Separation of Triacylglycerols from Edible Oil Using a Liquid Chromatography-Mass Spectrometry System with a Porous Graphitic Carbon Column and a Toluene-Isopropanol Gradient Mobile Phase

This study presented a rapid and practical method of separating triacylglycerol (TAG) from edible oil using high-performance liquid chromatography (LC) coupled with atmospheric-pressure chemical ionization (APCI)/mass spectrometry (MS) system with a porous graphitic carbon column (150 mm x 2.1 mm, 5 mu m) and a toluene-isopropanol- formic acid mobile phase. After investigating the experimental conditions, the gradient toluene-isopropanol mobile phase containing 0.1% formic acid was changed from 50:50 to 80:20 in 30 min; the column temperature was set to 35 degrees C, and APCI/MS was used in the positive-ion acquisition mode. The TAG retention displayed a special order and was summarized to fit as follows: S-ECN (special equivalent carbon number) = 2CN (carbon number) - 3dB (double bond number) - 5uFA (unsaturated fatty-acid number). Then, the LC-MS method was applied to separate TAG in 6 vegetable oils, resulting in the recognition of 27 TAG in corn oil, 21 TAGs in olive oil, 22 TAG in sunflower seed oil, 28 TAG in soybean oil, 25 TAG in sesame oil, and 31 TAG in peanut oil. The TAG separation through the LC-MS method was rapid, reproducible, and durable.