Determination of Fucoidan Molecular Weights

The molecular weights (MW) of fucoidan fractions were determined by High Performance Size Exclusion Chromatography (HP-SEC) using an Ultimate iso-3100SD pump with WPS-3000 sampler (Dionex, Sunnyvale, CA, USA) connected to an RI-101 refractive index detector (Shodex, Showa Denko K.K., Tokyo, Japan). The samples were dissolved in 1 ml HP-SEC buffer (100 mM sodium acetate, pH 6) and filtered through 0.22 μm filters. 100 µL of fucoidan samples (3 mg/mL) were injected into a Shodex SB-806 HQ GPC column (300 × 8 mm) coupled with a Shodex SB-G guard column (50 mm × 6 mm) (Showa Denko K.K., Tokyo, Japan) [56 (link)]. Elution was carried out at a flow rate of 0.5 mL/min at 40 °C [56 (link)]. Pullulan samples of molecular weight 1, 5, 12, 110, 400, and 800 kDa were used as standards [56 (link)].