Field-flow fractionation of macromolecules.

Field-flow fractionation (FFF) is a versatile family of techniques, applicable to macromolecules, colloids, and cell-sized particles. This paper focuses specifically on the applicability of FFF to macromolecules. Following a brief description of the principles of FFF, the characteristics of FFF that bear on its efficacy in separating macromolecules are summarized. The basis of selectivity is established. The general applicability of FFF to macromolecules is then surveyed. For this purpose macromolecular substances are divided into four classes, distinguished by a molecular weight cutoff of 10(6) and by aqueous versus organic solubility. The capabilities of different FFF subtechniques in fractionating these classes of macromolecules is then discussed.