Ring location in cyclopropane fatty acid esters by a mass spectrometric method

Ring location in cyclopropane fatty acid esters is accomplished simply and unequivocally with submilligram samples. The technique involves reductive ring opening with platinum catalyst and hydrogen in glacial acetic acid, to give a mixture of branched-chain and straight-chain acid esters. The sample is analyzed with a combination gas chrmatograph-mass spectrometer. Examination of the spectra obtained from the mixture of branched-chain acid esters permits assignment of the position of the methyl groups, and hence of the ring in the parent compound.