Field-flow fractionation for molecular-interaction studies of labile and complex systems: A critical review.

Asymmetrical flow field-flow fractionation (AF4) has attracted considerable attention as a size-based separation technique, due to its mild separation conditions, broad working range (from approximately 10 to 10 Da molecular mass or from 1 nm to 1 μm particle diameter), and versatility. AF4 is primarily being used to measure particle size, polydispersity, and physical stability of various systems, such as (bio)-macromolecules and nanoparticles. In comparison with size-exclusion chromatography (packed column), AF4 (open channel) allows separation while preserving labile structures.