Carbonyls in Oxidizing Fat. IX. Aldehydes Isolated from Autoxidized Methyl Arachidonate

SUMMARY The monocarhonyl compounds developed by oxidation of methyl arachidonate under mild conditions were measured by three methods of isolation. Aldehydes from scission of hydro‐peroxides of the pentadiene system furthest removed from the carboxyl group accounted for 80% of the total, and the same ones are characteristic of oxidized linoleate. The C, alkanal was the major aldehyde and C, alkanal, a compound not readily accountable for by conventional mechanisms of autoxidation, was second in quantity. The mild quantitatively equal Girard T and Schwartz methods broke down scnne precursors, but in a qualitatively different manner. The Pool and Klose alumina chromatographic method decomposed precursors, but not to the extent that has been observed in autoxidized lard. Two unsaturated aldehydes isolated by this method may be alk‐2,4,6‐trienals.