We have prepared a number of isomeric red seaweed galactan-derivative sulfated oligosaccharides to determine whether there were diagnostic differences among the isomeric mass spectra obtained using ESI CID MS/MS (triple quadrupole instrument). Fragmentation of the single or multicharged molecular ions from di-, tetra-, and hexasaccharides indicated that the relative positioning of the sulfate groups and type of monosaccharide unit affect the rate of cleavage of the glycosidic bonds. We also performed a comparative [M-Na]⁻ fragmentation study of positional isomers of sulfated disaccharides that present all four monosulfation possibilities on the galactopyranosidic ring. In this case, negative-ion ESI CID MS/MS approach gave diagnostic product ions from cross-ring cleavages along with the same main B₁ ion (from sulfated Gal_p), at m/z 241, for all isomers. The isomeric disaccharides were also submitted to increased spray energy conditions inducing in-source fragmentation; preformed B₁ ions were then fragmented to give similar product ions as those found in [M-Na]⁻ analysis. Evaluation of the relative abundances mainly for cross-ring fragment ions at m/z 138, 139, 151, 153 allowed clear distinction among the members of the disaccharide series. The different ratios for m/z 151/153 ions were consistent with the predominance of m/z 153 being related to the cases when the bond involved in the cleavage process links a sulfated carbon. A quadrupole ion trap instrument (MSⁿ analysis) was also utilized to compare the results obtained with the triple quadrupole instrument.

我们制备了许多异构的红海藻半乳聚糖衍生物硫酸化寡糖，以确定使用 ESI CID MS/MS（三重四极杆仪器）获得的异构质谱之间是否存在诊断差异。来自二糖、四糖和六糖的单电荷或多电荷分子离子的断裂表明硫酸盐基团的相对位置和单糖单元的类型影响糖苷键的裂解速率。我们还对在吡喃半乳糖苷环上呈现所有四种单硫酸化可能性的硫酸化二糖的位置异构体进行了比较 [M-Na] ^-断裂研究。在这种情况下，负离子 ESI CID MS/MS 方法提供了来自交叉环裂解的诊断产物离子以及相同的主要 B_{1 个}离子（来自硫酸化 Gal _p），m/z 241，适用于所有异构体。同分异构二糖也经受增加的喷雾能量条件，诱导源内碎裂；然后将预先形成的 B ₁离子碎裂以产生与 [M-Na] ^-分析中发现的产物离子相似的产物离子。主要对m/z 138、139、151、153处的跨环碎片离子的相对丰度进行评估，可以清楚地区分二糖系列的成员。对于不同的比率M / Z 153分之151离子用的优势一致M / Z153 与裂解过程中涉及的键连接硫酸化碳的情况有关。还使用四极杆离子阱仪器（MS ⁿ分析）来比较使用三重四极杆仪器获得的结果。