GC-MS Analysis of Essential Oils

For determination of the chemical composition of basil leaves, leaves of peppermint, and clove buds EOs, gas chromatography–mass spectrometry (GC-MS) analysis was conducted using GC-2010 Shimadzu capillary gas chromatography directly coupled to the mass spectrometer system (GC-MS–model QP 2010; (Shimadzu, Kyoto, Japan)) DB-c18 column under the following conditions: The injector temperature was 250 C. Oven temperature program: 30 °C for 2.0 min, then ramp to 250 °C at a rate of 2.0 degrees Celsius per minute for 5.0 min. The MS source temperature was 200 °C, electron energy was 70 eV, the carrier gas was helium at a flow rate of 1.4 mL/min, and 1 µL of each diluted sample in n-hexane (1:1, v/v) was injected. EI spectra were scanned from 43.00 to 600 m/z to identify peaks through NIST mass data-search libraries and the highest REV and similarity indicators’ hits. The sample components were identified by comparing their relative indices and mass spectra with the computer controlling the GC-MS system [37 (link),38 (link)].
Table 3 shows the VOCs in star anise essential oil. The main compound in the essential oil is (E)-Anethole* accounted for 89.24% of oil, followed by lower contents. Volatile organic compounds exhibited powerful potential against parasites [39 (link)].