Ingalls S T, Xu Y, Hoppel C L
Department of Veterans Affairs Medical Center, Cleveland, OH 44106, USA.
J Chromatogr B Biomed Appl. 1995 Apr 7;666(1):1-12. doi: 10.1016/0378-4347(94)00555-j.
Non-esterified fatty acids (NEFA) and triglycerides were isolated from human plasma by column chromatography on silica gel. Eight principal fatty acids of each of these lipid classes were determined by gas chromatography of their methyl ester derivatives and quantified relative to multipoint standard curves. Within-day relative standard deviations for plasma non-esterified fatty acid and triglyceride fatty acid determinations were 2.4 and 3.2%, respectively. Day-to-day relative standard deviations for plasma non-esterified fatty acid and triglyceride fatty acid determinations were 1.4 and 1.1%, respectively. The total plasma concentration and the relative proportions of the eight non-esterified fatty acids determined by this method were significantly different from results obtained according to two generally accepted methods for direct plasma non-esterified fatty acid determination without a specific isolation step. These comparisons suggested that considerable fatty acid ester lipid hydrolysis occurred during these direct determination procedures, and that this hydrolysis resulted in 3-fold overestimation of plasma NEFA content by those methods. Measured levels of arachidonic acid are substantially overestimated by these direct determination methods in which non-esterified fatty acids are not isolated before derivatization.
通过硅胶柱色谱法从人血浆中分离出非酯化脂肪酸（NEFA）和甘油三酯。通过对其甲酯衍生物进行气相色谱分析，测定了这些脂质类别中每种的八种主要脂肪酸，并相对于多点标准曲线进行定量。血浆非酯化脂肪酸和甘油三酯脂肪酸测定的日内相对标准偏差分别为2.4%和3.2%。血浆非酯化脂肪酸和甘油三酯脂肪酸测定的日间相对标准偏差分别为1.4%和1.1%。用该方法测定的血浆总浓度和八种非酯化脂肪酸的相对比例与根据两种普遍接受的直接血浆非酯化脂肪酸测定方法（无特定分离步骤）获得的结果显著不同。这些比较表明，在这些直接测定过程中发生了大量脂肪酸酯脂质水解，并且这种水解导致那些方法将血浆NEFA含量高估了3倍。在这些直接测定方法中，在衍生化之前未分离非酯化脂肪酸，花生四烯酸的测量水平被大幅高估。
