Chromatography enantiomer separation

The first cellulose enantioseparation was of a racemic amino acid by paper chromatography [8]. Early cellulose TLC smdies were aimed at repeating paper chromatography enantiomer separations more quickly and with better resolution. Cellulose TLC has mostly been used for amino acids, their derivatives, and peptides and the following are examples of successful enantioseparations. Aromatic amino acids were separated on polyester-backed 20 x 20 cm plates by elution with methanolic aqueous 0.1 M HCl (A) or ethanol/pyridine/water (1 1 1) (B). Typical respective R values were 0.75/0.81 for l- and o-tyrosine in mobile phase A and 0.37/0.46 for L- and D-5-methyl tryptophan in B [9,10]. 

W. A. Kirnig, The Practice of Enantiomer Separation by Capillay Gas Chromatography, Hbthig Vedag, Heidelberg, Germany, 1987. 

A. Mosandl, U. Hener, U. Hagenauer-Hener and A. Kuster mann, Stereoisomeric flavor compounds. 33. Multidimensional gas chromatography dkect enantiomer separation of -y-lactones from fr uits, foods and beverages , 7. Agric. Food Chem. 38 767-771 (1990). 

B. Sellergren, Enantiomer separation using tailor-made phases prepared by molecular imprinting in A practical approach to chiral separations by liquid chromatography, G. Subramanian, VCH, Weinheim (1994) Chapter 4. 

Despite the difficulties caused by the rapidly expanding literature, the use of chiral stationary phases (CSPs) as the method of choice for analysis or preparation of enantiomers is today well established and has become almost routine. It results from the development of chiral chromatographic methods that more than 1000 chiral stationary phases exemplified by several thousands of enantiomer separations have been described for high-performance liquid chromatography (HPLC). 

Pais L. S., Loureiro J. M., Rodrigues A. E. (1998a) Modeling Strategies for Enantiomers Separation by SMB Chromatography, AIChEJ 44 561-569. 

Figure 8.43 Separation of enantiomers using complexation chromatography. A, Separation of alkyloxiranes on a 42 m x 0.2S mm I.O. open tubular column coated with 0.06 M Mn(II) bis-3-(pentafluoro-propionyl)-IR-camphorate in OV-ioi at 40 C. B, Separation of D,L-amino acids by reversed-phase liquid chromatography using a mobile phase containing 0.005 M L-histidine methyl ester and 0.0025 M copper sulfate in an ammonium acetate buffer at pH 5.5. A stepwise gradient using increasing amounts of acetonitrile was used for this separation.

Volume inefficient chiral chromatography required to deliver a single enantiomer Separation at final API necessitated processing excess material through the synthesis to give the desired amount... 

Rojkovicova, T., Hrobonova, K., Lehotay, J., Cizmarik, J. (2003a). Coupled column chromatography for separation and determination of enantiomers of phenylcarbamic acid derivatives in serum. Pharmazie 58, 108-110. 

Dondi M, Flieger M, Olsovska J, Polcaro CM, Sinibaldi M (1999) High-performance liquid chromatography study of the enantiomer separation of chrysanthemic acid and its stationary phase. J Chromatogr A 859 133-142... 

It is possible to use chromatography to separate chiral compounds (enantiomers see Section 11.6). This technique uses a stationary phase... 

Affinity liquid chromatography and chiral separations (enantiomer separations) require similar analyte properties. The solutes may have interactions through hydrogen-bonding, ligand formation, or Coulombic forces with the surface of stationary phase materials or the sites of additives however, the selectivity is controlled by the steric effects of the structures of the analyte molecules and the recognition molecules (chiral selectors). 

Pihlainen, K. and Kostiainen, R., Effect of the eluent on enantiomer separation of controlled drugs by liquid chromatography-ultraviolet absorbance detection-electrospray ionisation tandem mass spectrometry using vancomycin and native fi-cyclodextrin chiral stationary phases, J. Chromatogr. A, 1033, 91, 2004. 

Chiral ligand-exchange chromatography (CLEC) ° separates enantiomers by the formation of diastereomeric metal complexes. In a first instance the technique was mainly used for the separation of amino acids. Impressive results of the first separations gave rise to intensive investigation in the field and numerous publications appeared in the literature, which have been reviewed. 

A lot of published data on the separation of enantiomers of flavors and fragrances by GC is reviewed by Chirbase/Flavor database. Table 1. summarizes the enantiomer separation of oxygenated monoterpenes on chiral stationary phases of cyclodextrin derivatives by high resolution gas chromatography. 

Table 1. Enantiomer Separation of Oxygenated Monoterpenes on Chiral Stationary Phases of Cyclodextrin Derivatives by High Resolution Gas Chromatography...

Schurig V. Enantiomer separation by complexation gas chromatography — Applications in chiral analysis of pheromones and flavours, in Schreier P (ed.), Bioflavour 87, Walter de Gruyter, Berlin, Germany, pp. 35—54, 1988. 

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