Corn Starch (2) (DMSO/DMF Eluent)

For the analysis of polysaccharides such as starch, which does not dissolve easily in water, samples used to be dissolved in DMSO before doing the analysis by GFC mode with an aqueous an eluent. However, this method was unsatisfactory as undissolved components were left undetected. In contrast with the above, if a mixed eluent of DMSO/DMF containing LiBr is used as an eluent, the solubility of starch in the eluent is increased allowing a more accurate GFC analysis. There are some cases in which starch has ionic functional groups such as carboxyl groups. An addition of LiBr to the eluent allows GFC analysis without interference from the ionic groups. The sample used in this analysis example was prepared by adding DMSO to starch and then heating the mixture to 120 deg.C to dissolve the starch using OHpak SB-806 HQ (a column for GFC separation).
Please refer to Corn Starch (1) (Aqueous Eluent).


Sample : Starch
Corn starch in DMSO

Column       : Shodex OHpak SB-806 HQ (8.0mmID*300mm)
Eluent       : DMSO/DMF=75/25
               5mM LiBr in DMSO/DMF=75/25
Flow rate    : 0.25mL/min
Detector     : Shodex RI
Column temp. : 40deg-C