Quantitative Analyses of Tocopherols in Autoxidized Methyl Linoleate

Abstract

An attempt to quantitate the tocopherol content in the autoxidized methyl linoleate was made by the iron (III) chloride-2, 2'-bipyridine method. But the quantitation was very difficult owing to the interference of hydroperoxides. This interference was also observed in t-butyl and cumene hydroperoxides, but not in di-t-butyl and dicumene peroxides. Such hydroperoxides as autoxidized methyl linoleate, t-butyl and cumene hydroperoxides catalyzed the Emmerie-Engel color reaction by itself as if it contained tocopherols. This result is contradictory to the earlier studies that the peroxides in fats inhibited the color development in the Emmerie-Engel procedure. Tocopherols in autoxidized methyl linoleate were quantitatively determined when hydroperoxides were removed by the potassium iodide treatment.