5977a single quadrupole mass spectrometer

Total phenolic content was determined using the Folin–Ciocalteu method [12 (link)]. The sample was extracted using 80% MeOH, and the absorbance was measured at 720 nm. The policosanol content was analyzed using an Agilent 7890A gas chromatography system coupled with a 5977A single quadrupole mass spectrometer (Agilent Technologies, Palo Alto, CA, USA) [4 (link)].

All samples were analyzed using an Agilent 7890B gas chromatography (GC) instrument equipped with an Agilent 7693 autosampler and injector. A capillary column, J&W HP-88 (60 m × 0.25 mm i.d.) with a film thickness of 0.2 µm was connected to the GC and Agilent 5977A single quadrupole mass spectrometer (MS). Ultra-pure helium was used as the carrier gas at a flow rate of 1.2 mL/min. The samples were analyzed using the following oven program: starting from 60 °C held for 1 min, then programmed at 10 °C/min to 145 °C, then 1 °C/min to 190 °C, and finally at 5 °C/min to 240 °C. The inlet was operated in split mode at a temperature of 260 °C. The split ratio was 10:1 with 2 µL of each sample being injected. The transfer line from the GC to the MS was held at 260 °C, while the source and quadrupole were maintained at 230 °C and 150 °C, respectively, throughout the experiment.

WV, derived from pine pyrolysis, was procured from Neoliquid Advanced Biofuels and Biochemicals S.L. (Guadalajara, Spain). WV was characterized using different methods. The pH was determined using a 692 pH/Ion Meter (Metrohm) equipped with a Solitrode glass electrode with a temperature probe Pt1000 (Metrohm). The water content was calculated by Karl Fischer titration using a Metrohm oven sample processor. Gas chromatography was performed using the conditions described in previous studies (Aguirre et al., 2020 (link); Martín et al., 2017 (link)). An Agilent 7,890 A gas chromatograph coupled with a 5,977 A single quadrupole mass spectrometer (Agilent Technologies) and a Phenomenex ZB‐624 column (30 m; 0.25 mm i.d.; 0.25 μm film thickness, 6% cyanopropylphenyl/94% dimethylpolysiloxane) was used for this purpose. The quantification was performed using the internal standard method, by constructing a calibration curve for each of the following compounds: acetic acid (40–515 ppm), hydroxyacetone (40–515 ppm), hidroxyacetaldehyde (50–960 ppm), furfural (10–110 ppm), and levoglucosan (10–200 ppm). A constant concentration of internal standards (IS) 1‐octanol (830 ppm) and cresol (115 ppm) was added at each point on the calibration lines. Quantification was performed based on the areas determined by extracting the quantifying ion from each compound, in both standards and samples.