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Difference between revisions of "Field-Flow fractionation (FFF)"
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Field-Flow fractionation (FFF) (view source)
Revision as of 14:26, 2 September 2021
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===Asymmetric flow FFF (AF4)=== | ===Asymmetric flow FFF (AF4)=== | ||
[[File:AFFFF channel.svg|thumb|Illustration of a separation channel for asymmetric flow field-flow-fractionation.]] | [[File:AFFFF channel.svg|thumb|Illustration of a separation channel for asymmetric flow field-flow-fractionation.]] | ||
The asymmetric flow FFF (AF4) is realised in a separation channel where an separation force ist generated in form of an asymmetric crossflow through a semipermeable membrane. Through the cross-flow larger particles accumulate at the channel bottom while smaller particles accumulate at the | [[File:FFF Separation Mechanism.webm|thumb|Animation of the AF4 separation driven by particle diffusion in a parabolic flow profile. Particles colored in red are the smaller and particles colored in blue are the larger ones. The force applied on the top is the crossflow (indicated by the arrows on the bottom). The elution flow in longitudinal direction is shown with the flow arrows indicating the velocity profile.]] | ||
The asymmetric flow FFF (AF4) is realised in a separation channel where an separation force ist generated in form of an asymmetric crossflow through a semipermeable membrane. Through the cross-flow larger particles accumulate at the channel bottom while smaller particles accumulate more at the upper part induced by diffusion. The injected particles can be eluted through a parabolic flow-profile in combination with the reduction of the crossflow. | |||
=== Centrifugal FFF === | === Centrifugal FFF === | ||
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 at the | 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 === | ||