Aqueous size exclusion chromatography

Conductivity detectors, commonly employed in ion chromatography, can be used to determine ionic materials at levels of parts per million (ppm) or parts per bUHon (ppb) in aqueous mobile phases. The infrared (ir) detector is one that may be used in either nonselective or selective detection. Its most common use has been as a detector in size-exclusion chromatography, although it is not limited to sec. The detector is limited to use in systems in which the mobile phase is transparent to the ir wavelength being monitored. It is possible to obtain complete spectra, much as in some gc-ir experiments, if the flow is not very high or can be stopped momentarily. 

P.L. Dubin, Aqueous Size-Exclusion Chromatography, Elsevier, Amsterdam, 1988. ISBN 0444429573. 

An aqueous ethanol solution of acrylamide, 2,2 -methylenebisacrylamide as cross-linked agent and third acrylamide derivative, is dispersed in an n-alkane. Then three monomers are polymerized to spherical porous gels. The effect of the composition of the third monomer on the exclusion limits of the gel in size-exclusion chromatography has been investigated (82). 

The evolution of media covering aqueous and nonaqueous systems on the one hand and analytical as well as microscale and macroscale preparative applications on the other hand has resulted in an arbitrarily nomenclature within the field. Thus the current practice is to refer to the separation principle based on solute size as size exclusion chromatography (SEC) whereas the application in aqueous systems is traditionally referred to as gel filtration (GF) and the application in nonaqueous systems is designated gel-permeation... 

Hagel, L. (1988). Pore size distributions. In Aqueous Size-Exclusion Chromatography (P. Dubin, ed.), pp. 119-150. Elsevier, Amsterdam. 

Hagel, L. (1996). Characteristics of modern media for aqueous size exclusion chromatography. In Strategies in Size Exclusion Chromatography (M. Potschka and P. Dubin, eds.), ACS Symposium Series 635, pp. 225—248. Am. Chem. Society, Washington, DC. 

The packed columns of Shodex OHpak SB-800HQ series are packed with polyhydroxymethacrylate gels and are designed for use with high-resolution, high-speed aqueous size exclusion chromatography. The packed columns are best suited for the analysis of water-soluble polymers and proteins (Table 6.8). 

For the classical form of size exclusion chromatography in organic solvents, packings based on highly cross-linked styrene-divinylbenzene are used. For SEC of polar polymers using polar or aqueous solvents, packings based on a polar methacrylate polymer are used. Diol-derivatized silica is used for the separation of proteins and other polar polymers. The different packings will be discussed in sections dedicated to their different application areas. 

This section discusses in detail the column types that are available for the size exclusion chromatography of both polar and nonpolar analytes. It first discusses the various columns available for standard nonaqueous size exclusion chromatography. It then reviews the columns available for general size exclusion chromatography using aqueous mobile phases. Finally, it examines the columns designed for size exclusion chromatography of proteins and peptides. 

Solvent conversion of columns designed for aqueous size exclusion chromatography is rarely a problem. However, it should always be carried out at slow flow rates. For Ultrahydrogel columns, the recommended flow rate for a solvent conversion is below 0.3 ml/min. One should typically use 0.1 ml/min for most solvent conversion procedures. 

For the size exclusion chromatography of proteins on silica-hased diol packings, it is generally recommended to use fully aqueous mobile phases with a salt concentration between 0.1 and 0.3 M. In general, a phosphate buffer around pH 7 is used as the mobile phase. Under these circumstances, the tertiary structure of most proteins is preserved without difficulty and the interaction of proteins with each other is minimized. However, other inorganic buffers or combinations of buffers with organic solvents can be used without difficulties for special applications. 

ANALYTICAL AND PREPARATIVE COLUMNS FOR AQUEOUS SIZE EXCLUSION CHROMATOGRAPHY OF POLYSACCHARIDES... 

COMPARISON OF FOUR COMMERCIAL LINEAR AQUEOUS SIZE EXCLUSION COLUMNS AND FOUR SETS OF COMMERCIAL POLYETHYLENE OXIDE (PEO) STANDARDS FOR AQUEOUS SIZE EXCLUSION CHROMATOGRAPHY OF POLYVINYLPYRROLIDONE AND PEO... 

Chemically attached copolymers of iV-vinylpyrrolidone (N-VP) and N-(2-hydroxyethyl)acrylamide (N-HEAA) steeply decrease the inherent glass adsorp-tivity which is observed for proteins in aqueous buffer solutions. Thus, it became possible to apply the prepared materials to the size exclusion chromatography of viruses and ribosomes. 

Application of aqueous size-exclusion chromatography to carbohydrates a case history... 

Garcia, R., Porcar, I., Campos, A., Soria, V. and Figueruelo, J. E., Solution properties of polyelectrolytes. X. Influence of ionic strength on the electrostatic secondary effects in aqueous size-exclusion chromatography, /. Chromatogr. A, 662, 61, 1994. 

Dubin, P. L. and Principi, J. M., Hydrophobic parameter for aqueous size exclusion chromatography gels, Anal. Chem., 61, 780, 1989. 

PL Dubin, JM Principi. Hydrophobicity parameter of aqueous size exclusion chromatography gels. Anal Chem 61 780-781, 1989. 

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