*4.2. Analytical Methods*

The total sugar content of samples were determined according to the method of Dubois et al. using L-fucose as the standard [27]. The sulfate content was analyzed by ion chromatography using K2SO4 as the standard. Uronic acid was estimated via a modified carbazole method using d-glucuronic

acid as the standard [28]. The neutral sugar composition was determined by PMP-HPLC precolumn derivatization chromatography using ribose as interior label [29]. The molecular weight was assayed by an HP-GPC chromatography using a series of dextrans with different molecular weights as standards. A series of dextrans were purchased from the National Institute for the Control of Pharmaceutical and Biologic Products (China). Other standard reagents were purchased from Sigma-Aldrich (Milwaukee, WI, USA).
