Okamoto M, Takahashi K, Doi T, Takimoto Y
Environmental Health Science Laboratory, Sumitomo Chemical Company, Ltd., Osaka, Japan.
Anal Chem. 1997 Aug 1;69(15):2919-26. doi: 10.1021/ac960910s.
The sensitivities of oligosaccharide derivatives in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) were compared using two matrixes, 2,5-dihydroxybenzoic acid (DHBA) and alpha-cyano-4-hydroxycinnamic acid (CHCA). For this purpose, maltopentaose was tagged with 2-aminopyridine (PA), 4-aminobenzoic acid ethyl ester (ABEE), and trimethyl-(p-aminophenyl)ammonium chloride (TMAPA). DHBA was more advantageous for enhancement than CHCA. Among the derivatives, the sensitivity with the PA-tagged maltopentaose showed a 100-fold improvement over the native one with DHBA as a matrix, while the oligesaccharide derivatized with ABEE and TMAPA gave 30- and 10-fold increases in sensitivity over the underivatized one. To obtain structural information from these derivatized oligosaccharides, postsource decay (PSD) during flight in the field-free drift in MALDI-TOFMS was measured. Predictable and reproducible fragmentation patterns could be obtained in all cases. Furthermore, we found matrix-dependence fragmentation with the PA-labeled oligosaccharide. With CHCA, a simple spectrum ascribable to Y series ions was obtained. On the other hand, both B and Y series ions were clearly observed in the DHBA case. The results demonstrate the usefulness of derivatives for sensitive analysis of oligosaccharides with MALDI.
使用两种基质，即2,5-二羟基苯甲酸（DHBA）和α-氰基-4-羟基肉桂酸（CHCA），比较了寡糖衍生物在基质辅助激光解吸/电离飞行时间质谱（MALDI-TOFMS）中的灵敏度。为此，用2-氨基吡啶（PA）、4-氨基苯甲酸乙酯（ABEE）和三甲基-（对氨基苯基）氯化铵（TMAPA）标记麦芽五糖。DHBA在增强效果方面比CHCA更具优势。在这些衍生物中，以PA标记的麦芽芽五糖的灵敏度与以DHBA为基质的天然麦芽五糖相比提高了100倍，而用ABEE和TMAPA衍生化的寡糖比未衍生化的寡糖灵敏度分别提高了30倍和10倍。为了从这些衍生化的寡糖中获得结构信息，测量了MALDI-TOFMS中无场漂移飞行期间的源后衰变（PSD）。在所有情况下都可以获得可预测和可重复的碎裂模式。此外，我们发现了PA标记的寡糖的基质依赖性碎裂。使用CHCA时，获得了一个可归因于Y系列离子的简单光谱。另一方面，在DHBA的情况下，B系列和Y系列离子都清晰可见。结果证明了这些衍生物对于用MALDI对寡糖进行灵敏分析的有用性。
