Partitioned phases, applications

This study was initiated to explore the applications of partitioned phases to separations of therapeutically active materials. Posssibilities include 1 ) isolation and purification of one component from a complex mixture (e.g. alpha-1 antitrypsin, immunoglobulins from plasma sources or tissue culture broth), 2) removal of a secondary product or contaminant (e.g. DNA, residual PEG from a process stream) and 3) simultaneous fermentation and isolation of product from cellular components. 

Lee, K. H., Lombardo, M., and Sandler, S. I. (1987). The Generalized van der Waals Partition Function Application to Square-Well Fluids. Fluid Phase Equilib. 21,177. 

The method possesses only a modest sensitivity, if flame ionization GC is used. However, if a mass spectrometer focussed on the appearance of the ion with mass 91 is available as a GC monitor, amphetamine concentrations of 100 ng per ml and methyl amphetamine concentrations as low as 10 ng per ml of body fluid can still be detected. Fig. 2 gives an example of an application, the analysis of the urine of a doped competitive cyclist. Polyethylene imine was used as a partition phase, the appearance of ion 91 recorded. The intensities of the 3 single mass recordings differ by factors of 10. The retention time corresponds to amphetamine. 

H. Walter, D. E. Brooks, and D. Eisher, eds.. Partitioning in Mqueous Tiro-Phase Systems Theory, Methods, Uses and Applications to Biotechnology, Academic Press, Inc., Orlando, 1985. 

On the subject of applications of such experimental parameters, the questions of whether an ionized molecule may or may not partition into octanol and whether bulk-phase partitioning is in turn adequate to describe bilayer partitioning are important and pertinent ones, and are addressed in Section 16.3. 

A cosolvent used as a miscible additive to CO2 changed the properties of the supercritical gas phase. The addition of a cosolvent resulted in increased viscosity and density of the gas mixture and enhanced extraction of the oil compounds into the C02-rich phase. Gas phase properties were measured in an equilibrium cell with a capillary viscometer and a high-pressure densitometer. Cosolvent miscibility with CO2, brine solubility, cosolvent volatility, and relative quantity of the cosolvent partitioning into the oil phase are factors that must be considered for the successful application of cosolvents. The results indicate that lower-molecular-weight additives, such as propane, are the most effective cosolvents to increase oil recovery [1472]. 

Although the Lewis cell was introduced over 50 years ago, and has several drawbacks, it is still used widely to study liquid-liquid interfacial kinetics, due to its simplicity and the adaptable nature of the experimental setup. For example, it was used recently to study the hydrolysis kinetics of -butyl acetate in the presence of a phase transfer catalyst [21]. Modeling of the system involved solving mass balance equations for coupled mass transfer and reactions for all of the species involved. Further recent applications of modified Lewis cells have focused on stripping-extraction kinetics [22-24], uncatalyzed hydrolysis [25,26], and partitioning kinetics [27]. 

As will be described in detail below, solute distribution in biphasic systems can be modulated by application of a Galvani potential difference across the interface, thereby leading to the transfer of species from one phase to the other. Therefore, in electrochemical terms, passive transfer simply means the partition across an interface, mediated by a potential-driven process. 

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