认 过甲基化与碱金属阳离子结合的碳水化合物 正模电离中的内收，并提供了 敏感性和广泛的糖苷特征。然而， 链接标识通常会因存在 N-乙酰化氨基糖或唾液酸，并通过增加分子 大小，倾向于促进糖苷碎裂的因素 连锁识别所需的开环路径。上一首 研究人员以负模式指定了二糖中的键 电离和低能量碰撞。在本研究中，连锁分析 负模电喷雾电离(ESI)和三重四极 MS/MS被扩展到更大的寡糖。连锁鉴定 从减少端通过特定的消除而获得的收益。尽管 不需要去质子化的初始位置来进行还原 低聚糖无游离基的末端糖苷键 还原终点一般不能确定。

ESI-triple quadrupole tandem mass spectrometry (MS/MS) has previously been applied to glycosidic linkage assignment in carbohydrates by combining permethylation with alkali metal cation adduction in positive mode ionization and has provided both sensitivity and extensive glycosidic characterization. However, the linkage identification is often compromised by the presence of N-acetylated amino sugars or sialic acids and by increasing molecular size, factors which tend to promote glycosidic fragmentation over the ring-opening pathways required for linkage identification. Previous investigators have assigned linkages in disaccharides by negative mode ionization and low energy collisions. In this study, linkage analysis by negative mode electrospray ionization (ESI) and triple quadrupole MS/MS is extended to larger oligosaccharides. Linkage identification proceeds by specific eliminations from the reducing end. Although the initial site of deprotonation is not required to b e the reducing terminal, glycosidic linkages of oligosaccharides without a free reducing end cannot generally be determined.