2.5. Determination of homogeneity of polysaccharides and their molecular weight (Mw)
The determination of the homogeneity and molar mass (Mw) of the fractions were performed on a Waters high-performance size-exclusion chromatography (HPSEC) apparatus coupled to a differential refractometer (RI) and
a Wyatt Technology Dawn-FMulti-Angle Laser Light Scattering (MALLS) detector. The eluent was 0.1 M NaNO3, containing 0.5 g L−1 NaN3. The polysaccharides solutions were filtered through a membrane with 0.22 m diameter pores (Millipore). The specific refractive index increment (dn/dc) was determined using a Waters 2410 detector, the samples being dissolved in the eluent, five increasing concentrations, ranging from 0.2 to 1.0 mg mL−1 being used to determine the slope of the increment.