摘要
采用毛细管气相色谱的方法，以十五碳烷酸为内标，对紫苏子油中的五种游离脂肪酸：棕榈酸（Ｃ（１６：０））、硬脂酸（Ｃ（１８：０））、油酸（Ｃ（１８：１））、亚油酸（Ｃ（１８：２））、亚麻酸（Ｃ（１８：３））进行分析，研究紫苏子油中五种游离脂肪酸在储藏期间的变化。此分析方法无需进行甲基化，直接分析游离脂肪酸的变化。研究中对每种脂肪酸都作了方法学研究，脂肪酸的线性范围在 １４７～９２２ ｐｐｍ之内，ｒ~2值≤０．９９９７。精密度≤２．４３％（ｎ＝５）。最后用此法测定了不同储藏期间的样品，结果显示随储藏时间的延长，游离脂肪酸的总量增加，但各脂肪酸的变化情况不同。
This paper reports a split-mode capillary gas chromatographic method that developed for the analysis of five free fatty acids in Perilla seed oil. The five free fatty acid are palmitic acid (C_(16:0)), stearic acid (C_(18:0)), oleic acid(C_(18:1)), linoleic acid (C_(18:2))and linolenic acid (C_(18:3)). The method does not need methlated, fatty acids can be directly injected with pentadecanoic acid (C_(15:0)) as internal standard. For each fatty acid, the method is validated for selectivity,linearity, , precision and reptoducibility. All fatty acids are completely resolved. Linear response from 147 to 922ppm, r^2-value at least 0.9997, the precision is not more than 2.62% (within day). Finally, we study on the variation of free fatty acid in perilla seed oil by this method.
