Mass spectrometry of derivatives of isomeric allenic fatty acids

The electron impact mass spectra have been obtained for isomeric C14 and C18 allenic fatty acids in the form of the methyl and picolinyl ester derivatives. When the allene moiety was in positions 3 to 9, the mass spectra of the methyl esters gave spectra with diagnostic ions that appeared to be formed by beta cleavage on the distal side of the molecule; otherwise hydrocarbon ions were dominant. With the picolinyl ester derivatives, distinctive fragmentations beta to the allene moiety on each side were observed for each isomer.