MASS-SPECTRAL CHARACTERIZATION OF PICOLINYL AND METHYL-ESTER DERIVATIVES OF ISOMERIC THIA FATTY-ACIDS

Picolinyl and methyl ester derivatives of all the isomeric thialaurates and thiastearates, together with some dithiastearates, have been characterized by gas chromatography/mass spectrometry. The picolinyl ester derivatives give simple electron impact mass spectra in which ions formed by cleavage at the sulphur atom and containing the sulphur atom are especially distinctive. The methyl ester derivatives have much more complex mass spectra, again dominated by ions formed by cleavage at the sulphur atoms, although all possible fragments are seen. With both derivatives, the spectra are readily interpretable in terms of the positions of the sulphur atoms. The position of the sulphur atom can also have a marked effect on the abundance of the McLafferty rearrangement ion.