A Study On The Sulfatinal Modification Of Dextran And Purification

Polysaccharide is distributed in nature extensively, play an importance role in activity of life. The modification of saccharide could strengthen its function and enlarge its application range. Through modification, the saccharide can be developed as functional food and special medicine of saccharide. The study of modifying saccharide has become an important research field.In this paper, we regard medical dextran as the research object, sulfated dextran, a kind of water soluble sulfated derivative, was obtained from sulfatinal modification of dextran with chlorosulfonic acid-pyridine. The degree of sulfated was used as the guideline and chlorosulfonic acid/ pyridine ratio, reaction time, reaction temperature were used as restricted factors. The optimal reaction conditions were conformed by the orthogonal experiments. The optimization of the sulfation-techniques is volume ratio of chlorosulfonic acid and pyridine: 1:5; reaction time: 2 hours; reaction temperature: 80℃. Analyzed by the high performance liquid chromatography, the moleculeweight(MW) of sulfated dextran(SD) is more than that of dextran before modification. After ultraflltrated, the MW of the SD parts with MW more than 10kD has little changed, in the parts with MW less than 10kD, the MW of SD is less than that of parts of dextran, and the distribution range of SD MW is smaller than that of dextran. It showed the ultrafitration is one effective method of separation. The UV and IR spectrum of SD showed that characteristic absorptions of sulfated eater bond at wavelength of 260nm and 1260 cm-1, 800-810 cm-1 respectively, those results suggested that the modified object has the -SO3 group, the polysaccharide's conformation and some physicochemical properties were changed by sulfated radical.