琼胶寡糖的ESI-MS分析研究

ESI-MS spectroscopy investigation of agarose-oligosaccharides

首次对 6种琼胶寡糖的分子量 ,采用电喷雾电离质谱 (ESI -MS)进行分析测定。结果表明 ,琼胶寡糖的ESI -MS谱图非常清晰 ,能准确判断出琼胶寡糖的分子量。这些寡糖只出现 [M +Na]+ 加成离子 ,而不出现 [M + 1]+ 的准分子离子 ,且 [M +Na]+ 分子离子峰均特强 ;同时还出现一系列 [M + 2Na]+ 的加成离子。当化合物分子量大于 10 0 0时 ,则给出双电荷离子 ;当化合物分子量小于 10 0 0时 ,则ESI -MS谱出现[2M +Na]+ 的系列离子。实验结果揭示 ,所得 6种琼胶寡糖的分子量分别为 32 4、630、936、12 4 2、15 48和185 4。

The agarose was digested by agarose enzyme, and 6 kinds of agarose-oligosaccharides were obtained. Using ESI-MS to analyze them, the spectra was very clear and the molecular weight of those oligosaccharides could be accurately determined to be 324, 630, 936, 1 242, 1 548 and 1 854, respectively. The ESI-MS spectra indicated the presence of stronger addition ion + and the absence of quasi-molecular ion +. At the same time, there were addition ion in the ESI-MS spectra. The ESI-MS spectra shew double charge ion when the molecular weight of oligomers was more than 1 000 and the series ion + when the molecular weight less than 1 000. The 6 oligosaccharides were bio-, tetra-, hexa-, octa-, deca- and dodeca-saccharide, respectively.