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

ABSTRACT

Objective To determine the relative molecular weight(M_r) of polysaccharide-2b of moutan(PSM_(2b)) to establish the standard of reference substance.Methods PSM_(2b) was separated by a Sepharose 4B column and then PSM_(2b-A) and PSM_(2b-B) were obtained after cryodesiccation.Then HPLC was used to determine their M_r.Ultrapure water was used as mobile phase to compare with 0.7% Na_2SO_4 solution.Results PSM_(2b-A) was pure.The M_r and polydispersity(D) of PSM_(2b-A) obtained by use of dextran as standard were 3.596 2?10~(5) and 4.15 in 0.7% Na_2SO_4 solution phase,respectively,and in ultrapure water phase the M_r and D were 4.758 5?10~(5) and 1.03,respectively.Conclusion Different results are detected by different mobile phases in determination of M_r and D of PSM_(2b-A) by HPLC.And the ultrapure water as mobile phase is more suitable than 0.7% Na_2SO_4 solution.