Application of comprehensive two-dimensional gas chromatography (GC x GC) to the qualitative analysis of essential oils

This paper investigates the separation of moderately complex samples by comprehensive two-dimensional gas chromatography (GC x GC). The analysis of peppermint (Mentha piperita) and spearmint (Mentha spicata) essential oil components, including acetates, alcohols, furans, ketones, sesquiterpenes, and terpenes, was achieved by one-dimensional gas chromatography with quadrupole mass spectrometry detection (GC/MSD) and GC x GC with flame ionization detection. Peppermint essential oil was found to contain 89 identifiable peaks by GC x GC compared to 30 peaks in the GC/MSD chromatogram. Likewise, 68 peaks were found in the GC x GC chromatogram of spearmint (compared to 28 in GC/MSD). Plots of the first dimension versus second dimension retention times provided a fingerprint of the two essential oils, which revealed 52 similar compounds between the two essential oils as opposed to 18 matches by 1D GC.