Table 1e.

Separation and purification of by AEC and GFC.

	Anion exchange chromatography（AEC)	Gel filtration chromatography（GFC)
Principle	Polysaccharides are separated according to charge and polarity indices	Fractional distillation according to polysaccharide size and shape
Elution order	① Acidic polysaccharides with high uronic acid content could strongly bind to anion resin, while neutral polysaccharides had no interaction with anion resin, so they were eluted first. ② Fractionation is performed by using a combination of gradient elution practices and different ionic eluents	① Macromolecules and high molecular weight polysaccharides do not enter the pores of the gel and are first eluted; ② Polysaccharides with small and low molecular weights block the pores of the gel and are finally eluted.
Chromatographic column	Diethylaminoethyl（DEAE)	Agarose, agar propylene, Superdex, biogel and agarose
Anion exchanger/Gel selection	Depends on small-scale experiments and the concentration of uronic acid in the polysaccharide	Much depends on the nature and source of the polysaccharide to be fractionated
limitation	Long time consuming; According to different uses, different resins need to be selected, and the general scope of application is small.	Instruments are expensive, inefficient, lack automation and difficult to scale up.