Field-flow fractionation techniques for polymer and colloid analysis

Abstract

Field-flow fractionation (FFF) is a family of flexible analytical fractionating techniques which have the great advantage that separation is achieved solely through the interaction of the sample with an external physical field and without a stationary phase. This has the advantage of avoiding the large variety of problems due to non-specific sample interactions with column materials associated with other chromatographic techniques. Furthermore, the range of information accessible is very broad and often complimentary when various FFF techniques are applied, so that even very complex systems with broad size distribution, heterogeneous mixtures or strongly interacting systems can be characterized. The range of particle sizes or hydrodynamic radii which can be separated is very broad ranging from 1 nm to 100 μm, covering the entire colloidal, polymeric and even most of the microparticle domain. No other fractionating technique can cover about 5 orders of magnitude of the particle size, even with complex distributions. This review will introduce the basic principles, theory, and experimental arrangements of the various FFF techniques focusing on the most relevant for praxis: Sedimentation-FFF (S-FFF), Thermal-FFF (Th-FFF) and Flow-FFF (Fl-FFF). In a second part, selected applications of these techniques both to synthetic and biological samples will illustrate applications under a variety of conditions, where problems and potential pitfalls as well as recent developments are also considered. Due to the wide spread of available information, an organized guide to the primary literature is given which contains the results from about 70% of the total literature published on FFF in listed journals so far. © Springer-Verlag Berlin Heidelberg 2000.