The use of the polarograph to distinguish between the peroxide structures in oxidized fats

A polarographic method for the determination of peroxides has been applied to fats and related esters. The data presented show that at least three different peroxide structures are present in early stages of oxidation and persist during extensive autoxidation. The peroxides of lard, methyl oleate, and methyl linoleate cannot be distinguished by the polarographic method used in this investigation. Autoxidation of lard at 100°C. is shown to give reduction curves which are much different from those obtained when lard is autoxidized at 45°C. Preliminary work has indicated that the chromatographic technique of Dugan et al. does not separate the peroxide structures which are determined polarographically.