摘要：
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-5 MS (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 °C (2 min) to 190 °C at 30 °C/min,from 190 °C to 280 °C (15 min) at 2 °C/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.%为建立动植物油的全二维气相色谱-质谱分析方法,选用四甲基氢氧化铵(25％)的无水甲醇(体积比1∶50)对样品进行甲酯化衍生,对二维色谱柱、程序升温、质量扫描范围、冷吹流量、调制周期进行优化.结果表明:在调制周期5 s,冷吹流量3 L/min,DB-5MS(30 m×0.25 mm×0.25 μm)为一维柱,BP20(2.5 m×0.1 mm×0.1 μm)为二维柱,质量扫描范围(m/z)71 ～385,程序升温为初始温度40°C,保持2 min,以30°C/min升温至190°C,再以2°C/min升温至280c°C,保持15 min的条件下,动植物油中的脂肪酸组成得到了有效分离和准确检测,比气相色谱-质谱法灵敏度、分离效果均提高.为动植物油的进一步鉴别提供新的分析方法.
