Field-flow Fractionation of Polymers: One-phase Chromatography

Field-flow fractionation (FFF) is introduced as a one-phase chromatographic system utilizing an external field to differentially retain high molecular weight polymeric and particulate species. The principles and theory of FFF are described. FFF and exclusion chromatography are then compared on the basis of their underlying separative mechanisms, and the way that these mechanisms influence and limit experimental capabilities. This comparison is continued in a more quantitative way by examining fundamental column selectivity requirement for polymer fractionation. Several examples of polymer fractionation by FFF are then shown. Finally, some of the extreme limits of FFF performance are discussed, including resolution, separation speed and high and low molecular weight limits.