Field flow fractionation techniques

Cdlfen, H. and Antonietti, M.t Field-Flow Fractionation Techniques for Polymer and Colloid Analysis. VoL 150, pp. 67-187. 

Figure 1. Schematic of an FFF channel with the separation mechanism for normal FFF shown in detail. Reprinted from [7] Beckett, R. and Hart, B. T. Use of field flow fractionation techniques to characterize aquatic particles, colloids and macromolecules . In Environmental Particles. Vol. 2, IUPAC Series on Analytical and Physical Chemistry of Environmental Systems. Series eds. Buffle, J. and van Leeuwen, H. P., pp. 165-205. Copyright 1993 IUPAC. Reproduced with permission...

Most data about the Ludwig-Soret effect of polymers in solution have been obtained from thermal field-flow fractionation (TFFF), developed by Giddings and coworkers [17,18]. TFFF is one member of the family of field-flow fractionation techniques, which are all characterized by a laminar flow of the polymer solution or colloidal suspension within a relatively narrow channel. An external field, which may be gravitation, cross-flow, or temperature as in TFFF, is applied... 

While polydisperse model systems can nicely be resolved, the reconstruction of a broad and skewed molar mass distribution is only possible within certain limits. At this point, experimental techniques in which only a nonexponential time signal or some other integral quantity is measured and the underlying distribution is obtained from e.g. an inverse Laplace transform are inferior to fractionating techniques, like size exclusion chromatography or the field-flow fractionation techniques. The latter suffer, however, from other problems, like calibration or column-solute interaction. 

The coverage of separation techniques in many important textbooks in chemical analysis is largely limited to chromatography (e.g., refs. 9, 12, 13). While chromatography is of central importance in analysis, the omission of modern electrophoretic (both gel and capillary) and field-flow fractionation techniques leaves a large void in the description of separative capabilities, particularly in the biochemical and macromolecular realm. 

Field-Flow Fractionation Techniques for Polymer and Colloid Analysis... 

---