Abstract: A gas chromatography method with hydrogen flame ionization detection was proposed to analyze the fatty acid composition of infant milk powder by temperature-programmed heating. Samples were hydrolyzed with hydrochloric acid and extracted with ether-ethanol-petroleum ether (1:1:1, V/V) for lipids. The extracted lipids were reacted with potassium hydroxide in methanol prior to being analyzed by gas chromatography. The method showed good figures of merit. The average recoveries for mixed standards of seven fatty acids in infant formulas for three different age groups spiked at three levels were 86.4%– 103.9%, and the precision of the method was 0.91%–3.82% (RSD, n=6). In addition, this method exhibited a high sensitivity and a limit of detection of 0.1 mg/100 g. Compared with the national standard method, it required more simple and rapid sample pretreatment and easier operation while providing excellent reproducibility, thus being suitable for primary laboratories.

Key words: DING Hong-mei， ZHANG Xia，ZHU Yun，CHEN Gang

摘要： 将婴幼儿奶粉经盐酸水解后,利用乙醚-乙醇-石油醚(1∶1∶1,V/V)提取脂肪,然后经氢氧化钾-甲醇溶液甲基化反应后,用附带氢火焰检测器的气相色谱仪,按照程序升温测定出奶粉中脂肪酸组成.各项检测指标理想,该检测方法相对标准偏差(RSD)为0.91％～3.82％,回收率为86.4％～103.9％,灵敏度高,检测限为0.1mg/100g,与国家标准相比,样品处理方法简单快捷,易于操作,方法重现性良好.

关键词: 婴幼儿奶粉；脂肪酸组成；检测方法