Molecular weight determination of lignosulfonates by size-exclusion chromatography and multi-angle laser light scattering.
A lignosulfonate sample was fractionated according to the solubility in ethanol-water. The fractions were analysed by aqueous size exclusion chromatography (SEC) combined with in-line multi-angle laser light scattering (MALLS), and by static MALLS. Satisfactory SEC results were obtained with aqueous phosphate buffer containing DMSO and SDS. The refractive index increment (dn/dc) varied from 0.186 to 0.205 ml/g, depending on Mw and the degree of sulfonation. The second viral coefficient (A2) was 7 x 10(-3) ml mol/g2. The weight-average molecular weight (Mw) of the fractions varied from 4600 up to 398 000 g/mol. and the polydispersity (Mw/Mn) varied between 1.3 and 3.5.
Fredheim
Guro Elise
GE
Ostfold College, Sarpsborg, Norway.
Braaten
Svein Magne
SM
Christensen
Bjørn E
BE
D002850:Chromatography, Gel / Q000379:methods*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D007834:Lasers; D008970:Molecular Weight; D012031:Refractometry; D012542:Scattering, Radiation; D013451:Sulfonic Acids / Q000737:chemistry*
D013451:Sulfonic Acids