Exclusion liquid chromatography

The packing material for liquid chromatography is produced from styrene and divinylbenzene dissolved in 50 to 300% by weight of organic solvent to both monomers. The constitution of divinylbenzene in the monomer mixture is not less than 60% by weight. In gel-permeation chromatography, the exclusive molecular weight is not less than 1 X 10 in terms of standard polystyrene (79). 

ASTM D-3536-91, Standard Test Method for Molecular Weight Averages and Molecular Weight Distribution by Liquid Exclusion Chromatography (Gel Permeation Chromatography-GPC), ASTM Annual Books of ASTM Standards, Vol. 08.02, P. 349—359. This method was deleted in the 1997 edition of the ASTM book. 

James, H. L., Gaylor, V. F., Anthony, N. R., "The Use of Liquid Exclusion Chromatography for Rapid Measurement of Gel in Styrene-Butadiene Elastomers," presented at the 1975 Gel Permeation Chromatography Seminar, Pittsburg, Pennsylvania (October, 1975). 

Dawkins, J. V. and Yeadon, G., Macromolecular separations by liquid exclusion chromatography, Farad. Symp. Chem. Soc., 15, 127,1980. 

Bly, D. D., Yau, W. W., and Stoklosa, H. J., Siphon counter techniques for minimizing molecular weight errors caused by flow-rate variation in high performance liquid exclusion chromatography, Anal. Chem., 48, 1256, 1976. 

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. 

M De Paoli, TM Barbina, R Mondini, A Pezzoni, A Valentino. Determination of organophosphorus pesticides in fruits by on-line size-exclusion chromatography-liquid chromatography-gas chromatography-flame photometric detection. J Chromatogr 626 145-150, 1992. 

With the advent of advanced characterization techniques such as multiple detector liquid exclusion chromatography and - C Fourier transform nuclear magnetic resonance spectroscopy, the study of structure/property relationships in polymers has become technically feasible (l -(5). Understanding the relationship between structure and properties alone does not always allow for the solution of problems encountered in commercial polymer synthesis. Certain processes, of which emulsion polymerization is one, are controlled by variables which exert a large influence on polymer infrastructure (sequence distribution, tacticity, branching, enchainment) and hence properties. In addition, because the emulsion polymerization takes place in an heterophase system and because the product is an aqueous dispersion, it is important to understand which performance characteristics are influended by the colloidal state, (i.e., particle size and size distribution) and which by the polymer infrastructure. 

Blom KF, Larsen BS, McEwen CN, Determining affinity-selected ligands and estimating binding affinities by online size exclusion chromatography/liquid chromatography-mass spectrometry, J. Comb. Chem., 1, 82-90, 1999. 

Bibliography on Liquid Exclusion Chromatography, ASTM AMD-40 and AMD-40-S1, American Society for Testing and Materials, Philadelphia, 1972 and 1975. 

This book covers some of the significant advances in hyphenated chromatographic separation methods for polymer characterization. Chromatographic separation techniques in this volume include size-exclusion chromatography, liquid chromatography, and field flow fractionation methods that are used in conjunction with information-rich detectors such as molecular size-sensitive or compositional-sensitive detectors or coupled in cross-fractionation modes. 

Patrick, D.W. Strand, D.A. Cortes, H.J. Automation and optimization of multidimensional microcolumn size exclusion chromatography-liquid chromatography for the analysis of photocrosslinkers in Cyclotene 400 series advanced electronic resins. J. Sep. Sci. 2002, 25, 519-526. 

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. 

HPLC-SEC High Pressure/Performance Liquid Chromatography Size Exclusion Chromatograph) ... 

Size exclusion effects can influence the measurement of chromatographic parameters in all types of liquid chromatography. Size exclusion effects occur because of the existence of pores in the stationary phase which are filled with mobile phase and are too small for large sample molecules to enter. The efficiency of the column is clearly influenced by these effects as the rate of equilibration between the mobile and stationary phases depends on the rate of diffusion of the sample molecules into the pores. As the length of the alkyl chain attached to the particles constituting the stationary phase is increased, the rate of diffusivity into the pores is decreased due to restricted access. It is thus clear that an optimum situation must be achieved whereby the access of the sample molecules to the stationary phase is... 

Kiparissides et al. [36] used liquid exclusion chromatography to study the dynamics of the continuous emulsion polymaization of vinyl acetate. 

Hi h Pressure Liquid Chromatography. Size exclusion chromatography was performed isocratically in 0.2 M ammonium acetate (flow-1.5 ml/min) with a Water s Model 840 HPLC with a Toyo-Soda G2000SWXL column (30 cm x 7.8 mm). Eluting components were monitored in the UV at 214 nm and by fluorescence (Ex - 230 nm, Em - 300 nm) and collected in 4 minute fractions for bioassay. Reverse phase chromatography was conducted with a Hewlett-Packard Model 1090 HPLC equipped with a Vydac C-18 column using a linear gradient over one hr from 10% to 50% acetonitrile in 0.1% TFA. Sample was monitored with a diode array detector from 190 to 350 nm in the UV. 

There is another packed column technique, referred to as porous HDC, or simply liquid exclusion chromatography or EEC, which has also been applied to particle size analysis. In this case the hardware nearly exactly duplicates that used for bulk polymers. Although the elution volume range is enhanced with these systems, the rather excessive band-spreading which results severely limits the resolution and therefore the practical use of the technique. 

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