Carbohydrate separation by hydrophilic interaction liquid chromatography on a 'click' maltose column

A general and efficient hydrophobic interaction liquid chromatography (HILIC) method has been developed for the separation of various kinds of carbohydrates, ranging from galactooligosaccharides, carrageenan oligosaccharides, sodium alginate, chitooligosaccharides to higher molecular weight fructooligosaccharides. Three types of oligosaccharides (acidic, basic, and neutral) were purified by semi-preparative HILIC. As a result, 18 oligosaccharides in high purity were obtained and their degrees of polymerization ranged from DP 2 to 7. Furthermore, oligosaccharides of plant origin were enriched and fractionated by solid-phase extraction (SPE) on a graphitized carbon cartridge. The oligosaccharide fractions that eluted from the cartridge were purified and then characterized by ESIMS and NMR spectroscopy. This strategy has led to the separation of a homogeneous raffinose family of oligosaccharides. Since the present method is universal, efficient and stable, separation and purification of various types of carbohydrates by HILIC seem to be possible.