To determine the fatty oil compositions of biodiesel samples (1 μL) can be injected into gas chromatography equipped with a flame ionization detector and a BPX70 capillary column of 30 m × 0.25 μm × 0.32 mm. An initial temperature of 140°C was held for 2 min, which was then increased at 8°C per minute to 165°C, 3°C per minute to 192°C, and finally 8°C per minute to 220°C. The column was held at the final temperature for another 5 min. The oven, injector, and the detector ports were set at 140°C, 240°C, and 260°C, respectively. The carrier gas was helium with column flow rate at 1.10 mL/min at a 50:1 split ratio. Table 17.4 shows an example of GC operating condition to determine fatty oil compositions [1,50].