6890n gc ms system

For qualitative analysis of the EO chemical composition, an Agilent 6890N GC‐MS system coupled with a 5973N single‐quadrupole detector and a 7863 autosampler (Agilent, Wilmington, DE, USA) was employed. A capillary HP‐5MS column was used (5% phenylmethylpolysiloxane, 30 m length, 0.25 mm internal diameter, 0.1 μm film thickness; Agilent). The temperature of the oven was held at 60 °C for 5 min, then ramped up at 4 °C min⁻¹ until 220 °C and finally ramped at 11 °C min⁻¹ to 280 °C. The flow rate of the carrier gas He (99.5%) was set at 1 mL min⁻¹. Once diluted in n‐hexane (LC‐MS) 1:100, the EOs were injected in split mode with an electron energy of 70 eV. The major EO compounds were identified by co‐injection of analytical standards, whereas the other constituents were found by comparing retention indices (RIs) and mass spectra to those reported in the literature.¹⁰, ¹¹, ¹²

The chemical composition of hemp EOs was analyzed through an Agilent 6890N GC-MS system coupled to a 5973N single quadrupole detector mass spectrometer. Separation was provided by a HP-5MS capillary column (5% phenylmethylpolysiloxane, 30 mL × 0.25 mm i.d., 0.1 µm f.t., Agilent, Santa Clara, CA, USA). The temperature program was as follows: 60 °C for 5 min, then 4 °C min⁻¹ up to 220 °C, finally 11 °C min⁻¹ to 280 °C, maintained for 15 min, for a total run time of 65 min. The temperature of the injector and detector was 280 °C. Helium (He) was the carrier gas, with a flow rate of 1 mL min⁻¹ and a 1:50 split ratio. The chromatograms were acquired in full scan in the range 29.0–400.0 uma, using electron-impact (EI, 70 eV) mode. Dilution 1:100 of essential oils in n-hexane was injected (2 µL) into the GC-MS system. The MSD ChemStation (Agilent, Version G1701DA D.01.00) and the NIST Mass Spectral Search Program were employed for the data analysis. The identification of the principal compounds was achieved by the correspondence of retention indices and mass spectra to those of ADAMS, NIST 17, FFNSC2, and WILEY 275 libraries. Furthermore, the analytical standards available in the laboratory (Sigma-Aldrich, Milan, Italy) were used for further confirmation. The relative peak area percentages were obtained by area normalization without using correction factors [49 (link)].

A total of 6 µL of the ajowan EOs and 594 µL of analytical-grade n-hexane (Sigma-Aldrich, Milan, Italy) were injected in split-mode (split ratio 1:50) into an Agilent 6890 N GC-MS system, endowed with a 5973 N single quadrupole detector and an autosampler 7863. As a stationary phase, a 5% phenyl-methylpolysiloxane coated capillary column (Agilent HP-5MS, 30 m length, 0.25 mm internal diameter, 0.1 μm film thickness) was used. The temperature program was set as follows: 5 min isothermal at 60 °C, then ramp at 4 °C/min to 22 °C and, finally, ramp at 11 °C/min until 280 °C, maintained for 15 min. The flow rate of the carrier gas (helium 99.5%) was 1 mL/min and both the injector and detector were at 280 °C. The mass spectra were achieved between 29.0 uma and 400.0 uma in a full scan through the electron impact mode (EI, 70 eV). The major chemical constituents of the T. ammi EOs, namely p-cymene, γ-terpinene, and thymol, as well as carvacrol, were identified using analytical standards (Sigma-Aldrich, Milan, Italy), whereas the other components were identified by combining the temperature-programmed retention indices (RIs) and the mass spectra (MS), as detailed in our previous study [59 (link)].