W. Parr, P. Howard
May 3, 1972
Citations
0
Influential Citations
20
Citations
Journal
Journal of chromatography
Abstract
Abstract N-Trifluoroacetyl- l -norvalyl- l -norvaline 1 cyclohexyl ester has been synthesized in high yield and used as a stationary phase for the gas chromatographic enantiomeric separation of N-trifluoroacetyl- d,l -amino acid isopropyl esters. Separation factors and enthalpies of solution have shown a marked increase on solute-solvent interaction to occur for α-amino acids with a four-carbon group on the asymmetric carbon, while the same factors decrease as the substituent grows from one- to three-carbon. Mixtures of d,l -serine and d,l -leucine can now be resolved. Earlier phases have shown significant overlap between d isomers of leucine and serine as well as their l isomers, thereby precluding an accurate qualitative analysis of naturally occurring volatile amino acid derivatives. The phase has also been examined with respect to the separation of a mixture of common amino acids and their enantiomers and was found to be satisfactory.