ISSN:
1052-9306
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Methane-, isobutane- and vinyl methyl ether-chemical ionization mass spectra were unsatisfactory for discrimination between cyclopropanoid fatty acid methyl esters and their monoene isomers using packed column gas chromatography mass spectrometry. A methodology was developed whereby these isomers could be distinguished by using a mixture of methane and vinyl methyl ether as the chemical ionization reactant gas. The spectra of the monoene fatty acid methyl esters displayed a series of vinyl methyl ether adduct ions, which were less than one-tenth as abundant in the spectra of the isomeric cyclopropanoid compounds. A greater degree of discrimination was achieved using isobutane/vinyl methyl ether as a mixed reagent gas, when unsaturated fatty acid methyl esters yielded a vinyl methyl ether adduct ion which was essentially absent (reduced to approx. 2%) in the spectrum of the isomeric cyclopropanoids. These adduct ions could be used to clearly define the occurrence of the monoenoic compounds in the presence of isomeric cyclopropanoids. Examples of the use of this method, in conjunction with catalytic hydrogenation, for the identification of cyclopropanoid fatty acid methyl esters in several Thiobacillus spp. and of monounsaturated fatty acid methyl esters in the fungus, Trametes lilacinogilva, are presented.
Additional Material:
4 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/bms.1200071005
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