| The fatty acids in animal fats and vegetable oils could be effectively detected by comprehensive two-dimensional gas chromatography coupled with mass spectrometry(GC×GC-MS). After methylation of fatty acids with methanol solution of TMAH (volumn ratio 1∶?50), the second column, temperature programming, mass scanning range, cold blow flow and modulation period were optimized. The results showed that under the conditions of column set of DB-5MS（30 m×0.25 mm×0.25 μm）as the first column, BP20（2.5 m×0.1 mm×0.1 μm）as the second column, modulation period 5 s, cold blow flow 3 L/min, mass scanning range (m/z) 71-385,temperature programming from 40?℃（2 min） to 190?℃ at 30?℃/min, from 190?℃ to 280?℃ (15 min)at 2?℃/min, the fatty acid compositions of animal fats and vegetable oils were separated effectively and determined accurately. Compared with GC-MS, GC×GC-MS method was more sensitive and had better separation effect, which could be the effective method to discriminate different animal fats and vegetable oils. |
