Estimation of monocarbonyl compounds in rancid foods

A convenient method for the determination of monocarbonyl compounds in rancid foods is described. The quantitative procedure is based on the formation of the 2,4-dinitrophenylhydrazones of monocarbonyl compounds in benzene solution, the removal of excess hydrazine reagent and the hydrazones of dicarbonyl compounds with alumina, and the colorimetric determination of the remaining hydrazones of monocarbonyl compounds in alkaline solution. Applicability to aldehydes varying in molecular size and degree of unsaturation has been demonstrated. The method may be used on the crude benzene extracts of rancid foods. Illustrative data are presented.