Multistage chromatography

The selection of the right gel-permeation chromatography (GPC) column or column combination for a special task is a multistage procedure. First, a decision about the type of column has to be made according to the polymer samples in question ... 

M. J. M. Wells, Off-line multistage extraction chromatography for ultra-selective herbicide residue isolation, in Proceedings of the 3rd Annual International Symposium on Sample Preparation and Isolation Using Bonded Silicas, Analytichem International, Harbor City, CA, 1986, pp. 117-135. 

Liquid-liquid partition chromatography was invented by A. J. P. Martin and R. M. L. Synge in 1941. Martin had earlier devised a multistage solvent extraction process for the separation of vitamin E, although this work was not published. He and Synge then... 

Transport of metals in the environment is critically dependent on speciation. Often metals are associated with colloidal materials, fulvic acid, or humic acid. Extensive research is ongoing to study the uptake capacity of these materials as well as minerals, the distribution of elements in natural water samples, and species-dependent means of remediation. Speciation of yttrium and lanthanides in natural water has been reported [415] using size exclusion chromatography and ICP-MS. Multistage filtration has also been used with ICP-MS measurement of the separated fractions [416]. Kinetic studies of metal uptake rate as a function of EDTA, NTA, and fulvic acid concentrations in the water have been described [417]. 

MD (multistage, multicolumn) chromatography was early discovered to be a powerful tool for separating complex mixtures [8]. Two of the protagonists were J. C. Giddings [9,10] and J. F. K. Huber [11]. MD-LC is based on coupling columns in an online or offline mode, which are operated in an orthogonal... 

The main limitation of the technique is the problem of achieving radiochemical, as distinct from chemical, purification of the final labeled product. Purification of the irradiated sample is necessary to remove radiation-induced degradation products and labile tritium. Many of the degradation products are not only chemically similar to the parent compound, but also possess much higher specific activities. For complete purification it is necessary to use multistage processes, such as gas and column chromatography, countercurrent distribution, and fractional distillation. Distribution of isotope within a molecule is generally random and nonuniform however, in some circumstances useful specificity can be achieved.17... 

The partitioning of a substance between two liquid phases (multistage partitioning, partition chromatography) and the extraction of solids require similar properties of a solvent [50-55]. When a substance has to be partitioned, a solvent system with limited miscibility of the components is required in order that the substance dissolves to a different extent in the two phases. The greater the chemical differences between any two solvents, the more limited their miscibility. Other requirements that the solvent system must fulfil are, inter alia, a favorable partition coefficient (the average partition coefficient of the component mixture should be between ca. 0.2 and 5), as high a separation... 

Multidimensional (multistage, multicolumn) high-performance liquid chromatography (MD-HPLC) offers the possibility of cutting the elution profiles into consecutive fractions, where these fractions can be treated... 

Ito, Y. Zhang, T. Y. "Multistage mixer-settler planet centrifuge Preliminary studies on partition of macromolecules with organic-aqueous and aqueous two-phase solvent systems" /. Chromatography. 1988, 437, pp 121-129. 

Loftus, N. et al., Profiling and biomarker identification in plasma from different Zucker rat strains via high mass accuracy multistage mass spectrometric analysis using liquid chromatography/mass spectrometry with a quadrupole ion trap-time of flight mass spectrometer, Rapid Commun. Mass Spectrom., 22(16), 2547, 2008. 

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