Abstract: In the present study,the separatation effects of different elaidic acid,trans-vaccenic acid,and linolelaidic acid mainly contained in food under different gas chromatography(GC) conditions. It was found experimentally that the optimal GC condition are as follows:HP-88 capillary column(60m×0.25mm,0.2 μ m),column temperature 180 ℃; sampler temperature:250 ℃,detector temperature:250 ℃,pure N2 as carrier gas,pure N2 pressure 100kPa,plue N2 flow rate:16 ml/min,hydrogen pressure 100 kPa,hydrogen flow rate 28ml/min,air pressure 160kPa,air flow rate:200 ml/min,split injection mode with the split ratio of 30:1 and tail-blows rate 18 ml/min. Elaidic acid(C18:1,t9)、linolelaidic acid(C18:2,t9 t12)and trans-vaccenic acid(C18:1,t11) can be separated completely within 30 min under these operation conditions. And the linear scopes are between 0.05mg/ml and 0.4mg/ml(r>0.998). The detection limits of the three trans fatty acid are 6.84×10-15 g/s,8.28×10-15 g/s,and 6.57×10-15 g/s,respectively. The recovery rate of the method from esterification to GC detection is between 85.29% and 86.41% with the relative standard deviation is between 1.47%and 8.50%.

Key words: trans-fatty acid, gas chromatography(GC)