Chromatographic processes membrane chromatography

McCoy, B. J. 1991. Theory of affinity chromatography. In Chromatographic and Membrane Processes in Biotechnology (C. A. Costa and J. S. Cabral, eds.), pp. 115-135. Kluwer Academic Publishers, Dordrecht, The Netherlands. 

The lack of selectivity can be circumvented by coupling a postcolumn flow system to a liquid chromatograph. This has promoted the development of a number of efficient liquid chromatography-CL approaches [16, 17]. Eluted analytes are mixed with streams of the substrate and oxidant (in the presence or absence of a catalyst or inhibitor) and the mixed stream is driven to a planar coiled flow cell [18] or sandwich membrane cell [19] in an assembly similar to those of flow injection-CL systems. Many of these postcolumn flow systems are based on an energy-transfer CL process [20], In others, the analytes are mixtures of metal ions and the luminol-hydrogen peroxide system is used to generate the luminescence [21],... 

Membrane adsorbers derive from the technological developments in the membrane separation field and in column chromatography of proteins. They combine the high selectivity of chromatographic separations and the high productivity usually obtained in membrane separation processes. 

It is commonly assumed that transfer processes can be modeled by bulk phase thermodynamics and that surface or interfacial effects are negligible. These assumptions may, in the case of partitioning into amphiphilic structures formed by micelles or bilayer membranes, not always be appropriate. These interfacial solvents have a large surface to volume ratio, similar to interfacial solvents used in reversed-phase liquid chromatography. The partitioning into such phases is the basis of the chromatographic separation. 

In this section the methods developed in the previous section will be applied to analyze the dynamic behavior of integrated reaction separation processes. Emphasis is placed on reactive distillation and reactive chromatography. Finally, possible applications to other integrated reaction separation processes including membrane reactors and sorption-enhanced reaction processes will be briefly discussed. More details about reactive distillation processes were provided in Ref. [39]. For chromatographic reactors the reader should refer to Chapter 6 of this book, for sorption-enhanced reaction processes to Chapter 7, and for membrane reactors to Chapter 12. 

Poly(octadecylsiloxane) is often used in chromatography to prepare reversed phase column material. The process which takes place during a chromatographic run is closely related to the enrichment process described here i.e., materials which are employed to provide stationary phases for chromatography may also be used for preparing enriching membranes. This material gives rise to fewer absorption bands than PDMS but more than PE. 

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