Application of supercritical fluid chromatography and supercritical fluid extraction to the measurement of hydroperoxides in foods

Abstract

The applicability of supercritical fluid extraction (SFE) and supercritical fluid chromatography (SFC) for determining lipid peroxide levels in foods containing fats and oils was investigated. Lipid peroxide levels determined by SFC and SFE-SFC were compared with peroxide values (POVs) determined by conventional methods. The retention behaviour with respect to oil components in both the mobile phase of supercritical carbon dioxide modified with ethanol and the stationary phase of silica gel is similar to the retention behaviour in normal-phase high-performance liquid chromatography. SFC was found to be useful for measuring hydroperoxide compounds in small amounts of sample extracted from peanut oil with diethyl ether. The peak areas of peroxide compounds are in good agreement ( r = 0.9923) with POV determinations made by potentiometry. Coupled SFE-SFC provides useful qualitative and quantitative information, and can therefore serve as a simple high-speed method for extracting and separating hydroperoxide compounds. Compared with conventional methods, coupled SFE-SFC offers an advantage with regard to sample preparation by eliminating the need for preextraction when using solid samples.