Liquid exclusion adsorption

Trathnigg, B., Kollroser, M., Rappel, C. (2001). Liquid exclusion adsorption chromatography, a new technique for isocratic separation of nonionic surfactants. III. Two-dimensional separation of fatty alcohol ethoxylates. J. Chromatogr. A 922(1-2), 193-205. 

Trathnigg B. Liquid exclusion—adsorption chromatography new technique for iso-cratic separation of nonionic surfactants, 11. Quantitation in the analysis of fatty alcohol ethoxylates. J Chromatogr A 2001 915 155. 

The principle of the liquid chromatography under critical conditions (LC CC) was elucidated in Section 16.3.3. The mutual compensation of the exclusion—entropy and the interaction—enthalpy-based retention of macromolecules can be attained when applying in the controlled way the interactions that lead to either adsorption or enthalpic partition. The resulting methods are called LC at the critical adsorption point (LC CAP) or LC at the critical partition point (LC CPP), respectively. The term LC at the point of exclusion-adsorption transition (LC PEAT) was also proposed for the procedures employing compensation of exclusion and adsorption [161]. It is anticipated that also other kinds of enthalpic interactions, for example the ion interactions between column packing and macromolecules can be utilized for the exclusion-interaction compensation. 

Modern liquid chromatography can be carried out in any of the classical modes, e.g., liquid-solid adsorption chromatography, liquid-liquid partition chromatography, reversed-phase chromatography, ion-exchange chromatography, and gel-permeation (size exclusion) chromatography. 

LC-PEAT Liquid chromatography at the point of exclusion-adsorption transition... 

LC-TEA Liquid chromatography at the theta exclusion-adsorption condition... 

The chromatographic separation of polymers by liquid chromatography under critical conditions (LCCC), also referred to as liquid chromatography (LC) at the critical point of adsorption, LC in the critical range or LC at the point of exclusion-adsorption transition, has attracted significant attention within polymer community. Russian scientists using TLC [1-3] and later LC [4,5] have been the first experimentally identify critical conditions. At the critical conditions polymers of a given kind are eluted independently from their molar mass (for example. Fig. 1 [6]). 

FIGURE 5.3 LCCC chromatogram of functionalized polystyrenes. Source Reprinted from K. Baran, S. Laugier, H. Cramail, Fractionation of functional polystyrenes, polyCetkylene oxide)s and poly(styrene)-b-poly(ethylene oxide) by liquid chromatography at the exclusion-adsorption transition point, Journal of Chromatography B, 753 (2001) 139, (2001), used with permission from Elsevier (Ref. [17]). 

Thin-layer chromatography (TLC) Silica, cellulose, ion-exchange resin, controlled porosity solid Liquid Planar Adsorption (partition, ion-exchange, exclusion)... 

Macromolecular Chemistry Physics 200, No.9, 1999, p.2074-9 INVESTIGATION OF MOLECULAR DIMENSIONS OF POLYSTYRENE AS A FUNCTION OF SOLVENT COMPOSITION APPLICATION TO LIQUID CHROMATOGRAPHY AT THE EXCLUSION-ADSORPTION TRANSITION POINT Baran K Laugier S Cramail H ENSCPB... 

Liquid chromatography was used to study PS standards at the exclusion-adsorption transition point using silica... 

Principle The adsorptive-bubble separation methods, or adsub-ble methods for short [Lemlich, Chem. Eng. 73(21), 7 (1966)], are based on the selective adsorption or attachment of material on the surfaces of gas bubbles passing through a solution or suspension. In most of the methods, the bubbles rise to form a foam or froth which carries the material off overhead. Thus the material (desirable or undesirable) is removed from the liquid, and not vice versa as in, say, filtration. Accordingly, the foaming methods appear to be particularly (although not exclusively) suited to the remov of small amounts of material from large volumes of hquid. 

Principles and Characteristics Liquid chromatography is the generic name used to describe any chromatographic procedure in which the mobile phase is a liquid. It may be classified according to the mechanism of retention in adsorption, partition, size-exclusion, affinity and ion-exchange (Scheme 4.4). These mechanisms form the basis for the chromatographic modes of... 

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