Chiral selectors chromatographic analysis

Today, chromatographic modalities are used frequently for the analysis of chiral pollutants. The wide application of HPLC is due to the development of various chiral stationary phases and excellent reproducibility. However, HPLC suffers from certain drawbacks, as the chiral selectors are fixed on the stationary phase and, hence, no variation in the concentrations of the chiral selectors can be carried out. Moreover, a large amount of the costly solvent is consumed to establish the chiral resolution procedure. Additionally, the poor efficiency in HPLC is due to the profile of the laminar flow, mass transfer term, and possible additional interactions of enantiomers with the residual silanol groups of the stationary phase. GC also suffers from certain drawbacks as discussed in the Introduction. ... 

The appearance of capillary electrophoresis in the mid-1980s coincided with a period of important expansion of enantioseparation techniques," and soon it was applied to the analysis of enantiomeric mixtures of the most diverse character." As in HPLC, a chiral selector, with the ability to recognize stereoselectively the enantiomers, has to be incorporated into the separative system. This CS is either added to the background electrolyte as an additional solute, acts as a chiral surfactant forming chiral micelles, or incorporated as a constituent of the chromatographic support, which is filling the capillary. The difference in mobilities observed for enantiomers is the result of the differentiated association between each one of them and the CS and/or the difference in mobility of the transient diastereomeric adsorbates formed.""... 

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