Chromatographic properties separation factor

Zn > Cd > Ca > Mg > Th. From the separation factor values, it is clear that these resins show wide differences in their affinities for different ions and this property has been used for the chromatographic separation of these metal ions. Due to the higher affinity of these phosphorus-containing resins for divalent and mutivalent ions compared to univalent ions, these resins can be used for the isolation of traces of divalent ions, Cu, Pb, and Zn, from solutions containing a high concentration of monovalent ions. 

G. Tsitsishvili Our studies of zeolite chromatographic properties indicated that the retention volumes, separation factors, and other characteristics are strongly dependent on cation nature, degree of exchange, and temperature. We have observed the inversion of the sequence of elution by temperature alteration. 

Fig.l Effect of isotherm shape on certain chromatographic properties, (a) Three different shapes of sorption isotherms encountered in chromatography (b) peak shapes resulting from these isotherms (c) dependence of the retention factor on the amount of solute injected. (From Karger, B. L., L. R. Snyder, and C. Horvath, An Introduction to Separation Science, John Wiley Sons, New York, 1973.)... 

For two peaks to be resolved chromatographically, the capacity ratios, Kj and K2, must be different. For analytical purposes, two interdependent chromatographic properties must be considered the chromatographic separability factor, a, and the resolution, Rs. The chromatographic separability factor is defined as... 

The main purpose of a chromatographic study is the separation of compounds with closely similar properties. The factor separation Rjj of the chromatographic zones of two compounds / and i is described by the equation... 

The individual properties studied were the selectivities, separation factors, valley-to-peak ratios and overlapped fractions. The two first criteria only consider the position of the chromatographic peaks, and the latter two their position and shape. The three latter functions may vary from 0 to 1. The combined function of resolution, r, is maximized to obtain the optimum mobile phase, and its proximity to unity indicates the quality of the separation. Since the product of all observed resolutions is used, coelution will effectively cause the criterion to drop to zero. Extremely long chromatograms with a number of unnecessarily large resolution values will also be represented by low criterion values. 

The first observation of the enantioselective properties of an albumin was made in 1958 (28) when it was discovered that the affinity for L-tryptophan exceeded that of the D-enantiomer by a factor of approximately 100. This led to more studies in 1973 of the separation of DL-tryptophan [54-12-6] C22H22N2O2, on BSA immobilized to Sepharose (29). After extensive investigation of the chromatographic behavior of numerous racemic compounds under different mobile-phase conditions, a BSA-SILICA hplc column (Resolvosil-R-BSA, Macherey-Nagel GmvH, Duren, Germany) was... 

Solvent selectivity is seen as the factor that distinguishes individual solvents that have solvent strengths suitable for separation. In reality, separations result from the competition between the mobile and stationary phases for solutes based on the differences of all intermolecular interactions with the solute in both phases. Solvents can be organized on selectivity scales that are useful for initial solvent selection, but in a chromatographic separation the properties of the stationary phase must be taken into consideration. Methods that attempt to model chromatographic separation need to consider simultaneously mobile and stationary phase properties [38]. 

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