Potential of size-exclusion chromatography and asymmetric flow field-flow fractionation in separation and characterization of plant polysaccharides

Size-exclusion chromatography (SEC) and asymmetric flow field-flow fractionation (AF4) are elution-based techniques for separation and characterization of (bio)macromolecules including plant polysaccharides. These two techniques separate the macromolecules according to their hydrodynamic volume in solution. The primary reason for the separation of polysaccharides with a dispersed nature is the need for accurate information on the molar mass distribution (MMD), which cannot be obtained without the separation of macromolecular species into narrowly distributed fractions. Depending on the detectors coupled to the separation, other information such as size, branching, and conformation can also be obtained across the separated fractions. This review summarizes the SEC and AF4 methodology used for separation and characterization of plant polysaccharides with industrial and/or nutritional importance. The key differences between the two techniques are highlighted and recommendations are given for method selection.