Db fatwax ui column

The fatty acid composition of oils was analyzed using gas chromatography–mass spectrometry (GC-MS, TQ-8040, Shimadzu, Kyoto, Japan). Fatty acid mixture esters (FAME) were separated on a DB-FATWAX UI column (30 m × 0.25 mm × 0.25 μm; Agilent Technologies). The injector operated in the split mode with a 20:1 ratio and at a temperature of 260 °C. The mass detector was set to positive ion electron impact mode at 70 eV with the ion source at a temperature of 300 °C over a scan range of 50–700 m/z. Helium was used as a carrier gas at a constant flow rate of 0.5 mL/min. Calibration curves were constructed using FAME Mix C8-C24 standards.

The oil samples in the model system were extracted with petroleum ether and placed in a centrifuge tube. Then 2 mL of n-heptane and 0.1 mL of 2 M potassium hydroxide-methanol solution were added respectively. After mixing with a vortex mixer for 30 s, centrifuge at 4,800 rpm for 5 min, and take 1 mL of supernatant through a 0.22 μm filter for injection.
Analysis of linoleic acid was carried out using Agilent 8860 gas chromatography (GC) equipped with a flame ionization detector (FID) and a DB-FATWAX UI column (0.25 mm × 3 m, 0.25 μm; Agilent Technologies Inc., Santa Clara, CA, USA). The oven temperature program was as follows: 60°C held for 3 min, then increased to 170°C at 35 °C/min, held for 5 min, followed by heating up to 180°C at 5°C/min, held for 15 min, and finally increased at a rate of 5°C/min to 200°C. The helium flow rate was maintained constant at a flow rate of 1 mL/min and shunt ratio was 10:1.

Seed oil content in Brassica napus cv. Westar (Canola) was analyzed from 10 seeds of individual plants that were dried over silica beads (Thermo Fisher Scientific, Waltham, MA, USA). Seeds were weighed and combined in a 10 cm × 1 cm glass tube with 1 mL of toluene containing 80 µg tripentadecanoin (15:0) as an internal standard and 0.0005% (w/v) butylated hydroxy toluene (BHT). Samples were then ground using a tissue homogenizer (Polytron PT 2500E, Kinematica, Bohemia, NY, USA) and seed material was rinsed from the homogenizer with an additional 2 mL methanol that was combined with the sample. Next, 1 mL of 15% (v/v) conc. sulfuric acid in MeOH was added and tubes were sealed using PTFE lined caps. Samples were incubated at 85–90 °C for 2 h with samples being inverted every half hour. After samples cooled, 2 mL of hexane and 1.5 mL 0.88% (w/v) potassium chloride (KCl) were added, samples were vortexed, and phase separation was achieved by centrifuging samples at 3000× g for 3 min. Fatty acid methyl esters (FAME) extracted in the upper hexane layer were analyzed using Agilent model 7890 GC with an attached flame ionization detector and a DB FATWAX UI column (30 m × 0.25 µm; Agilent, Santa Clara, CA, USA) following the method described in [49 (link)].