气相色谱法定量分析共轭亚油酸异构体

Analysis of Conjugated Linoleic Acid Isomers by Gas Chromatography

共轭亚油酸(CLA)是亚油酸的位置和几何异构体。其中9c,11t-CLA和10t,12c-CLA是目前发现生理活性比较强的两种共轭结构。作者使用氢氧化钾甲醇溶液对油脂中的共轭亚油酸甘三酯进行水解和甲酯化,利用毛细管气相色谱进行分离后外标法定量。作者得到共轭亚油酸9c,11t-CLA回收率在97.66%～103.51%之间,10t,12c-CLA回收率在96.12%～102.48%之间,检出限2.4 mg/kg,定量限8 mg/kg。

Conjugated linoleic acids(CLA) are the positional and geometric isomers of linoleic acid,among them,9 c,11t-CLA and 10 t,12 c-CLA exhibited the stronger biological activity.In this study,a method was developed for the quantitative determination of 9 c,11t-CLA and 10 t,12 c-CLA by capillary gas chromatography.The sample of CLA oil was methylated with KOH in methanol.The calculation of results was carried out with external standards.The recovery of 9c,11tCLA and,10 t,12 c-CLA was between 97.66% ～103.51%,96.12% ～102.48%,respectively.The detection and quantitation limits were separately 2.4 mg/kg and 8 mg/kg.