Localization of unsaturation in fatty acids by identification of 2, 4-dinitrophenylhydrazones derived from ozonides by thin-layer chromatography.

The ozonides of unsaturated fatty acids may be reduced with 2,4-dinitrophenylhydrazine and the resulting aldehydes reacted with an excess of this same reagent to give the 2,4-dinitrophenylhydrazones of the aldehyde and aldoester fragments. The 2,4DNP of the aliphatic aldehydes can be separated by several thin-layer chromatography systems and are identifiable on the basis of their behavior in these systems. The methods described can be utilized for both qualitative identification as to the location of the double bond and for quantitative measurements of various positional isomers in some instances. All of the reactions may be performed on the plate for qualitative application, and the method can be applied to fatty acids in various forms.