Extraction of Essential Oils and Terpene Volatiles from Plants and Identification by GC-MS-Based Techniques.

The extraction of plant essential oils (EOs) and analysis by gas chromatography coupled to mass spectrometry (GC-MS) are standard methods when studying aromatic plants and the chemical composition of EOs. Here, two simple methods for the extraction of EO compounds from leaves of Thymus vulgaris are described. Organic solvent extraction and solid-phase microextraction (SPME), respectively, are used and the results of the GC-MS analyses are compared. We explain how analyte peaks can be identified and discuss possible rearrangement reactions that can occur during the extraction process or analysis.