Lawrence J F, Charbonneau C F
Food Research Division, Health Protection Branch, Ottawa, Ontario, Canada.
J Chromatogr. 1988 Jul 8;445(1):189-97. doi: 10.1016/s0021-9673(01)84520-9.
Free fatty acids (C8-C18) are separated by reversed-phase liquid chromatography and detected using a simple post-column dynamic extraction system in which the acids are extracted as ion pairs with chloroform from the aqueous acetonitrile (gradient: 79-99% acetonitrile) mobile phase after the post-column addition of aqueous Methylene Blue solution. The chloroform phase containing the ion pairs is monitored with an absorbance detector at 651 nm. The detection limits ranged from 26 to 83 ng, depending upon the acid, with coefficients of variation of 1.2-14%. Application of the method to butter and margarine samples permitted detection of free fatty acids down to 35 ppm and in orange juice, down to 0.5 ppm using only an organic solvent extraction without further sample clean-up for isolation of the fatty acids.
游离脂肪酸（C8 - C18）通过反相液相色谱法进行分离，并使用一种简单的柱后动态萃取系统进行检测。在此系统中，柱后加入亚甲蓝水溶液后，游离脂肪酸以离子对的形式从乙腈水溶液（梯度：79 - 99%乙腈）流动相中被氯仿萃取出来。含有离子对的氯仿相通过吸光检测器在651 nm波长下进行监测。检测限在26至83 ng之间，具体取决于脂肪酸种类，变异系数为1.2 - 14%。该方法应用于黄油和人造黄油样品时，能够检测到低至35 ppm的游离脂肪酸；应用于橙汁时，仅通过有机溶剂萃取，无需进一步的样品净化以分离脂肪酸，就能检测到低至0.5 ppm的游离脂肪酸。
