MW of fucoidan polysaccharide is around 20 kDa. The fractination range of Sephadex G-50 is 1.5-30 kDa, so it is just appropriate for fucoidan separation. You can use also G-75 (MW range 3-80 kDa).

Stokes radii of 20kDa protein and 20kDa polysaccharide are very different. Characteristics of Sephadex specified for globular proteins.

Moreover this polysaccharide has complex molecular weight distribution.

G50 is not suitable. G75 is also not optimal choice.

I recommend use Sephadex G100-150-200 or Sepharose-4-FF.

Hi

thanks every body for your answers.