Chemical ionization (NO) spectra of n-alkenoic acids and their esters

It is shown that the position of one double bond in long-chain unsaturated fatty acids and their esters can be determined by chemical ionization (NO) mass spectra. Homoconjugated dienoic acids (as linoleic acid) do not give a characteristic framentation pattern, in contrast to those which contain three or more homoconjugated double bonds.