Differential viscometers are commonly used with size-exclusion chromatography (SEC) to determine the intrinsic viscosity (IV or η) of polymers, from which molar mass can be derived under certain assumptions. However, the real strength of differential viscometry is realized when combined with size-exclusion chromatography and online multi-angle light scattering (SEC-MALS-IV) to measure, from first principles, both molar mass and hydrodynamic (viscometric) radius. SEC-MALS-IV systems fully characterize macromolecules in terms of size, conformation, branching, and aggregation.

Novel low-volume, differential viscometry sensor technology provides dramatically improved sensitivity and near immunity to pump pulses, as well as extremely low dispersion. Instruments based on this technology are particularly appropriate for applications using ultrahigh-performance liquid chromatography (UHPLC) and advanced polymer chromatography (APC) when combined with low-volume MALS, UV, and differential refractive index detectors.

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