气相色谱法测定食品中反式脂肪酸的研究进展

气相色谱法(GC)是测定食品中反式脂肪酸(TFAs)的常用方法,该方法灵敏度高、准确度好。然而,由于来源于反刍动物的天然TFAs(n-TFAs)与部分氢化油的工业TFAs(IP-TFAs)的组成不同,以及不同食品中不饱和脂肪酸的组成差异,无法利用一种固定操作程序完全分离并准确分析各类食品中的TFAs组成。本文通过分析食品中TFAs的来源与组成,系统综述了GC法分析TFAs的原理和操作步骤,包括样品前处理方法、甲酯化衍生方法、Ag+预分离法,色谱条件(如色谱柱、柱长、柱温、进样口温度和检测器温度等)的选择和优化,以及常见的定性、定量分析方法。同时介绍了目前国内外标准方法的适用范围和特点,以便帮助分析人员依据实际样品以及所在实验室条件选择适合的分析方法。

Research progress on analysis of trans fatty acids in food by gas chromato-graphy

Gas chromatography (GC) is sensitive and accurate method which is widely used for the determination of trans fatty acids (TFAs) in variety of foods. However, it is generally impossible to separate and determine multiple TFAs in different foods by a fixed GC step, because the composition of TFAs from ruminant fats, partially hydrogenated oils are different, and unsaturated fatty acids in various foods are complex which seriously interfere the separation of TFAs. In the present paper, the principles and operation steps in the determination of trans fatty acids by GC were systematically introduced, based on the analysis of sources and composition of TFAs in foods. The sample pretreated methods, methyl ester derivatization methods, silver (Ag+) pre-separation, chromatographic conditions (including column type and length, column temperature, inlet and detector temperature), qualitative and quantitative methods have been detailed reviewed. To help analysts to choose optimal methods on the basis of samples, analytical requirements and laboratory conditions, the scopes and characteristics of the current standard methods were also presented.