Field-flow fractionation Steric

By applying a steric sub technique (Giddings et al., 1980), field-flow fractionation was shown to have the potential to separate stable polysaccharide suprastructures in greater than hydrocolloidal diameters. Moon and Giddings (1993) used the procedure to size starch granules into a bimodal distribution of mass greater and less than 10 pm. [Pg.130]

Moon, M. H., and Giddings, J. C. (1993). Rapid separation and measurement of particle size distribution of starch granules by sedimentation/steric field-flow fractionation./. Food Sci. 58 1166-1171. [Pg.209]

High-Speed Separation of Large ( > 1 /btm) Particles by Steric Field-Flow Fractionation, T. Koch and J. C. Giddings, Anal. Chem., 58, 994 (1986). [Pg.300]

Separation of Human and Animal Cells by Steric Field-Flow Fractionation, K. D. Caldwell, Z.-Q. Cheng, P. Hradecky, and J. C. Giddings, Cell Biophys., 6, 233... [Pg.304]

Fig. 26. Schematic design of field flow fractionation (FFF) analysis. A sample is transported along the flow channels by a carrier stream after injection and focusing into the injector zone. Depending on the type and strength of the perpendicular field, a separation of molecules or particles takes place the field drives the sample components towards the so-called accumulation wall. Diffusive forces counteract this field resulting in discrete layers of analyte components while the parabolic flow profile in the flow channels elutes the various analyte components according to their mean distance from the accumulation wall. This is called normal mode . Particles larger than approximately 1 pm elute in inverse order hydrodynamic lift forces induce steric effects the larger particles cannot get sufficiently close to the accumulation wall and, therefore, elute quicker than smaller ones this is called steric mode . In asymmetrical-flow FFF, the accumulation wall is a mechanically supported frit or filter which lets the solvent pass the carrier stream separates asymmetrically into the eluting flow and the permeate flow which creates the (asymmetrical) flow field...

$Fig. 26. Schematic design of field flow fractionation (FFF) analysis. A sample is transported along the flow channels by a carrier stream after injection and focusing into the injector zone. Depending on the type and strength of the perpendicular field, a separation of molecules or particles takes place the field drives the sample components towards the so-called accumulation wall. Diffusive forces counteract this field resulting in discrete layers of analyte components while the parabolic flow profile in the flow channels elutes the various analyte components according to their mean distance from the accumulation wall. This is called normal mode . Particles larger than approximately 1 pm elute in inverse order hydrodynamic lift forces induce steric effects the larger particles cannot get sufficiently close to the accumulation wall and, therefore, elute quicker than smaller ones this is called steric mode . In asymmetrical-flow FFF, the accumulation wall is a mechanically supported frit or filter which lets the solvent pass the carrier stream separates asymmetrically into the eluting flow and the permeate flow which creates the (asymmetrical) flow field...$

Williams PS, Moon MH, Giddings JC (1992) Fast separation and characterization of micron size particles by sedimentation/steric field-flow fractionation role of lift forces. In Stanley-Wood NG, Lines RW (eds) Particle size analysis. Royal Society of Chemistry, Cambridge, pp 280-289... [Pg.183]

The techniques of field-flow fractionation appear to be well suited to colloid analysis. The special subtechnique of sedimentation FFF (SdFFF) is particularly effective in dealing with colloidal particles in the diameter range from 0.02 to 1 using the normal or Brownian mode of operation (up to 100 jU-m using the steric-hyperlayer mode). As a model sample for the observation of aggregate particles by SdFFF, of... [Pg.116]

Hoffstetter-Khun, S., T. Rosier, M. Ehrat, and H. M. Widmer, Characterization of yeast cultivations by steric field-flow fractionation, Anal. Biochem. 2 300-308 (1992). [Pg.1429]

Data Analysis. The computer program used for data analysis was developed at the Field-Flow Fractionation Research Center. The underlying theory is similar to that discussed by Giddings et al. (4). For normal mode characterizations, the fractograms are converted to particle size distributions by using developed theory. However, for steric mode analyses, calibration curves are required (15, 20). [Pg.313]

HETP Height equivalent to a theoretical plate Steric FFF Steric field flow fractionation... [Pg.767]

Caldwell, K.D. Cheng, Z.Q. Hradecky, P. Giddings, J.C. Separation of human and animal cells hy steric field-flow fractionation. Cell Biophys. 1984, 6, 233. [Pg.374]

Sanz, R. Cardot, R Battu, S. Galceran, M.T. Steric-hyperlayer sedimentation field flow fractionation and flow cytometry analysis applied to the study of Saccharomyces cerevisiae. Anal. Chem. 2002, 74 (17), 4496 504. [Pg.374]

Compton, B.J. Myers, M.N. Giddings, J.C. A single parti- 18. cle photometric detector for steric field-flow fractionation. [Pg.575]

Fig. 1 Principle of field-flow fractionation. 1—Solvent reservoir, 2-carrier liquid pump, 3—injection of the sample, 4— separation channel, 5—detector, 6—computer for data acquisition, 7—transversal effective field forces, 8—longitudinal flow of the carrier liquid. A—Section of the channel demonstrating the principle of polarization FFF with two distinct zones compressed differently at the accumulation wall and the parabolic flow velocity profile. B—Section of the channel demonstrating the principle of focusing FFF with two distinct zones focused at different positions and the parabolic flow velocity profile. C—Section of the channel demonstrating the principle of steric ITF with two zones eluting at different velocities according to the distance of their centers from the accumulation wall.

$Fig. 1 Principle of field-flow fractionation. 1—Solvent reservoir, 2-carrier liquid pump, 3—injection of the sample, 4— separation channel, 5—detector, 6—computer for data acquisition, 7—transversal effective field forces, 8—longitudinal flow of the carrier liquid. A—Section of the channel demonstrating the principle of polarization FFF with two distinct zones compressed differently at the accumulation wall and the parabolic flow velocity profile. B—Section of the channel demonstrating the principle of focusing FFF with two distinct zones focused at different positions and the parabolic flow velocity profile. C—Section of the channel demonstrating the principle of steric ITF with two zones eluting at different velocities according to the distance of their centers from the accumulation wall.$

Williams, P.S. Moon, M.H. Xu, Y. Giddings, J.C. Effect of viscosity on tetention time and hydrod3fnamic hft forces in sedimentation/steric field-flow fractionation. Chem. Eng. Sci. 1996, 51, 4477. [Pg.1713]

Koch, T. Giddings, J.C. High speed separation of large (> 1 /im) particles hy steric field-flow fractionation. Anal. Chem. 1986, 58, 994. [Pg.1717]

Field-flow fractionation is a family of high-resolution techniques capable of separating and characterizing colloids and macromolecules. In normal FFF, the particles form a Brownian-motion cloud that extends a short distance into the channel. Separation is possible because the solvent flows at different velocities at various points within the channel. The smaller particles, whose cloud protrudes out into the faster laminae, are transported more rapidly than the larger particles, so that the two populations are soon separated. In the steric mode of operation, which happens when the protrusion of particles into the flow stream is determined by their physical... [Pg.1900]

Fast Separation and Characterization of Micron Size Particles by Sedimentation/Steric Field-flow Fractionation Role of Lift Forces... [Pg.280]

Sedimentation Steric Field-flow Fractionation Roles of Lift Forces... [Pg.281]

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