Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Ultrafiltration dilution factor

Ultrafiltration (UF) and diafiltration (DF) are very popular methods for conditioning the clarified culture broth for chromatography. As general rule, dilute animal cell culture supernatants are concentrated up to a factor of 20 and even more prior to fractionation. Ultrafiltration is a process in which a solution containing macromolecules is passed across a functional membrane, while macromolecules are retained by the membrane. The process is driven by the pressure drop across the membrane also called transmembrane pressure (PT) expressed as... [Pg.553]

Several factors can affect the retention properties of the membrane and some of these will be discussed here. During ultrafiltration the transport of solute to the surface of the filter Is faster than the rate at which permeation through the membrane occurs. This is further complicated, as ultrafiltration progresses, by an increase in the concentration of retained molecules at the membrane. Both events contribute to the phenomenon called concentration polarization. This effectively introduces a second layer of membrane , and as a consequence the retention characteristics of the system are altered. The build-up of solute can be reduced by introducing some form of agitation at the filter surface. However. this procedure does not seem to be effective against the gel-type layers formed by proteins. Various procedures have been suggested to slow down this build-up of solute the solution can be diluted with an appropriate solvent the ultrafiltration process can be interrupted and the flow reversed momentarily a low operation pressure could be used. [Pg.203]

Figure 1. GPC chromatogram (left side) and taste dilution (TD) factors for sweetness (right side) of the low molecular weight fraction (MW Figure 1. GPC chromatogram (left side) and taste dilution (TD) factors for sweetness (right side) of the low molecular weight fraction (MW<I kDa) isolated from de-fatted beef bouillon by means of ultrafiltration...
In ultrafiltration, analyte molecules are basically carried along with the flow of water and electrolytes. The factors determining recovery in ultrafiltration are membrane characteristics, temperatme, and chemistry of the analyte. Unlike microdialysis, recovery is not dependent on flow rate, membrane surface area, or probe size. Recovery tends to be higher than for dialysis, since there is no perfusion medium to dilute the collected analyte. Ultrafiltration recovery rates are typically in the 90-100% range. This high recovery rate simplifies determination of in vivo analyte concentrations. Table I illustrates some in vitro recoveries obtainable with ultrafiltration probes. [Pg.187]


See other pages where Ultrafiltration dilution factor is mentioned: [Pg.216]    [Pg.211]    [Pg.505]    [Pg.224]    [Pg.242]    [Pg.987]    [Pg.161]    [Pg.199]    [Pg.987]    [Pg.463]    [Pg.865]    [Pg.987]   
See also in sourсe #XX -- [ Pg.472 , Pg.572 ]




SEARCH



Ultrafiltrate

© 2024 chempedia.info