*3.3. Gas Chromatography-Mass Spectrometry (GC-MS) Analysis*

The GC-MS analyses were carried out according to the in-house method and the procedure previously reported by Kuiate et al. [61] with some adjustments. The instrument consisted of an Agilent GC-7820A fitted with an HP-5MS fused silica column (30 m × 0.25 mm i.d. × 0.25 μm film thickness) and coupled with an Agilent 5977E mass selective compartment (Agilent Technologies, Inc., Santa Clara, CA, USA). The oven temperature was programmed at 50 ◦C for 5 min, 50–220 ◦C at a rate of 2 ◦C.min−<sup>1</sup> then 220 ◦C temperature hold for 5 min for the first ramp. For the second ramp, the temperature was set to 300 ◦C at a rate of 25 ◦C.min−1. Helium was used as a carrier gas at 1 mL.min−<sup>1</sup> flowrate and pressure of 7.6522 psi. Sample injection of 1 μL of 1% (*v*/*v*) solution diluted in n-hexane was splitless and operated at 250 ◦C. A reference standard of homologous n-paraffin series of C8-C20 (Sigma-Aldrich®, St. Louis, MO, USA, Cat no. 04070) was prepared and co-injected under identical experimental conditions as the samples for the determination of retention indices (RIs). The MS spectra were obtained on electron impact at 70 eV scanning from 30.0 to 650 *m*/*z*.

The identification of the constituents was achieved by computerized matching (MassHunter software, Agilent Technologies, Inc., Santa Clara, CA, USA) of each mass spectrum generated with authentic samples (if available) and with those stored in the instrument's built-in mass spectral libraries (National Institute of Standards and Technologies, NIST), comparing of the experimental RIs [62] with those of the NIST online data collection [25] and literature [23,24]. The relative amounts of individual constituents were calculated automatically based on the total ion count detected by the GC-MS and expressed as percentage composition.
