气相色谱技术测定棉籽及其饼（粕）中环丙烯脂肪酸含量Determination of cyclopropene fatty acids in cottonseed and its cake (meal) by gas chromatography

Abstract

为了解决棉籽及其饼（粕）中环丙烯脂肪酸分析测定的技术难题，通过比较脂肪酸衍生化方法、优化气相色谱条件建立了气相色谱技术（GC）测定棉籽及其饼（粕）中环丙烯脂肪酸（锦葵酸和苹婆酸）含量的方法。结果表明：碱式甲酯化对环丙烯脂肪酸的衍生化效果最佳；优化的GC条件为DB-1ht毛细管柱，氮气流速0.6 mL/min，升温程序为从100 ℃以2 ℃/min的速度上升到220 ℃。在此基础上，通过建立苹婆酸与锦葵酸回归方程（R2 ≥ 0.997）测得棉籽、棉籽饼和棉籽粕中的锦葵酸含量分别为2.62、0.68 mg/g和0.09 mg/g，苹婆酸含量分别为1.02、0.27 mg/g和0.04 mg/g。方法的重复性和回收率良好，为棉籽及其饼（粕）中环丙烯脂肪酸的分析检测提供了技术依据和指导。 In order to solve the technical problem of analysis and determination of cyclopropene fatty acids in cottonseed and its cake (meal), gas chromatography (GC) for determination of cyclopropylene fatty acids (malvalic acid and sterculic acid) in cottonseed and its cake (meal) was developed by comparing the methods of fatty acids derivatization and optimizing GC conditions. The results showed that the alkali methyl esterification exhibited a highest efficiency on the derivatization of cyclopropene fatty acids. The optimized GC method required an increasing from 100 ℃ to 220 ℃ at a rate of 2.0 ℃/min at a N2 flow rate of 0.6 mL/min using a DB-1ht capillary column. Thus, the regression equations (R2 ≥ 0.997) of sterculic acid and malvalic acid were established. The contents of malvalic acid in cottonseed, cottonseed cake and cottonseed meal were 2.62, 0.68 mg/g and 0.09 mg/g, and the contents of sterculic acid in cottonseed, cottonseed cake and cottonseed meal were 1.02, 0.27 mg/g and 0.04 mg/g, respectively. The method has good repeatability and recovery, and this finding provides technical basis and guidance for the analysis and determination of cyclopropene fatty acids in cottonseed as well as cottonseed cake and meal.

Keywords

• 棉籽；环丙烯脂肪酸；气相色谱法；甲酯化；苹婆酸；锦葵酸
• cottonseed; cyclopropene fatty acids; gas chromatography; methyl esterification; sterculic acid; malvalic acid