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A method for the determination of linoleic acid and conjugated dienoic acids in materials containing eleostearic acids
Author(s) -
O'Connor R. T.,
Heinzelman D. C.,
Pack F. C.,
Planck R. W.
Publication year - 1953
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf02640295
Subject(s) - conjugated system , chemistry , organic chemistry , conjugated linoleic acid , composition (language) , absorption (acoustics) , linoleic acid , fatty acid , polymer , linguistics , philosophy , physics , acoustics
Summary A procedure has been described which extends the scope of the spectrophotometric method for polyun‐saturated acids to the determination of linoleic and conjugated acids in the presence of large quantities of conjugated trienoic acids. Basis for the proposed method rests on equations which are offered to correct the “end” or “back‐ground” absorption of the highly absorbing triene conjugated acids at 233 mμ, the position of maximum absorption of conjugated dienoic acids and alkali isomerized linoleic acids. The method is limited to samples which do not contain nonconjugated trienoic acids (linolenic acids). The method has been tested by the analysis of several mixtures of cottonseed and dehydrated castor oils of known composition, to which varying amounts of alpha, beta, and mixtures of alpha‐ and beta‐eleostearic acids have been added. These samples have been used to demonstrate the application of the proposed method for the determination of dienoic conjugated acids, alpha‐eleostearic acid, beta‐eleostearic acid linoleic acid, oleic acid, and total saturated fatty acids. Comparisons of the results obtained with similar values, calculated from the known composition of the mixtures, prove that the proposed method gives reasonable results. Standard deviations between determined and calculated results vary from 0.36 for diene conjugated acids to 1.40 for oleic acid. The method has been applied to the analysis of foreign and domestic tung oils.