Comprehensive Two-Dimensional Gas Chromatography with Fast Enantioseparation

The development of fast chiral analysis for use in comprehensive two-dimensional gas chromatography in which a short second dimension enantioselective capillary column provides a route to precise measurement of chiral ratios of enantiomers is described. Retention times as short as 8 s are reported for (±)-limonene, with adequate enantioseparation maintained (Rs ∼ 1.0) on a 1-m cyclodextrin derivative-coated capillary column. Sufficiently fast elution on the second column was achieved by using GC/MS in which the subambient pressure (vacuum outlet) conditions promote increased diffusion coefficients and higher component volatility; a 4-fold reduction of second-dimension retention time was observed, as compared with ambient pressure outlet conditions. The enantiomeric distribution of several monoterpene compounds in bergamot essential oil is reported as a demonstration of the method. Total analysis time of the target components was ∼8.5 min.