SEPARATION OF ISOMERIC COMPOUNDS BY REVERSED-PHASE HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY USING AG+ COMPLEXATION - APPLICATION TO CIS-TRANS FATTY-ACID METHYL-ESTERS AND RETINOIC ACID PHOTOISOMERS

The improvement of the chromatographic efficiency using Ag+ complexing reversed-phase liquid chromatography for the analysis of geometric isomers was studied. The influence of the nature and concentration of silver salts on pi-complex formation was investigated with two types of sample, fatty acid methyl esters and trans-retinoic acid photoisomers. First, the separations of cis-trans-linoleic acids and cis-trans-oleic acids were confirmed. Second, the pi-complexation was shown to occur with more complex chemical structures such as trans-retinoic acid and its photoisomers. The chromatographic separation of seven geometric isomers of trans-retinoic acid was then carried out with good efficiency in half the time required in previous work.