Advances in online viscometry: extending the limits of detection for intrinsic viscosity and hydrodynamic radius

Stepan Podzimek

Presented by: Stepan Podzimek, Ph.D., Department Head Analytical and Physical Chemistry, SYNPO, and Steven Trainoff, Ph.D., Chief Scientist, Wyatt Technology Corporation
Presented Live: October 19, 2016

Online differential viscometers are commonly coupled to gel permeation chromatography (GPC) for molar mass determination via the Mark-Houwink-Sakurada relation, or alternatively the universal calibration technique. However, viscometry’s real strength is realized when coupled with multi-angle light scattering (MALS) to characterize size, shape, branching, and aggregation of polymers and biomolecules, providing deeper insight into macromolecular properties.

New developments in the technology of differential viscometers extend their capabilities to the realm of compact molecules such as proteins. Improved sensor technology in conjunction with a patented thermal balancing system allows for dramatically improved sensitivity and near immunity to pump pulses. We describe a new differential viscometer, incorporating these advances and others, that measures hydrodynamic radius with sensitivity exceeding that of online dynamic light scattering, especially for globular proteins and other compact macromolecules.