丹皮多糖2b主要成分的相对分子质量的测定

Determination of relative molecular weight in polysaccharide-2b of moutan(PSM_(2b))

目的测定丹皮多糖2b(PSM2b)主要成分的相对分子质量,为建立对照品的标准提供依据。方法PSM2b经Sepharose 4B柱分离,冷冻干燥后得到丹皮多糖的两个成分PSM2b-A和PSM2b-B,采用HPLC法检测均一性和相对分子质量;并分别以0.7%N a2SO4溶液和超纯水作为流动相进行比较。结果PSM2b-A为均一性的糖蛋白,是PSM2b的主要成分。流动相为0.7%N a2SO4溶液时,其相对分子质量为3.596 2×105,分散度指数(D)为4.15。流动相为超纯水时,其相对分子质量为4.758 5×105,分散度指数为1.03。结论采用HPLC法测定丹皮多糖主要成分的相对分子质量时,不同流动相测定的结果有差异,流动相采用超纯水比0.7%N a2SO4溶液更为适合。

Objective To determine the relative molecular weight （Mr） of polysaccnaride-2b of moutan （PSM2b） to establish the standard of reference substance. Methods PSM2b, was separated by a Sepharose 4B column and then PSM2b-A and PSM2b-B were obtained after cryodesiccation. Then HPLC was used to determine their Mr. Ultrapure water was used as mobile phase to compare with 0.7% Na2SO4 solution. Results PSM2b-A was pure. The Mr and polydispersity （D） of PSM2b-A obtained by use of dextran as standard were 3. 596 2 × 10^5 and 4.15 in 0.7% Na2SO4 solution phase, respectively, and in ultrapure water phase the Mr and D were 4. 758 5 × 10^5 and 1.03, respectively. Conclusion Different results are detected by different mobile phases in determination of Mr and D of PSM2b-A by HPLC. And the ultrapure water as mobile phase is more suitable than 0.7% Na2SO4 solution.