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Determination of the specific positions of cis and trans double bonds in polyenes
Author(s) -
Privett O. S.,
Nickell E. C.
Publication year - 1966
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/bf02532998
Subject(s) - double bond , chemistry , ozonolysis , ozonide , cis–trans isomerism , polyunsaturated fatty acid , double layer (biology) , organic chemistry , chromatography , fatty acid , layer (electronics)
A method is described for the determination of the positions and geometric configurations of double bonds in polyunsaturated fatty acids. The procedure consists of three steps: Partial reduction of the double bonds with hydrazine under conditions which give high yields of monoenes. Isolation of the cis ‐ and the trans ‐monoene fractions by thin‐layer chromatography (TLC) directly or in the form of their ozonide derivatives. In the former technique, selective argentation is employed, in the latter, silicic acid adsorption. Determination of the structure of the monoenes via reductive ozonolysis.The position of the double bonds is determined from the structures of the monoenes. Since the cis ‐monoenes are separated from the trans ‐monoenes the geometric configuration of each double bond is determined. The method also provides a direct determination of the spacings of the internal double bonds and it may be employed for the determination of the structures of mixtures of fatty acids in conjunction with direct ozonolysis procedures. The various ramifications of the method are demonstrated on pure fatty acids and model mixtures thereof.