Separation size-exclusion chromatography

Hutchens, T. W., Gibbons, W. E., Besch, P. K. (1984). High-performance chromatofocusing and size-exclusion chromatography - separation of human uterine estrogen-binding proteins. J. Chromatogr. 297, 283-299. 

Moore and Jorgenson combined the rapid two-dimensional separation achieved by LC-CZE with SEC to make the first comprehensive three-dimensional separation involving an electrodriven component in 1995. Size exclusion chromatography separated the analytes over a period of several hours while the reverse phase HPLC-CZE combination separated components in only 7 min. A schematic diagram of the three-dimensional SEC-reverse phase HPLC-CZE instrument is shown in Figure 9.9 (18). A dilution tee was placed between the SEC column and the reverse phase HPLC injection loop in order to dilute the eluent from the SEC column, since it contained more methanol than was optimal for the reverse phase HPLC column. 

Since size exclusion chromatography separates polymer molecules by their size (especially hydrodynamic size), plotting the molecular size vs. the retention volume should be universal, regardless of the polymer molecular weight. The universal calibration curve is given as ... 

The advent of size exclusion chromatography in the 1960 s provided an alternative to drying polymer-polymer-solvent samples to determine the equilibrium phase compositions. Size exclusion chromatography separates solvents from polymers and to a varying extent, polymers from polymers, based on the size of the molecules in solution. Ultraviolet spectrometry and refractive index detectors may be used to determine the concentrations of each of the polymers in each of the phases (Lloyd et al., 1980). 

Size-exclusion chromatography separates hiomolecules on the basis of their relative molecular size, where molecules are eluted in order of decreasing size. 

Briefly describe how SEC (size exclusion chromatography) separates polymers according to size. Explain how the universal calibration curve can be used to determine molecular weight. 

Size-exclusion chromatography separates molecules by size, i.e. according to molecular mass. The largest molecules are eluted first and the smallest molecules last. This is the best method to choose when a mixture contains compounds with a molecular mass difference of at least 10%. 

Size exclusion chromatography Separation by size (larger molecule elutes faster) purity analysis ... 

Size-exclusion chromatography separation differs significantly fh)m other HPLC methods. For example, retention in SEC corresponds generally to values of k < 0. Similarly, there is no stationary phase apart from the stagnant mobile pha.se within the particle pores. Therefore there is no diffusion williin (he stalioniiry phase D, 0). This leads to equations for band broadening in SEC of a somewhat different form. 

Benoit and coworkers (15) showed that size exclusion chromatography separates polymer molecules by hydrodynamic volume. The hydrodynamic volume can be expressed as the product of intrinsic viscosity and molecular weight ... 

Size-exclusion chromatography separates solutes on the basis of their size. The stationary phase consists of a polymer matrix of various pore sizes. Solutes are separated according to their ability to penetrate the polymer matrix. The small solutes penetrate more and lag behind the larger solutes. 

Size exclusion chromatography separates molecules according to their size in solution. As a sample passes through the column, molecules which are too large to penetrate the pores of the packing are excluded and remain in the interparticle volume, Vq (this is also called the void or interstitial volume and is not to be confused with the solvent elution time Iq normally encountered in other forms of liquid chromatography). These molecules are eluted first from the column at the point of total exclusion. Small molecules which can permeate all the pores elute at the solvent front or total solvent volume F. This is the point of total permeation. Molecules of intermediate size will penetrate... 

Size exclusion chromatography separation of this 16-component star-block copolymer revealed four partially resolved peaks (Fig. 9.21). They correspond to the four molar masses of the sample consisting of species with one to four arms. The molar masses are defined by the number of arms and are M-2M-3M-4M. Despite appropriate resolution, the SEC chromatogram did not give any indication of the complex chemical structure of the sample. 

Kilz P. Methods and columns for high-speed size exclusion chromatography separations. In Chi-san Wu, editor. Handbook of Size Exclusion Chromatography and Related Techniques. 2nd ed. New York Dekker 2003. p 561. 

By contrast with other chromatographic methods, GPC (gel permeation chromatography) or SEC (size exclusion chromatography) separates according to the size of the specimen molecule in solution. This is a simple way of utilizing the exclusion principle. This very specific separation mechanism enables the determination of molecular weight distribution and dispersion index. 

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