建立同时测定配方奶粉中脂肪酸和反式脂肪酸的气相色谱分析方法。样品中的脂肪酸和反式脂肪酸经乙酰氯-甲醇甲酯化处理后，用气相色谱仪测定，采用HP-88色谱柱分离定性，以十一碳酸甘油三酯为内标进行定量。结果表明：顺-反异构体脂肪酸分离效果较好，脂肪酸和反式脂肪酸的回收率在97.2%~104.6%之间，相对标准偏差小于3.5%，检出限为5 μg/g。

A internal standard method to determine cis- and trans- fatty acids in formula powders by gas chromatography was developed. Samples were methylesterized with acetyl chloride-MeOH，and analyzed by GC on a HP-88 column with FID as detector and triundecanoin as the internal standard. The results showed that cis- and trans- fatty acids in formula powders were well separated by this method. The recoveries, relative standard deviation and the detection limit of the GC method were 97.2%~104.6%, less than 3.5% and 5 μg/g, respectively.