Open column partition

Column Open column Descending Adsorption, partition, ion exchange, size exclusion... 

Partition chromatography Ion exchange chromatography Paper chromatography Open-column chromatography High-performance liquid chromatography... 

Open-column chromatography with silica gel and alumina is not applicable to the fractionation of tanins because of their strong binding to these adsorbents, which induces extensive loss of tannins. Such losses do not occur with countercurrent chromatography, as it does not use a solid stationary phase. Such molecules are very polar, so butanol-based solvent systems can be used. Centrifugal partition chromatography is more adequate in this case, as compared to hydrodynamic CCC, because of the good retention of the stationary phase of a such solvent system. 

Countercurrent chromatography (CCC) is a support-free liquid-liquid partition system in which solutes are partitioned between the mobile and stationary phases in an open-column space. The instrumentation, therefore, requires a unique approach for achieving both retention of the stationary phase and high partition efficiency in the absence of a solid support. A variety of existing CCC systems may be divided into two classes [1] (i.e., hydrostatic and hydrodynamic equilibrium systems). The principle of each system may be illustrated by a simple coil as shown in Fig. 1. 

Partition chromatography is based on the ability of solutes to distribute between two liquid phases. In open-column chromatography, one of the liquid... 

The type, if any, of open-column, flash, or vacuum-column chromatography used. These were divided into silica gel bonded phases (e.g, ODS, C-8, Diol, CN) or gel permeation on nonfunctionalized resins, including both size and partition chromatography systems (e.g., Sephadex LH-20, Sephadex LH-60, NS Gels, BioBeads SX-2, SX-4, SX-8, AMBERLITE XAD-2, XAD-4, and XAD-7, TSK-G3000S gel). 

Our method for the quantitative analysis of lAA consists of four major steps 1) extraction, 2) prepurification, 3) HPLC, and 4) GC-MS. The major time-consuming steps are the purification steps prior to GC-MS. The traditional prepurification [1, 11] has involved solvent partitioning steps and, in some protocols, open column liquid chromatography. Use of high resolution bonded phase capillary GC columns has allowed increased sensitivity at the mass spectral step, and the use of 3 and 5 /xm HPLC packings has made it reasonable to use shorter columns, thus reducing the time required for HPLC. The improvement in recovery afforded by the shorter HPLC columns and the improved sensitivity of capillary GC-MS suggested to us that it was possible to scale down the sample size to a level that made practical the use of Sep-Pak-Mko disposable mini-columns for sample preparation [2, 6, 7]. 

A one oc sample of the fuel gas to be analyzed is iq jected into a gas chromatograph where it is passed through a 60 meter, megabore, thick film, methyl silicone liquid phase, open tubular partitioning column, and separated into its individual constituents. 

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