• Korean Membrane Journal
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• v.3 no.1
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• pp.59-68
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• 2001

Unlike existent field flow fractionation, new method, osmotic sink field flow fractionation is introduced and used ultrafiltration hollow fiber membranes as separation channel. This hollow fiber osmotic sink field flow fractionation is called HF-OSFFF. A theory that describes the retention, relaxation, resolution, plate number for the system, has been developed and experimentally verified by separation model of po1ystyrene latex beads. At external field, it is measured that radial flow rates change according to various concentrations of PEG solutions. Concentration of PEG solution vs. radial flow rate is a linear relation. For diameter distribution of unknown polymer sample, HF-OSFFF compared with the commercial capillary hydrodynamic flow fractionation (CHDF).

• Bulletin of the Korean Chemical Society
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• v.27 no.3
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• pp.413-418
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• 2006

Sodium hyaluronate (NaHA), water soluble polymer having ultra-high molecular weight, is characterized by using on-line frit inlet asymmetrical flow field-flow fractionation (FI-AFlFFF) and multiangle light scattering (MALS). This study demonstrates the capability of power programming FI-AFlFFF for the separation of NaHA and the applicability of FI-AFlFFF with MALS for the characterization of molecular weight distribution and their structural information. Since sample injection and relaxation in FI-AFlFFF are achieved by using hydrodynamic relaxation, separation of high molecular weight polymers can be achieved smoothly without halting the separation flow. Experiments are carried out with the two different NaHA products (a raw NaHA sample and a thermally degraded NaHA product) and molecular weight distribution and conformations in solution are determined. Influence of sample filtration on the change of molecular weight distribution is also discussed.

• Bulletin of the Korean Chemical Society
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• v.35 no.1
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• pp.69-75
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• 2014

Accurate analysis of fly ash particles is not trivial because of complex nature in physical and chemical properties. SPLITT fractionation (SF) was employed to fractionate the fly ash particles into subpopulations in large quantities. Then the SF-fractions were analyzed by the steric mode of sedimentation field-flow fractionation (Sd/StFFF) for size analysis. The SF-fractions were also analyzed by ICP-OES. The results showed that the fly ash is mainly composed of Fe, Ca, Mg and Mn. No particular trends were observed between the particle size and the concentrations of Fe, Ca, Mg, while Mn, Cu and Zn were in higher concentrations in smaller particles. Sample preparation procedures were established, where the fly ash particles were sieved to remove large contaminants, and then washed with acetone to remove organics on the surface of particles. The sample preparation and analysis methods developed in this study could be applied to other environmental particles.

• Bulletin of the Korean Chemical Society
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• v.22 no.4
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• pp.337-348
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• 2001

This article gives an overview of a recently developed channel system, frit-inlet asymmetrical flow field-flow fractionation (FI-AFlFFF), which can be applied for the separation of nanoparticles, proteins, and water soluble polymers. A conventiona l asymmetrical flow FFF channel has been modified into a frit-inlet asymmetrical type by introducing a small inlet frit near the injection point and the system operation of the FI-AFlFFF channel can be made with a great convenience. Since sample components injected into the FI-AFlFFF channel are hydrodynamically relaxed, sample injection and separation processes proceed without interruption of the migration flow. Therefore in FI-AFlFFF, there is no requirement for a valve operation to switch the direction of the migration flow that is normally achieved during the focusing/relaxation process in a conventional asymmetrical channel. In this report, principles of the hydrodynamic relaxation in FI-AFlFFF channel are described with equations to predict the retention time and to calculate the complicated flow variations in the developed channel. The retention and resolving power of FI-AFlFFF system are demonstrated with standard nanospheres and protreins. An attempt to elucidate the capability of FI-AFlFFF system for the separation and size characterization of nanoparticles is made with a fumed silica particle sample. In FI-AFlFFF, field programming can be easily applied to improve separation speed and resolution for a highly retaining component (very large MW) by using flow circulation method. Programmed FI-AFlFFF separations are demonstrated with polystyrene sulfonate standards and pululans and the dynamic separation range of molecular weight is successfully expanded.

• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2489-2492
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• 2007

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.312-313
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• 2006

The primary aim pursued by the preparation of separation membrane is the preparation of the membrane thin as well as with no defect. The field-flow fractionation deposition is a new molding technology which can overcome the traditional disadvantages such as multi-preparation to the preparation of great area of separation membrane with no defect. Therefor the mainly ingredients which influence the appearance and performance of titanium membrane layer are investigated by scanning electricity mirror (SEM) as well as porous material testing instrument: powder performance prepared and confected; selection of supporting body; sintering system such as temperature and time. It is shown that the membrane thickness can be controlled at $50{\mu}m$ or so; the filtration precision mainly rests with powder performance and selection of supporting body and little sintering system

• Bulletin of the Korean Chemical Society
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• v.24 no.9
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• pp.1339-1344
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• 2003

Flow field-flow fractionation (FlFFF) is a technology to separate the molecules by size in an open channel. Molecules with different size have different diffusivities and are located vertically in different positions when passing through an open channel. In this study, hollow fiber membranes instead of conventional rectangular channels have been used as materials for the open channel and this change would decrease the cost of manufacturing. FlFFF is a useful technique to characterize the biopolymeric materials. Retention time, diffusion coefficients and Stokes radius of analysis can be calculated from the related simple equations. Hollow-fiber flow field-flow fractionation (HF-FlFFF) has been used for the characterization and separation of protein mixture in a phosphate buffer solution and has demonstrated the potential to be developed into a disposable FlFFF channel. The important indexes for the analytical separation are selectivity, resolution and plate height. The optimized separation condition for protein mixture of Ovalbumin, Alcohol dehydrogenase, Apoferritin and Thyroglobulin is ${\dot V}_{out}/{\dot V}_{rad}=0.65/0.85\;mL/min$.

• Bulletin of the Korean Chemical Society
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• v.32 no.4
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• pp.1315-1320
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• 2011

Whey protein (WP) is a mixture of proteins, and is of high nutritional values. WP has become an important source of functional ingredients in various health-promoting foods. In this study, size-exclusion chromatography (SEC) and asymmetrical flow field-flow fractionation (AsFlFFF) were used for separation and analysis of whey proteins. It was found that a lab-prepared WP from raw milk is mostly of ${\beta}$-lactoglobulin with small amount of higher molecular weight components, while a commercial whey protein isolate (WPI) powder contains relatively larger amount of components other than ${\beta}$-lactoglobulin, including IgG and protein aggregates. Results suggest that AsFlFFF provides higher resolution for the major whey proteins than SEC in their normal operation conditions. AsFlFFF could differentiate the BSA and Albumin, despite a small difference in their molecular weights, and also was able to separate much smaller amount of aggregates from monomers. It is noted that SEC was able to show the presence of low molecular weight components other than the major whey proteins in the WP samples, which AsFlFFF could not show, probably due to the partial loss of those low molecular weight species through the membrane.

• Bulletin of the Korean Chemical Society
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• v.24 no.9
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• pp.1333-1338
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• 2003

Hollow Fiber flow field-flow fractionation (HF-FlFFF) has been tested in polyacrylonitrile (PAN) membrane channel in order to compare it with polysulfone (PSf) membrane channel. It has been experimentally shown that the separation time of 0.05-0.304 ${mu}m$ polystyrene latex (PSL) standards in PAN membrane channel is shorter than that in PSf channel by approximately 65%. The optimized separation condition in PAN membrane is ${\dot V}_{out}/{\dot V}_{rad}=1.4/0.12\;mL/min$, which is equal to the condition in PSf membrane channel. In addition both the resolution ($R_s$) and plate height (H) in PAN membrane channel are better than that in PSf membrane channel. The membrane radius was obtained by back calculation with retention time. It shows that the PSf membrane is expanded by swelling and pressure, but the PAN membrane doesn't expand by swelling and pressure.

• Bulletin of the Korean Chemical Society
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• v.33 no.2
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• pp.711-713
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• 2012