Field-Flow Fractionation

Abstract Field-flow fractionation (FFF) is a separation method first described in 1966 (I). FFF is an elution technique, like chromatography, and the experimental sequence of pump, column, detector, and fraction collector is much like that used in chromatographic operations (2-4). However, FFF appears to be unique in its ability to separate an extremely broad range of molecules, macromolecules, supramacromolecular structures, colloidal particles, and larger particles at a high level of resolution. In dealing with these complex and often refractory materials, FFF has a number of unique advantages (5). Along with its intrinsically high resolving power, FFF is a versatile technique in which experimental conditions can be varied widely to optimize the range, speed, and power of the separation. FFF is also unusual in that the characteristics of the separation can be calculated rather exactly in terms of well-defined physicochemical parameters such as molecular weight, size, charge, etc. The equations used for this purpose can be inverted to yield molecular weight and other important parameters for the components of complex mixtures (3-6).