Online coupling of enantioselective capillary gas chromatography with proton nuclear magnetic resonance spectroscopy.
The hyphenation of enantioselective capillary gas chromatography and mass spectrometry is not always sufficient to distinguish between structural isomers, thus requiring peak identification by NMR spectroscopy. Here the first online coupling of enantioselective capillary gas chromatography with proton nuclear resonance spectroscopy is described for the unfunctionalized chiral alkane 2,4-dimethylhexane resolved on octakis(6-O-methyl-2,3-di-O-pentyl)-gamma-cyclodextrin at 60 degrees C. NMR allows constitutional and configurational isomers (diastereomers and enantiomers) to be distinguished. Enantiomers display identical spectra at different retention times, which enable an indirect identification of these unfunctionalized alkanes. The presented method is still at an early development stage, and will require instrumental optimization in the future.
Kühnle
Maximilian
M
Institute of Organic Chemistry, University of Tübingen, Tübingen D-72076, Germany.
Kreidler
Diana
D
Holtin
Karsten
K
Czesla
Harri
H
Schuler
Paul
P
Schurig
Volker
V
Albert
Klaus
K