Agilent 7890b 7000b gc ms

Essential oil from P. cablin leaves was extracted by ultrasonic extraction (Yan et al., 2021 (link)). The extracts were dried over anhydrous sodium sulfate, and the resulting essential oils were stored at −10 °C prior to GC-MS analysis. Three individual replicates of each sample collected under the same conditions were analyzed.
GC-MS analysis was carried out on an Agilent 7890B-7000B GC-MS (Agilent Technologies, Santa Clara, CA, USA) and performed according to a previously described method (Yan et al., 2021 (link)). The PA content was quantified by an external standard curve, and the relative content of PO was also calculated based on the PA standard curve. The quantification of PA and PO is presented as the means of at least three replicates ± standard error.

The GC-MS analysis was performed with three replicates of C. oleifera samples using an Agilent 7890B-7000B GC-MS (Agilent Technologies, USA) instrument equipped with an HP-5MS silica capillary column (0.25 mm × 30 m × 0.25 μm). The injector and interface were maintained at 250°C. The thermal program was as follows: heating from 60 to 270°C at 6°C per minute and holding at 270°C for 2 min. The splitless injection mode was used, and the injected volume was 1.0 μl. Helium with a purity of 99.995% was used as the carrier gas at a flow rate of 1.0 ml/min. The split ratio was 10:1.
The MS conditions were as follows: ion source, electron ionization (EI); ion source temperature, 230°C; EI mode, 70 eV; mass range, 50–450 mz⁻¹; electron multiplier voltage, 2.0 kV; and full-scan mode with a solvent delay of 4 min. The components were identified based on their unique retention indices (RIs) in accordance to the National Institute of Standards and Technology (NIST) database. Then, the absolute content of fatty acids were calculated based on the corresponding regression equations [40 ].