Assessment of alginic acid molecular weight and chemical composition through capillary electrophoresis.

The polydispersity of alginic acids regarding distributions in molecular weight and chemical composition is analyzed by capillary electrophoresis. Low concentrations of linear polyacrylamide in the electrolyte provide the means for separation of alginate fractions into the megadalton range, while high-resolution polysaccharide mapping of structural variants could be achieved at higher LPAA concentrations. The fraction and block length of the structurally important guluronic acid constituent is determined through the selective complexation with calcium ions. The methodology presented here might serve as a general approach for the assessment of alginate composition and size and the relation to technical properties desired in medical and pharmaceutical applications.