7890b 5977a msd

The essential oil samples were diluted in a 1:10 ratio with dichloromethane and subjected to analysis using gas chromatography coupled with mass spectrometry (GC–MS) on an Agilent 7890B-5977A MSD instrument. The analysis utilized an HP-5MS UI 5% (30 m × 0.25 mm × 0.25 µm) capillary column with specific temperature parameters. Initially, the oven temperature was set at 60 °C for 3 min. Subsequently, the temperature was gradually increased at a rate of 5 °C/min until it reached 300 °C, where it was maintained for 10 min. Finally, the temperature was further increased to 310 °C at a rate of 10 °C/min for an additional 10 min. The carrier gas employed was helium, flowing at a linear speed of 1 mL/min. For injection, the essential oil samples were introduced in split mode (20:1), with an injection volume of 1 µL at an injector temperature of 300 °C. The transfer line, ionization source, and quadrupole were maintained at temperatures of 280 °C, 230 °C, and 150 °C, respectively. Mass spectrometry data were acquired within a scan range of 30 to 550 m/z, with a solvent delay of 3 min. The identification of compounds was accomplished by comparing their mass spectra with those available in the NIST 11.0 libraries, in addition to evaluating their retention indices (RI) obtained using a standard homologous series (C₇–C₄₀) [63 ].