Solving SEC/GPC Limitations with Multi-Angle Light Scattering and Asymmetric-Flow Field-Flow Fractionation

Stepan Podzimek

Presented by: Stepan Podzimek, Ph.D., Wyatt Technology
Presented Live: April 19, 2022

Size-exclusion chromatography (SEC), also known as gel-permeation chromatography (GPC), has become the dominant technique for the determination of molar mass distributions of synthetic and natural polymers. The method is relatively simple and easy to use. However, limitations of this technique may lead to results that are not only incorrect, but even completely misleading.

The principal limitations of SEC are: 1) lack of appropriate column calibration standards; 2) non-ideal separation due to column interactions beyond purely steric; and 3) shear degradation of HMW fractions. These limitations can revealed—and often solved—by incorporating a multi-angle light scattering (MALS) detector following the SEC separation. Shear degradation and most of the non-steric effects can be eliminated by applying an alternative separation technique, asymmetric-flow field-flow fractionation (AF4).

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