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 time window at 20% methanol, but its applicability is limited above 40% methanol. The SBDs modified with dodecyl groups provided high efficiency and much wider migration time windows than SDS micelle carriers at high methanol content, especially for hydrophobic compounds, based on their more hydrophobic properties and reduced electroosmotic mobility. Different selectivities were observed between octyl and dodecyl derivatives 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 of EKC separation with polymeric carriers by simply changing the organic solvent content to manipulate the solute retention as in reversed-phase liquid chromatography.