METHODICAL ASPECTS OF CHARACTERIZATION OF ALGINATE AND PECTATE BY LIGHT-SCATTERING AND VISCOMETRY COUPLED WITH GPC

The reliability of light scattering depends on the complete removal of extraneous matter from the polymer solution. The use of membrane filters to clarify aqueous solutions is common practice. This paper studies the effect of the pore size of the membrane filter on the light scattering of several polyuronides. Alginate and pectates were fractionated by GPC on Sepharose gels, and the eluent was taken after filtration for light scattering and viscosity measurements. Light scattering data were represented as GUINIER plots to provide information about the scattering functions and scattering level. While for alginate satisfactory separation of molecularly dispersed polymer from extraneous material was achievable, heterogeneity of pectates did not allow an unequivocal differentiation of extraneous matter from 'proper' pectate. Dextran sulphate was included as a model substance which was free of extraneous material.