Size exclusion chromatography (SEC) is frequently applied in industries and many labs for Mw and Mw distribution (MwD) determination because of its time and cost efficiency. Since the retention volume of SEC depends on the hydrodynamic volume rather than Mw, the use of globular coil-type standards Pulluan(P)-82, leads to a significant overestimation of Mw of many plant and fungal polysaccharides with flexible chain conformation. In this research, we developed a Mw standards with linear structure and expanded chain conformation. The standard kits were characterized and compared with the performance of P-82.
Lentinus edodes (PLE ), Guar galactomannan (GG ), CM-cellulose (CMC )
Shodex P-82, PS-OBG-Mw (From Putus Macromolecular company)
GPC and laser LLS
Table 1：the Mw of the samples by GPC and LLS
Samples Mw1 Mw2 Mw3
PLE 707k 1160k 790k
GG 122k 331k 112k
CMC 130k 354k 148k
Mw1: determined by PS-OBG-GMw
Mw2: determined by Pullulan-82
Mw3: determined by LLS
The three polysaccharides in Table 1 were widely accepted to adopt expanded chain conformation in solution. The Mw determined by using Putus standard was demonstrated to be more accurate than by using Pullulan-82, compared to their real Mw measured by LLS. Using P-82 to determine Mw of expanded chain leads to a significant overestimation.
Edited by putus, 20 July 2009 - 11:04 PM.