Interference prevention in size-exclusion chromatographic analysis of debranched starch glucans by aqueous system
Journal
Journal of Agricultural and Food Chemistry
Journal Volume
59
Journal Issue
11
Pages
5890-5898
Date Issued
2011
Author(s)
Abstract
Branch chain-length distribution of amylopectin plays an important role on the characteristics of starch. One of the adapted protocols for determining the chain-length distribution and mass proportion of starch molecules is that starch is debranched with isoamylase and then analyzed by using high-performance size-exclusion chromatography coupled with multiangle laser-light scattering and refractive index detection (HPSEC-MALS-RI). However, ammonium sulfate in commercial isoamylase and acetate in debranching buffer give significant interferences on the chromatograms because of their undesirable ionic interactions with column sorbent materials. This study deals with development for correcting those interferences. A weak anion-exchange resin or selective precipitation with barium acetate was employed to remove sulfate prior to HPSEC determination. The interference of acetate was overcome by means of high ionic strength eluent, 0.3 M sodium nitrate. The specific refractive index increment (dn/dc) of amylodextrin was determined to be 0.147 using the modified conditions and was applied to calculate the molecular weight distribution of debranched starch molecules. ? 2011 American Chemical Society.
Subjects
ammonium sulfate
amylopectin
amylose
chain-length distribution
ionic interaction
refractive index increment dn/dc
size-exclusion chromatography
starch
Type
journal article