Retention behavior of N-TFA-O-alkyl derivatives of selected amino acid enantiomers separated on modified cyclodextrins by HRGC

The retention behavior of N-trifluoroacetyl-O-alkyl esters of selected amino acids with various types of alkyls in ester group was studied by capillary gas chromatography with modified cyclodextrin stationary phases. A model set of six different esters of five amino acids was analyzed on two columns coated with permethyl-beta-cyclodextrin bonded to polysiloxane elastomer (ChirasilDex), and heptakis (6-O-tert-butyldimethylsilyl-2,3-di-O-acetyl)-beta-cyclodextrin dissolved in OV 1701 in a 1:1 ratio. It was found that the variation of enantiomeric separation with temperature and elution sequence of enantiomers depends on the nature of alkyl groups bonded both to asymmetric carbon atom and in ester group. A temperature dependent inversion of elusion sequence was observed for N-TFA-O-n-butyl valine derivative on ChirasilDex column. (C) 1996 John Wiley & Sons, Inc.