DETERMINATION OF HIGHER FATTY ACIDS IN OILS BY HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY WITH ELECTROCHEMICAL DETECTION

摘要

A system of high-performance liquid chromatography with electrochemical detection was developed for the separation and determination of higher fatty acids. An octadecylsilica (ODS) column was used as the stationary phase and an ethanol-acetonitrile (10:90) mixture as the mobile phase. The eluate was mixed with a quinone solution which was composed of 6 mM 2-methyl-1,4-naphthoquinone and 76 mM LiClO4 in ethanol-acetonitrile (10:90) through a mixing coil. Peak height for higher fatty acids measured at -415 mV vs. saturated calomel electrode (SCE) was linear against the amount of acid between 20 and 1200 pmol. Free fatty acids in various oil samples were determined by this method, which was found not only sensitive and reproducible but also a simple means for separating and determining free fatty acids in oils.