Automatic Injection Solid-Phase Microextraction--Chiral-Gas Chromatography--Mass Selective Detection Analyses of Essential Oils

A viable approach for the analysis of the enantiomeric distributions of volatile components in essential oils based on automatic injection solid-phase microextraction-chiral-gas chromatography-mass selective detection (AutoSPME-chiral-GC-MSD) is demonstrated. From a selection of polar and non-polar fibers of varying thickness, the relatively non-polar thin-film polydimethylsiloxane fiber is found to be the best fiber for the analysis. Fiber exposure to the headspace above sub-microliter quantities of the oils for approximately 6 s is all that is required to obtain both the required sensitivity and resolution to produce excellent reproducibilities (generally ≤ 5.0%). The findings using this approach are in good agreement with previous findings based on chiral-GC-flame ionization detection analysis of solutions of essential oils. These results clearly establish AutoSPME as a simple, rapid, accurate, and precise method of sample preparation for the qualitative and quantitative analysis of enantiomeric distributions within essential oils. This work will be expanded to include studies directed at determining the purity of additional essential oils as well as experiments directed at determining the production location of essential oils.