Ion-exchange chromatography application

Gel filtration is a rapid and efficient alternative to dialysis for desalting and buffer exchange. It is used, for example, in the preparation of protein samples prior to freeze drying or fractionating by ion exchange chromatography. Applications include ... 

In this section ion exchange chromatography applications in biochemistry are documented according to the substances to be separated, isolated or studied. A broader and more detailed survey of many substances of biochemical interest separated by chromatographic methods can be found in a comprehensive book on LC edited by Deyl et al. [214]. Nevertheless, some reviews and novel original references are given here. (See Note following References, p. 269.)... 

Examples of the application of ion-exchange chromatography to the analysis of (a) inorganic anions, (b) inorganic cations, (c) antifreeze, and (d) vitamins. (Chromatograms courtesy of Alltech Associates, Inc. Deerfield, IL). 

A feature of ion exchange chromatography is, of course, that ionic solutions are used as eluants, so that the eluted species are present in an electrolyte background. The problem which now arises in the application of electrical... 

Adsorption and ion exchange chromatography are well-known methods of LC. In adsorption, one frequently selects either silica or alumina as stationary phase for separation of nonionic, moderately polar substances (e.g. alcohols, aromatic heterocycles, etc.). This mode works best in the fractionation of classes of compounds and the resolution of isomeric substances (J). Ion exchange, on the other hand, is applicable to the separation of ionic substances. As to be discussed later, this mode has been well developed as a tool for analysis of urine constituents (8). 

Hence, once a B ion is freed from the resin, it is immediately complexed and there is much less tendency for it to be resorbed lower down the column as would happen with a stable cationic species. This is an illustration of separation by elution analysis. Its most important application is in the separation of rare earths. When used on a laboratory scale in chemical analysis, this separation technique is known as ion-exchange chromatography. 

It would be easier to describe those classes of compounds not normally separated by RPLC than to catalogue the applications to which RPLC has been turned. Applications for reversed phase can be found in virtually every area of analysis and are reviewed regularly in the journal Analytical Chemistry. RPLC has not been in general use for the analysis of inorganic ions, which are readily separated by ion exchange chromatography polysaccharides, which tend to be too hydrophilic to separate by RPLC polynucleotides, which tend to adsorb irreversibly to the reversed phase packing and compounds which are so hydrophobic that reversed phase offers little selectivity. 

The chromatographic pumps and flow path used in IEC must be resistant to corrosion. For this reason, polymers such as poly(etheretherketone) (PEEK , ICI Americas Wilmington, DE) have entered into widespread usage in ion chromatography. Electrochemical detectors may also be subject to corrosion by certain ions. This chapter will review the chromatographic materials, detectors, and applications of ion exchange chromatography. For some classes of compounds, where reversed phase or normal phase alternatives may have been developed, alternative separation techniques will be presented. 

The applications of ion-exchange chromatography are exemplified by the selection shown in Table 4.18. Among the most notable are the separation of lanthanides and actinides using a citrate, lactate or EDTA eluting agent ... 

Many applications of porous materials such as for catalysis, adsorption, ion exchange, chromatography, solid phase synthesis, etc. rely on the intimate contact with a surface that supports the active sites. In order to obtain a large surface area, a large number of smaller pores should be incorporated into the polymer. The most substantial contributions to the overall surface area comes from mi-... 

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