title: Quaternary ammonium substituted agarose as surface coating for capillary electrophoresis.
abstract: A novel positively charged polymer of quaternary ammonium substituted agarose (Q-agarose) has been synthesized and explored for use as a coating in capillary electrophoresis. The fast and simple coating procedure is based on a multi-site electrostatic interaction between the polycationic agarose polymer and the negatively charged fused-silica surface. By simply flushing fused-silica capillaries with hot polymer solution a positively charged, hydrophilic deactivation layer is achieved. The polymer surface provides an intermediate electroosmotic flow of reversed direction, over a range of pH 2-11, compared to unmodified fused-silica. The coating procedure was highly reproducible with an RSD of 4%, evaluated as the electroosmotic flow mobility for 30 capillaries prepared at 10 different occasions. The application of Q-agarose coated capillaries in separation science was investigated using a set of basic drugs and model proteins and peptides. Due to the intermediate electroosmotic flow generated, the resolution of basic drugs could be increased, compared to using bare fused-silica capillaries. Moreover, the coating enabled separation of proteins and peptides with efficiencies up to 300.000 plates m(-1).
authors.affiliation: Department of Analytical Chemistry, Uppsala University, P.O. Box 599, SE-751 24 Uppsala, Sweden.
authors.forename: Sara
authors.initials: S
authors.lastname: Ullsten
authors.forename: Lennart
authors.initials: L
authors.lastname: Söderberg
authors.forename: Staffan
authors.initials: S
authors.lastname: Folestad
authors.forename: Karin E
authors.initials: KE
authors.lastname: Markides
mesh_terms: D004587:Electrophoresis, Agar Gel / Q000379:methods; D019075:Electrophoresis, Capillary / Q000379:methods; D004364:Pharmaceutical Preparations / Q000032:analysis*; D012685:Sepharose / Q000031:analogs & derivatives*
chemical_list: D004364:Pharmaceutical Preparations; C039745:Sepharose 6MB; D012685:Sepharose