A micellar electrokinetic chromatography (MEKC) method has been developed f
or the direct resolution of divinyl ether type of hydrophobic fatty acid is
omers. The fatty acid isomers resolved include colneleic acid ICL), colnele
nic acid (CLn), 14(Z)-etheroleic acid (14(Z)-EL), 14(Z)-etherolenic acid (1
4(Z)-Eln), 11(Z)-etheroleic acid (11(Z)-EL), 11(Z)-etherolenic acid (11(Z)-
Eln), etheroleic acid (EL) and etherolenic acid (Eln). These fatty acid iso
mers differ in number, position and spatial arrangement of the double bonds
and the position of the ether oxygen. A central composite design was emplo
yed for the optimization of the key variables of the separation, namely the
concentrations of sodium dodecyl sulfate (SDS) and organic modifiers. The
use of micelles combined with an organic modifier in the background electro
lyte made it possible to dissolve and separate relatively hydrophobic fatty
acid isomers, and to achieve high separation efficiency. Using heptakis-(2
,3-dimethyl-6-sulfato)-beta -cyclodextrin (HDMS-beta -CD) as a buffer addit
ive, complete separation of the examined eight divinyl ethers was achieved.
Separation efficiencies up to 5 x 10(5) theoretical plates/m were achieved
under optimized conditions. Direct UV was applied for detection of the fat
ty acids. The results were compared with those obtained from high-performan
ce liquid chromatography (HPLC) separation.