POLYMER-SUPPORTED PSEUDO-STATIONARY PHASE FOR ELECTROKINETIC CHROMATOGRAPHY - ELECTROKINETIC CHROMATOGRAPHY IN A FULL RANGE OF METHANOL-WATER MIXTURES WITH ALKYLATED STARBURST DENDRIMERS

Alkylated polyamidoamine starburst dendrimers (PAMAM-SBDs) are used as high-performance carriers in electrokinetic chromatography (EKC) in a full range of water-methanol (up to 90%) mixtures. The sodium dodecyl sulfate-micellar EKC (SDS-MEKC) system showed a greater migration tim e window at 20% methanol, but its applicability is limited above 40% m ethanol. The SBDs modified with dodecyl groups provided high efficienc y and much wider migration time windows than SDS micelle carriers at h igh methanol content, especially for hydrophobic compounds, based on t heir more hydrophobic properties and reduced electroosmotic mobility. Different selectivities were observed between octyl and dodecyl deriva tives of SBDs, the latter showing some similarity with the SDS micelle carrier. The results, showing a nearly linear relation between log k' and methanol content, indicate the possibility for the optimization o f EKC separation with polymeric carriers by simply changing the organi c solvent content to manipulate the solute retention as in reversed-ph ase liquid chromatography.