HYDROGENATION OF UNSATURATED FATTY ESTERS DURING ISOBUTANE CHEMICAL IONIZATION MASS-SPECTROMETRY

Hydrogenation of double bonds was observed to occur during the isobutane chemical ionization mass spectrometry of unsaturated fatty esters. Chemical ionization spectra of a series of methyl esters in the C16-C20 carbon range containing 0-4 double bonds showed a variety of ionization characteristics in the molecular ion cluster, including hydride abstraction, charge exchange, protonation and, for the unsaturated fatty acids hydrogenation of the double bond followed by protonation.