Classification of chromatographic methods

Basis of Classification of Chromatographic Methods Classification is based on the phenomenon involving the process of either partition or adsorption. 

Figure 1.2 Classification of chromatographic methods according to the operating method. (Reprinted from Ref. 22 with permission.)...

The nature of the stationary and the mobile phases, together with the mode of the transport through the column, is the basis for the classification of chromatographic methods. 

Figure 1.3 Classification of chromatographic methods according to development procedure, for components A, B, C and eluant E.

A more fundamental classification of chromatographic methods is one based on the types of mobile and stationary phases and the kinds of equilibria involved in the transfer of solutes between phases. Table 26-1... 

However, the most frequently employed classification of chromatographic methods, which is independent of the separation mechanism, is based on the state of the mobile and stationary phases (Table 1.1.). 

Saturated solutions of some reagents (T) 829 Schoniger oxygen flask see Oxygen flask Schwarzenbach classification 53 Screened indicators 268 Sebacic acid 469 Secondary pH standards 831 Selective ion meters 567 Selectivity coefficient, 559 in EDTA titrations, 312 in fluorimetry, 733 of analytical methods, 12 Selenium, D. of as element, (g) 465 Semi-log graph paper 572 Sensitivity (fl) 834, (fu) 732 Separation coefficient 163, 196 Separations by chromatographic methods, 13, 208. 233, 249... 

Figure 4.10 Classification of liquid chromatographic methods depending on the polarity of the stationary and mobile phases. After Schaffer el at. [537]. Reproduced by permission of Metrohm AG, Herisau, Switzerland...

E Ruckenstein, V Lesins. Classification of liquid chromatographic methods based on the interaction forces The niche of potential barrier chromatography. In A Mizrahi, ed. Advances in Biotechnological Processes, Vol 8 Downstream Processes Equipment and Techniques. New York Alan R. Liss, 1988, pp 241-314. 

In addition to the classification of liquid chromatographic enantioseparation methods by technical description, these methods could further be classified according to the chemical structure of the diverse CSPs. The chiral selector moiety varies from large molecules, based on natural or synthetic polymers in which the chirality may be based on chiral subunits (monomers) or intrinsically on the total structure (e.g., helicity or chiral cavity), to low molecular weight molecules which are irreversibly and/or covalently bound to a rigid hard matrix, most often silica gel. 

In the rest of the chapter, various chromatographic methods will be discussed. You should recognize that no single chromatographic technique relies solely on adsorption or partition effects. Therefore, little emphasis will be placed on a classification of the techniques instead, theoretical and practical aspects will be discussed. 

There are two ways to classify liquid chromatographic methods. The first and more common classification is based on the mechanism of retention, and from this the chromatographic modes discussed in Chapter 2 are derived. For example, the normal-phase mode can be performed by taking advantage of either the adsorption mechanism or the partition mechanism. The gel-filtration mode is performed using the mechanism of size exclusion. The second classification discussed below is based on the separation principle and is found mostly in the literature published before the 1990s. 

Liquid chromatographic methods may be classified according to either the mechanism by which analytes are retained on the column or the mechanism by which they are removed from it. The mechanism of retention classification is the most popular scheme, and five major retention mechanisms have been identified ... 

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