Resolution of Optical Isomers by Gas Liquid Partition Chromatography

Abstract

Enantiomers can be analysed by conversion into diastereoisomers and gas chromatography on a capillary column of 150 ft. and 0.01 in. I.D. 2-n-Alkanols containing from 4 to 19 carbon atoms were resolved via the α-alkanoyloxypropionates on squalane, polypropylene glycol and FS-1265. Alanine, valin, leucine, isoleucine, allo-isoleucine, proline, phenylalanine, hydroxyproline, methionine, lysine, aspartic and glutamic acid were resolved through the N-TFA esters of 2-n-butanol and/or 2-n-octanol on polypropylene glycol, butanediol succinate and trifluoropropylmethylpolysiloxane. Peak assignment was made through synthesis with optically active reagents for almost all compounds. The DL (or LD) diastereoisomer was found to have the higher retention time in all cases. Satisfactory agreement was obtained for quantitative analysis by polarimetric and gas chromatographic measurements. Some of the diastereoisomers could be separated on packed columns.