Field-flow fractionation characterization

Benedetti, M., Ranville, J.F., Ponthieu, M. and Pinheiro, J.P. (2002) Field-flow fractionation characterization and binding properties of particulate and colloidal organic matter from the Rio Amazon and Rio Negro, Organic Chemisrty 33, 269-279. 

Biomolecule Separations. Advances in chemical separation techniques such as capillary zone electrophoresis (cze) and sedimentation field flow fractionation (sfff) allow for the isolation of nanogram quantities of amino acids and proteins, as weU as the characterization of large biomolecules (63—68) (see Biopolymers, analytical techniques). The two aforementioned techniques, as weU as chromatography and centrifugation, ate all based upon the differential migration of materials. Trends in the area of separations are toward the manipulation of smaller sample volumes, more rapid purification and analysis of materials, higher resolution of complex mixtures, milder conditions, and higher recovery (69). 

Venema, E., deLeeuw, P., Rraak, J.C., Poppe, H., Tijssen, R. (1997). Polymer characterization using online coupling of thermal field flow fractionation and hydrodynamic chromatography. J. Chromatogr. A 765(2), 135-144. 

In conclusion one can say that SEC is a very powerful method for polymer characterization, especially in combination with other composition sensitive or absolute calibration methods. A big advantage is also that the sample amount is fairly small, typically 10 mg. For more complex polymers, such as polyelectrolytes, enthalpic effects often become dominant and also for rather high molecular weight polymers chromatographic methods such as field-flow fraction (FFF) techniques might be more suitable. For fast routine measurements linear columns are often used. 

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...

Field-flow fractionation, commonly designated as FFF, is a versatile family of separation techniques able to separate and characterize an enormous assortment of colloidal-supramolecular species in a wide range of dimensions/molecular weights. Giddings is considered the inventor of this technique since he contributed to the development of theory, different techniques, instrumentation, methodology, and applications [1], even if studies on the theoretical fundamentals of fractionation under force and flow fields had appeared before and/or independently [2]. 

One such consequence is their use in the physical characterization of colloidal dispersions and macromolecular solutions. Let us highlight one such application through one element of a class of analytical separation techniques known as field flow fractionation (FFF). 

C. M. Frietch, and C. A. Kelly. Characterization of Submicron Aqueous Iron(lll) Colloids by Sedimentation Field Flow Fractionation, Anal Chem. 2001, 73.4815.)... 

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... 

In principle, all powerful element-specific methods that are able to monitor continuously the effluents of separation processes commonly in the range of a few mimin-1 and in element concentrations of some Klpg liter-1. A well-suited method is based on modern element-specific quadrupole mass spectrometry (MS) with an inductively coupled plasma (ICP) interface to the separation unit [e.g., liquid chromatography (LC) or field-flow fractionation (FFF)].Tlie ICP-MS detection can also be used for continuously characterizing the effluent of any kind of packed column (Metreveli and Frimmel, 2007). By this, the transport and elution properties of... 

Bolea, E., Bouby, M., Laborda, F., Castillo, J. R., and Geckeis, H. (2006). Multielement characterization of metal-humic substances complexation by size exclusion chromatography, asymmetrical flow field-flow fractionation, ultrafiltration and inductively coupled plasma-mass spectrometry detection A comparative approach. J. Chromatogr. A 1129, 236-246. 

Another technique widely used for size separation of humic materials is field-flow fractionation (FFF) (e.g., Baalousha et al., 2006 Boehme and Wells, 2006 Geckeis et al., 2003 Hassil ov et al., 2007 Siripinyanond et al., 2005 Suteerapataranon et al., 2006 Zanardi-Lamardo et al., 2002). This technique was developed and introduced in 1966 by Giddings (1966) as a method for the separation and characterization of materials ranging in size from macromolecules to particulates. Similar to SEC, FFF... 

Contado, C., Bio, G., Fagioli, F., Dondi, F., and Beckett, R. (1997). Characterization of River Po particles by sedimentation field-flow fractionation coupled to GFAAS and ICP-MS. Colloids Surf. A 120,47-59. 

Manh Thang, N., Geckeis, H., Kim, J. I., and Beck, H. P. (2001). Application of the flow field flow fractionation (FFFF) to the characterization of aquatic humic colloids Evaluation and optimization of the method. Colloids Surf. A 181(1-3), 289-301. 

Schimpf, M. E., and Petteys, M. P (1997). Characterization of humic materials by flow field-flow fractionation. Colloids Surf. A 120, 87-100. 

Siripinyanond, A., Barnes, R. M., and Amarasiriwardena, D. (2002). Flow field-flow fractionation-inductively coupled plasma mass spectrometry for sediment bound trace metal characterization. J. Anal. At. Spectrom. 17(9), 1055-1064. 

This paper outlines the basic principles and theory of sedimentation field-flow fractionation (FFF) and shows how the method is used for various particle size measurements. For context, we compare sedimentation FFF with other fractionation methods using four criteria to judge effective particle characterization. The application of sedimentation FFF to monodisperse particle samples is then described, followed by a discussion of polydisperse populations and techniques for obtaining particle size distribution curves and particle densities. We then report on preliminary work with complex colloids which have particles of different chemical composition and density. It is shown, with the help of an example, that sedimentation FFF is sufficiently versatile to unscramble complex colloids, which should eventually provide not only particle size distributions, but simultaneous particle density distributions. 

Field-Flow Fractionation A Versatile Method for the Characterization of Mac-romolecular and Particulate Materials, J. C. Giddings, Anal. Chem., 53, 1170A (1981). 

Colloid Characterization by Sedimentation Field-Flow Fractionation. I. Monodis-perse Populations, J. C. Giddings, G. Karaiskakis, K. D. Caldwell, and M. N. Myers, J. Colloid Interface Sci., 92, 66 (1983). 

Separation and Size Characterization of Colloidal Particles in River Water by Sedimentation Field-Flow Fractionation, R. Beckett, G. Nicholson, B. T. Hart, M. Hansen, and J. C. Giddings, Wat. Res., 22, 1535 (1988). 

High-Speed Size Characterization of Chromatographic Silica by Flow/Hyperlayer Field-Flow Fractionation, S. K. Ratanathanawongs and J. C. Giddings, J. Chromatogr., 467, 341 (1989). 

Gunderson JJ, Giddings JC (1989) Field-flow fractionation. In Booth C, Price C (eds) Polymer characterization. Pergamon, Oxford, pp 279-291... 

Giddings JC, Caldwell KD, Jones HK (1987) Measuring particle size distribution of simple and complex colloids by sedimentation field-flow fractionation. In Provder T (ed) Particle size distribution assessment and characterization. American Chemical Society, Washington, DC,pp 215-230... 

Giddings JC, Kumar V, Williams PS, Myers MN (1990) Polymer separation by thermal field-flow fractionation high speed power programming. In Craver CD, Provder T (eds) Polymer characterization physical properties, spectroscopic, and chromatographic methods. American Chemical Society, Washington, DC, pp 1-21... 

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