Chromatographic techniques enantiomeric separation

Gomera, B., Gonzalez, M.J. (2003). Enantiomeric separation of chiral PCBs in eggs of predatory birds from Donana National Park (Spain) by using multidimensional gas chromatographic techniques. Organohalogen Compounds 62, 273-276. 

Liquid Chromatography. The development of rapid, simple liquid chromatographic methods for determining the enantiomeric purity of chiral compounds is probably one of the most important developments in the study of asymmetric synthesis in the last 10 years. Several books have been published providing thorough evaluations of various enantiomeric separation techniques and their practical applications.46... 

A wide variety of CSPs have been synthesizsed and several of them are commercially available. Their use is nowadays the most favored chromatographic technique used to separate enantiomeric drugs by means of HPLC. In the case of CSPs, the enantiomers that form a stronger association with the chiral selector will be more strongly retained. Interaction... 

Chelate complexes with two ethylenediamine rings in a cis configuration lack a plane of symmetry and thus have the potential to be separated into enantiomeric (A, A) (12) forms. Inert cis-bis(en) complexes of Co111,247 Crmn or Rh111248 can be resolved by the method of racemic modification 249 or using chromatographic techniques,35 but labile systems, such as Ni(en)2+, which occasionally crystallize in one chiral form,220 rapidly racemize in solution. 

The derivatization of analytes is very important in several branches of analytical chemistry. It expands the fields of application of various spectroscopic techniques (ultraviolet-visible (UV-vis), fluorimetry, nuclear magnetic resonance (NMR), and mass spectroscopies), and in several cases increases also the selectivity and sensitivity of these techniques. Derivatization is also an inevitable tool in all chromatographic and electrophoretic techniques. In gas chromatography (GC), the main importance of derivatization is the improvement of the volatility/thermal stability of the analytes, and in all of the discussed separation techniques it has the potential of increasing the selectivity of the separation (including enantiomeric separations) and the sensitivity of the detection. 

Amino acids and their derivatives] resolution of amino acids and dieir derivatives on impregnated layers, 406-408 resolution of enantiomeric mixtures of amino acids and their derivatives, 411-419 separation of amino acid derivatives, 398-406 DABITC derivatives of amino acids, 403-406 dansyl amino acids, 402 dinitrophenyl-amino acids, 406 PTH amino acids, 399-402 separation of amino acids, 389-398 chromatographic techniques, 393-395 preparation of test materials, 389-392 TLC system for amino acids, 395-398 Aminoglycosides, 457-461 Amino-modified precoated silica layers, 114,117-119... 

In order to characterize the chiral nature of a drug substance, and to then track its optical purity on stability, a method which can resolve the subtle chiral differences between the main chiral form, and its optical isomer is required. The most robust way to measure chiral purity is to separate the two enantiomers by means of a chiral chromatographic technique. Once the species are separated, they can easily be quantitated by UV detection. In order to achieve a separation of two enantiomers, they must interact in some way with a second enantiomeric species. There are two general method of how to accomplish this chromatographic separation. ... 

This first chapter will present the world of chiral separation by listing and defining the terms used in the field, giving a brief historical view followed by a general description of enantiomeric interactions and mechanisms involved in enantiosepa-rations. Chromatographic techniques are greatly emphasized due to the background of the author. 

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