GC-MS法检测婴儿配方奶粉甘油三酯中Sn-2位棕榈酸
Determination of palmitic acid in the Sn-2 position in infant formulas by GC- MS
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摘要: 研究建立一种高效、准确测定婴儿配方奶粉甘油三酯中Sn-2位棕榈酸含量的方法。采用国际标准化委员会（ISO）14156的方法提取脂肪,利用猪胰脂酶专一水解甘油三酯Sn-1,3位脂肪酸,通过氨基固相萃取柱法分离水解产物中单甘油酯,甲酯化后用气相色谱-质谱联用仪（GC-MS）检测Sn-2位棕榈酸。结果表明用氨基固相萃取柱法取代传统薄层层析法分离单甘油酯不仅操作简单,分离效果好,而且回收率高,测定结果准确,GC-MS法检测3种婴儿配方奶粉中Sn-2位棕榈酸占总棕榈酸的含量分别为40.5%、40.3%和40.8%,添加回收率范围为91.7%98.5%,RSD为1.56%,重现性良好,完全适用于婴儿配方奶粉甘油三酯Sn-2位棕榈酸含量的检测。Abstract: To establish a highly efficient and accurate determination of Sn-2 palmitic acid in triglycerides of infant formulas.Lipids of milk powder were extracted by the method of ISO14156. The Sn-1,3 fatty acids in the triglycerides were specially hydrolyzed by pancreatic lipase.The 2-monoglyceride was separated and prepared by solid phase extraction( SPE),and analyzed by gas chromatography-mass spectrometry( GC-MS). Results showed that the content of palmitic acid esterified at the Sn-2 position was 40.5%,40.3%,40.8%. The average spike recoveries for palmitic acid were 91.7% ~ 98.5%,and the relative standard deviation was 1.56%. The developed method was proved to be simple,precise,accurate and reliable,thereby being suitable for the determination of Sn-2 palmitic acid in infant formulas.
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