2.6. Analysis of fatty acid methyl esters by gas chromatography/mass spectrometry/flame ionisation detector (GC/MS and GC/FID)

GC-MS analysis was conducted on a Thermo Scientific Trace 1300 gas chromatography coupled to a flame ionisation detector and a Thermo Scientific Trace 1300 gas chromatography coupled to a Triple Quad mass spectrometer (Thermo Scientific, Burlington, Ontario, Canada) respectively. Conjugated methylated fatty acids were separated on a BPX70 high resolution column (10 m × 0.1 mm × 0.2 μm; SGE Analytical Science, Victoria, Australia) using helium as the carrier gas at a flow rate of 0.6 mL/min. One microliter (1 μL) of each FAME standard or sample was injected in the system in split mode (15:0) using a Tri-plus auto-sampler. The oven temperature program was as follows: the initial oven temperature 50 °C was held for 0.75 min, then programmed to increase at 4 °C/min to 155 °C, then increased again at 6.0 °C/min to 210 °C, and then increased again at 15 °C/min to finally reach 240 °C and held for 2 min. Identification of the conjugated fatty acids in meat as FAMEs was based on the comparison of their retention times and mass spectra with that of the Supelco™ 37 Component FAME Mix (1 mg/L), CLA and CLN methyl ester standards (Sigma Aldrich Oakville, Ontario, Canada). The amounts of fatty acid identified were calculated and expressed as mg/g meat [1].