RESORCARENES AS PSEUDOSTATIONARY PHASES WITH SELECTIVITY FOR ELECTROKINETIC CHROMATOGRAPHY

Resorcarenes, macrocyclic molecules built up by four alkylidene-bridge d resorcinol units, have been studied as new pseudostationary phases i n order to develop a different mode of pseudophase and to attain a dis tinct selectivity for electrokinetic chromatography (EKC), This novel pseudostationary phase has several advantages over traditionally used surfactants in micellar electrokinetic chromatography, First, the stab le structure of the cyclic tetramer permits the use of high contents o f organic modifiers, i.e., > 60% (v/v) acetonitrile, to adjust optimum capacity factors, Second, high electrophoretic mobility of the resorc arenes is based on four negative charges delocalized and stabilized ov er hydrogen bonds, This supplies a broad elution range, which is a mai n parameter for resolution of separated peaks. Furthermore, these reso rcarenes possess unique selectivity for hydrophobic compounds, The ord er of peak elution with a test mixture involving 12 polycyclic aromati c hydrocarbons (PAHs) is almost identical with that from reverse-phase highperformance liquid chromatography, The first two terms exclude th e contribution of microheterogeneity that decreases the efficiency of EKC when common surfactants are used as pseudophases, The selectivitie s of resorcarenes with methyl, pentyl, undecyl, and p-chlorophenyl gro ups at the bridging carbons in separation of PAHs are discussed as a f unction of these residues.