固相酸解法制备古糖酯寡糖及其电喷雾质谱分析

Preparation of Oligoguluronate Sulfates by Solid Phase Acid Degradation and Analysis by Negative-ion Electrospray Tandem Mass Spectrometry

以褐藻酸中分离的聚古罗糖醛酸（PG）为原料，以三氧化硫-吡啶为硫酸酯化试剂，采用正交实验法确定了制备高硫酸酯基取代古糖酯（PGS）的最佳工艺条件，并采用2D-NMR分析对其结构进行了确证。本文建立了一种新的环境友好型固相酸解方法以制备PGS的寡糖（即采用732^#阳离子交换树脂这种固态酸对PGS进行降解）。结果表明，当732。阳离子交换树脂用量为200mg／mL、PGS的质量分数为2％时，在100℃下降解6h可得到重均分子质量（Mw）小于3000的PGS寡糖，经Bio-GelP6凝胶层析柱分离可以得到13个聚合度单一的寡糖组分F1-F13。电喷雾质谱（ESI-MS）分析结果表明，F1-F13分别是聚合度为1-13的PGS寡糖。

Polyguluronate sulfate（PGS） with a high degree of sulfate substitution was prepared by chemical sulfation with sulfur trioxide pyridine complex（ SO3-Py） on the basis of polyguluronic acid（PG） , which was isolated from the hydrolysate of alginate. The optimum sulfation conditions were determined by orthogonal design method and the structure of PGS was confirmed by 2D-NMR spectroscopy. A new environment-friendly degradation method （the so called solid phase acid degradation） was developed to prepare PGS oligosaeeharides, in which 732^# resin was used as an acidic degradation medium. The results of degradation show that the weight average relative molecular weight（Mw） of PGS oligosaccharides was lower than 3000, when the ratio of 732^# resin is 200 mg/mL and mass fraction of PGS is 2%, degradation temperature is 100 ℃ and degradation time is 6 h. Thirteen PGS oligosaccharides （F1-F13） were obtained by Bio-Gel P6 column separation. The polymerization degree of F1-F13 is from one to thirteen, respectively, demonstrated by ESI-MS analysis. The solid phase acid degradation method was used to solve the problems of environmental pollution, inorganic salts separation and corrosion of reactors, which are universal in traditional acid degradation methods, and it provides a new approach to preparation of oligosaccharides.