Submitted to: Journal of Chromatography
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/18/1997
Publication Date: N/A
Interpretive Summary: Conjugated linoleic acid (CLA) has been associated with the reduction of chemically-induced cancers in mice and rats and the suppression of atherosclerosis in rats. A method to separate the various isomers was developed using commercially available materials. This allowed us to quickly analyze deuterium-labelled CLA we synthesized in our laboratory for use in tissue studies and to study its metabolism in humans and animals. Development of this methodology allows us to isolate small quantities of these biologically-important materials.
Technical Abstract: Utilizing two commercially available Ag-HPLC columns connected in series, a solvent system of 1.0 mL/ min 0.35% acetonitrile in hexane and UV detection @206 nm, we applied Ag-HPLC to the separation of the biologically important conjugated linoleic acid methyl esters. [Elution order (10 micro g sample size): 9-trans,11-trans-18:2; 9-cis,11-trans-18:2]. A more complex mixture eof cis and trans oleic, linoleic and conjugated linoleic FAME could also b fractionated within 25 min. [Elution order (10 micro g sample size): 9 trans-18:1; 9-trans,11-trans-18:2; 9-trans,12-trans-18:2; 9-trans,11-cis 18:2; 9-cis,11-trans-18:2; 9-cis-18:1; 9-trans,12-cis-18:2; 9-cis,12-trans 18:2; 9-cis,12-cis-18:2. The elution orders observed with Ag-HPLC are often the reverse of those obtained via gas chromatography (30m SP2380 capillary column; Elution order: 9-trans-18:1; 9-cis-18:1; 9-trans,12 trans-18:2; 9 cis,12-trans-18:2; 9-trans,12-cis-18:2; 9-cis,12-cis-18:2;9 cis,11-trans 18:2; 9-trans,11-cis-18:2; 9-trans,11-trans-18:2).