Polysaccharide Characterization by Flow Field-Flow Fractionation-Multiangle Light Scattering: Initial Studies of Modified Starches

Chemically modified starches are commonly used for various purposes. Depending on the type of derivatization, a chemical degradation of the original polymeric structure may occur, resulting in a change of molar mass. It is therefore always of interest to know the molar mass and possibly the conformation of the derivative. Four commercially available hydroxypropyl and hydroxyethyl modified starches were examined by asymmetrical flow field-flow fractionation combined with multiangle laser light scattering. The weight-average molar mass and the molar mass distribution were determined, with emphasis put on the rapid analysis and studies of the suitable experimental conditions regarding flow rates so that accurate data were obtained. The molar mass distribution determinations showed good reproducibility and repeatability and were fast. Efforts to obtain conformational information are described.