COIL DIMENSIONS AND CONFORMATION OF MACROMOLECULES IN AQUEOUS MEDIA FROM FLOW FIELD-FLOW FRACTIONATION/MULTI-ANGLE LASER LIGHT SCATTERING ILLUSTRATED BY STUDIES ON PULLULAN

摘要

For a comprehensive description of the steric structure of macromolecules, which includes molecular shape as well as coil density and flexibility, a novel analytical technique for aqueous systems is introduced. The reliability of the method is illustrated by investigations on narrowly distributed pullulan standards in the molar mass range from 10(5) to 10(6) gmol(-1). Hydrodynamic information (D, R(D)) was yielded by flow field-flow fractionation, while simultaneous scattering experiments delivered the corresponding 'static' dimension R(G) and molar mass M. The observed asymmetry-factor was R(G)/R(D)=1.7 With increasing molar mass the mean coil density rho(Pol) decreased from 19.1 to 2.6 mg ml(-1) and the calculated persistence lengths l(p) increased, ranging from 1.4 to 3.1 nm. The results were found to be in good agreement with literature data and confirm the analytical potential of the applied technique. (C) 1997 Elsevier Science Ltd. [References: 43]