Size exclusion chromatography chromatograms

Examples of the application of size-exclusion chromatography to the analysis of proteins. The separation in (a) uses a single column that in (b) uses three columns, providing a wider range of size selectivity. (Chromatograms courtesy of Alltech Associates, Inc. Deerfield, IL). 

Size-exclusion chromatography can be carried out using conventional HPLC instrumentation, replacing the HPLC column with an appropriate size-exclusion column. A UV/Vis detector is the most common means for obtaining the chromatogram. 

Size exclusion chromatography (SEC) separates molecules of a polymer sample on the basis of hydrodynamic volume. When the chromatograph is equipped only with a concentration-sensitive detector, i.e. conventional SEC, a molecular weight distribution (MWD) can be obtained from the chromatogram only through use of a calibration function relating molecular weight and elution volume V (2). 

Size exclusion chromatography (SEC) polymer elution profiles yield information regarding the molecular size distributions of polydisperse macromolecules. Polymer molecular weight distribution (MWD) represents an intrinsic property which provides direct correlation with many end-use physical properties and a universal criterion for polymer characterization (1). In order to convert elution profiles or chromatograms into MWD information proper calibration methods are required. SEC molecular weight calibration techniques represent experimental approaches for transformation of polymer elution profiles into MWD information and are dependent upon instrumentation, columns, and the polymer/solvent system under study. 

The size exclusion chromatography for this study was done in the routine manner execept for the inclusion of an online viscosity detector called a Differential Viscometer <3> (Viscotek Corp., Porter, Texas, USAl. This instrument together with an RI concentration detector permits the calculation of intrinsic viscosities across the chromatogram. An IBM PC data system with software is also provided (5). The software acquires data from both detectors, and performs calculations of intrinsic viscosity and molecular weight distributions using the Universal Calibration Method. 

Figure 8. Three-dimensional chromatogram of a commercial surfactant. Instrumental conditions size-exclusion chromatography, Microporasil GPC 60 A, 10% water and 90% methanol (v/v) at 1.0 mL/min. Detection was at 200-400 nm with a Hewlett-Packard Model...

Size exclusion chromatography (SEC) was used to determine the molecular weight and chain length properties of functionalized polymers 3a-3d with reference to polystyrene standards (Fig. 1). The SEC chromatograms of the products have... 

In ideal size-exclusion chromatography (SEC), fractionation is exclusively by hydrodynamic volume. Due to axial dispersion, however, a whole distribution of hydrodynamic volumes (and, therefore, of molecular weights) is instantaneously present in the detector cell. Under these conditions, it is assumed that the mass chromatogram w(V) (i.e., the instantaneous mass w versus the elution time or elution volume V) is a broadened version of a true (or corrected) mass chromatogram w V), as follows [1] ... 

Determination of the average chemical composition and polymer composition by size-exclusion chromatography (SEC) has been reported in the literature. Two different types of concentration detector or two different absorption wavelengths of an ultraviolet or an infrared detectors are employed the composition at each retention volume is calculated by measuring peak responses at the identical retention points of the two chromatograms. 

Figures 32-14 and 32-15 illustrate typical applications of. size-exclusion chromatography. In the chromatograms shown in Figure 32-14, a hydrophilic packing was used to exclude molecular weiuhts greater than 1000. Several sugars in canned...

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