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Countercurrent approach to the enrichment of Δ9 c ,11 t ‐and Δ10 t ,12 c ‐18:2 isomers by urea complexation
Author(s) -
Ma David W. L.,
Field Catherine J.,
Clandinin M. T.
Publication year - 2002
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/s11746-002-0554-y
Subject(s) - urea , chemistry , structural isomer , countercurrent exchange , cis–trans isomerism , fraction (chemistry) , stereochemistry , chromatography , organic chemistry , biology , anatomy
CLA refers to a group of geometrical and positional isomers of linoleic acid. CLA has been shown to have potentially beneficial effects on cancer, atherosclerosis, and body metabolism in animals. Mixtures containing equal amounts of these isomers are commonly used in many research studies because of their greater availability and lower cost relative to pure isomers. This has hindered progress in elucidating the biological properties of specific isomers and their relevance in animal and human biology. A method was developed that offers a compromise between cost and utility to make available enriched mixtures of either the Δ9 c ,11 t ‐ or Δ10 t ,12 c ‐18:2 isomers for use in a wide range of experimental applications. A countercurrent approach was developed to separate the Δ9 c ,11 t ‐ and Δ10 t ,12 c ‐18:2 isomers from an equal mixture of these two isomers by urea complexation. After three successive rounds of complexation using an equal amount of CLA and urea, a fraction enriched in Δ9 c ,11 t ‐18:2 containing 42.5 and 17.4% of Δ9 c ,11 t ‐and Δ10 t ,12 c ‐18:2, respectively, was recovered. After a single round of complexation using 2.5 g urea/g CLA, a fraction enriched in Δ10 t ,12 c ‐18:2 was recovered containing 29.7 and 69.1% of Δ9 c ,11 t ‐ and Δ10 t ,12 c ‐18:2, respectively.