Size exclusion chromatography Nuclear magnetic resonance

See also-. Bioassays Overview. Chemometrics and Statistics Multivariate Calibration Techniques. Infrared Spectroscopy Near-Infrared. Liquid Chromatography Size-Exclusion Liquid Chromatography-Mass Spectrometry Liquid Chromatography-Nuclear Magnetic Resonance Spectrometry. Pharmaceutical Analysis Drug... 

Ludlow, M., Louden, D., Handley, A., Taylor, S., Wright, B., and Wilson, I.D., Size-exclusion chromatography with on-line ultraviolet, proton nuclear magnetic resonance, and mass spectrometric detection and on-line collection for off-line Fourier transform infrared spectroscopy, /. Chromatogr. A, 857,89,1999. 

Various methods have been applied to the analysis of silicones in general, and these have been well summarised elsewhere [22]. In particular, size exclusion chromatography (SEC) [23], nuclear magnetic resonance... 

A structure-based approach for discovering protein ligands and for drug design by coupling size exclusion chromatography, mass spectrometry, and nuclear magnetic resonance spectroscopy. Anal. Chem. 2001, 73, 571-581. 

Because of polydisperse nature of HS, the importance of separation methods increased as the science evolved. Various separation methods were widely used for conventional fractionation and characterization of components based on differences in component solubility, charge, molecular weight, and/or size, polarity, hydropho-bicity, and so on (Janos, 2003). More recent research focused on advanced molecular-level analyses of humic mixtures (Hertkorn and Schmitt-Kopplin, 2007), in which a combination of separation techniques, mostly, chromatography, or capillary electrophoresis) were coupled with high-resolution instrumental analysis [e.g., mass spectrometry (MS) or nuclear magnetic resonance (NMR) spectroscopy]. Several examples appeared in the literature, including those that used size exclusion chro-... 

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. 

The application of UV spectrophotometers to the analysis of styrene containing copolymers has been extensively reported in the literature. However, hypochromic effects and band shifts which result in deviations from Beer s Law have limited the use of UV detectors as mass or composition detectors in size exclusion chromatography applications. Deviations from Beer s Law for low conversion styrene-acrylonitrile copolymers in tetrahydrofuran have been experimentally investigated and compared with results previously reported in the literature. The behaviour of the extinction coefficient as a function of the copolymer composition is discussed in view of the information obtained from infrared and nuclear magnetic resonance measurements on the same polymers. As a result of this investigation, a quantitative correlation of the extinction coefficients of styrene-acrylonitrile copolymers with the length of the styrene sequences has been obtained which, in turn, allows for the use of UV spectrophotometers as sequence length detectors. 

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