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Difference between revisions of "Field-Flow fractionation (FFF)"
Field-Flow fractionation (FFF) (view source)
Revision as of 14:41, 31 January 2022
, 14:41, 31 January 2022→Process and technologies
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| Product = Biomass in different physicochemical fractions | | Product = Biomass in different physicochemical fractions | ||
|Name=Field-Flow fractionation|Category=Separation technologies}} | |Name=Field-Flow fractionation|Category=Separation technologies}} | ||
<onlyinclude>'''Field-Flow Fractionation (FFF)''' is a | <onlyinclude>'''Field-Flow Fractionation (FFF)''' is a family of high resolution separation techniques especially applicable to macromolecules colloids and particles, and shares the most common likeness with liquid [[chromatography]] (LC). The mechanism for separation, however, does not involve interactions with a stationary phase used in LC methods. Instead, a field is applied normal to a laminar flow through a narrow channel, which reslts in a parabolic flow profile, separating different analytes into distinct regions of the velocity profile. The analytes can be fractionated according to their physicochemical properties such as charge, chemical composition, density, molar mass, and size. Beside analytical purposes the FFF can also be utilised for preparative purposes. | ||
==Feedstock== | ==Feedstock== | ||
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==Process and technologies== | ==Process and technologies== | ||
Different variants of the FFF are available | Different variants of the FFF are available, which includes Asymmetric flow FFF (AF4), centrifugal FFF, electrical FFF (EFFF), split flow thin-cell fractionation (SPLITT), and thermal FFF. Depending on the applied technology particles can be separated in dependence of different physicochemical properties. | ||
===Asymmetric flow FFF (AF4)=== | ===Asymmetric flow FFF (AF4)=== | ||
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In centrifugal FFF the separation force is realised via an centrifugal field. Through the induced gravitational field larger particles accumulate at the channel bottom while smaller particles accumulate more at the upper part. The injected particles can be eluted through a parabolic flow-profile in combination with the reduction of the centrifugal field. Due to the large range of applicable centrifugal force the method has its advantage to separate a wide range of different sized particles (usually µm-nm range). | In centrifugal FFF the separation force is realised via an centrifugal field. Through the induced gravitational field larger particles accumulate at the channel bottom while smaller particles accumulate more at the upper part. The injected particles can be eluted through a parabolic flow-profile in combination with the reduction of the centrifugal field. Due to the large range of applicable centrifugal force the method has its advantage to separate a wide range of different sized particles (usually µm-nm range). | ||
=== Electrical FFF === | === Electrical FFF (EFFF) === | ||
This technology combines the FFF with an electrical field as additional separation force. Besides the separation based on particle size this method adds the capability to separate particles/molecules in dependence of their charge. | This technology combines the FFF with an electrical field as additional separation force. An electrical voltage is imposed between the top and bottom walls. Charged particles migrate toward either wall according to their electrophoretic mobility, which is determined by their sizes and charge densities, and undergo different flow velocity.<ref>{{Cite book|author=T. Okada|year=2007|section_title=Field Flow Fractionation: Electric Fields|book_title=Encyclopedia of Separation Science|publisher=Academic Press}}</ref> Besides the separation based on particle size this method adds the capability to separate particles/molecules in dependence of their charge. EFFF is well suited to the fractionation of proteins and measuring protein adsorption on to surfaces.<ref>{{Cite book|author=R. Hecker, H. Colfen|year=2000|section_title=PROTEINS/Field Flow Fractionation|book_title=Encyclopedia of Separation Science|publisher=Academic Press}}</ref> | ||
=== Split flow thin-cell fractionation (SPLITT) === | === Split flow thin-cell fractionation (SPLITT) === | ||