Studies in field-flow fractionation

The studies presented in this dissertation introduce novel applications of field-flow fractionation (FFF). The Sedimentation field flow fractionation (SdFFF) subtechnique was used to study the adsorption of proteins on colloid particles and, operating in the steric mode, the behavior of rod-shaped particles, chromosomes and Escherichia coli (E. coli) mutants of varying motility. Because the inertial lift force greatly influences retention in steric/hyperlayer FFF, it was the subject of extensive experimentation.; The adsorption of human IgG on the surface of polystyrene (PS) latex beads was studied. The adsorption showed a Langmuir type isotherm although it was found to be an irreversible process. From the study, we concluded that the lateral interaction between adsorbed protein molecules plays an important role in the adsorption of IgG on the surface of PS latex beads.; It was found that the inertial lift force became dominant at high flow velocity and played an important role in the particle retention and selectivity. Under the influence of the inertial lift force, the selectivity was found to be affected by both flow velocity and field strength. The optimization of Sd/StFFF separation is discussed.; Fractionation, retention, and selectivity features of rod-shaped particles were determined and compared to those of spheres. The rod-shaped particles of the same diameter were separated according to length. The influences of the rotational motion of these rod-shaped particles and the hydrodynamic lift forces on particle retention are discussed.; Extensive experimentation was directed toward the selection of an appropriate carrier solution and channel surface. The separation of human RBC in Sd/StFFF at high flow velocity was investigated. The lift forces was found to play a critical role in the cell separation. The behaviors of Escherichia coli (E. coli) in sedimentation and flow FFF were studied. Cells of different motility may be separated by both SdFFF and FlFFF. The diffusion coefficients of different types of E. coli were determined by FlFFF.