Fraser B A, Tsui F P, Egan W
Carbohydr Res. 1979 Aug;73:59-65. doi: 10.1016/s0008-6215(00)85474-9.
Two isomeric-D-ribofuranosylribitols, derived from capsular polysaccharides of Haemophilus influenzae type b and Escherichia coli K 100, were methylated or acetylated, and the products analyzed by gas-liquid chromatography-mass spectrometry. The marked difference in the mass spectra of the methyl ethers of these disaccharides allowed clear distinction between 1- and 2-O-D-ribofuranosylribitol was characteristic for this disaccharide; its isomer, the (1 leads to 2)-linked species, has a base peak at m/e 57. The difference in the base peaks is attributable to fragmentation of the methylated ribitol, as both spectra display common ions characteristic of the methylated D-ribofuranosyl group. For the acetylated disaccharides, the mass spectra displayed common ions characteristic of the acetylated D-ribofuranosyl group. However, no ions similar to those found for the methylated ribitol allowed ready differentiation between the two acetates. Instead, their spectra displayed similar ions, differing somewhat in relative abundance; the M-1 ion, m/e 577, was obtained for both. Comparison of the relative abundance of m/e 139, 259, and 303 in the spectra of the two acetates did allow distinction between them.
从b型流感嗜血杆菌和大肠杆菌K100的荚膜多糖中获得的两种异构-D-呋喃核糖基核糖醇，进行甲基化或乙酰化处理，产物通过气相色谱-质谱联用仪进行分析。这些二糖甲基醚的质谱有显著差异，这使得能够清晰区分1-O-D-呋喃核糖基核糖醇和2-O-D-呋喃核糖基核糖醇；这种二糖的特征是其质谱中m/e 73处有一个基峰；其异构体，即(1→2)连接的物种，在m/e 57处有一个基峰。基峰的差异归因于甲基化核糖醇的碎片化，因为两种质谱都显示出甲基化D-呋喃核糖基的常见离子特征。对于乙酰化二糖，质谱显示出乙酰化D-呋喃核糖基的常见离子特征。然而，没有类似于甲基化核糖醇的离子能够轻易区分这两种乙酸酯。相反，它们的质谱显示出相似的离子，相对丰度略有不同；两者都得到了m/e 577的M-1离子。比较两种乙酸酯质谱中m/e 139、259和303的相对丰度确实可以区分它们。
