Field ionization mass spectrometry of long chain fatty methyl esters

Abstract

AbstractMass spectrometry is particularly useful for identifying lipid materials. One primary factor in the interpretation of mass spectra is the recording of the molecular ion peak giving the molecular weight of the compound. Regrettably many compounds, including hydroxy compounds, do not give significant molecular ion peaks; consequently their identification is difficult. A mass spectrometer equipped with a field ionization source produces a greatly different mass spectrum consisting almost entirely of the molecular ion peak. This new source was used to measure the mass spectra of methyl esters of saturated, unsaturated and hydroxy fatty acids. Saturated esters gave the molecular ion peak almost exclusively; unsaturated esters yielded molecular plus metastable ion peaks; whereas the hydroxy esters had molecular, M‐18, meaastable and fragment ion peaks.