*3.3. Chemical Analysis*

Fucose content was determined using cysteine hydrochloride–sulfuric acid method with L-fucose as the standard [27]. Sulfate content was analyzed using ion chromatography with potassium sulfate as the standard. Total sugar content was measured by phenol-sulfuric acid method. Uronic acid was tested using modified carbazole method with D-glucuronic acid as the standard [28]. Monosaccharide composition was estimated with high-performance liquid chromatography (HPLC) according to the method of Zhang et al. [29]. The proportion of monosaccharide was evaluated by calculating the molar ratio of other monosaccharide to fucose. Infrared spectra were recorded with a Nicolet-750 FT-IR spectrometer. Average molecular weight was determined by high performance gel filtration chromatography (HPGPC) on TSK G4000 PWxl or G3000 PWxl column eluted with 0.7% Na2SO4 using a series of dextrans with different molecule weight as standard.
