title: Evaluation of migration behaviour of therapeutic peptide hormones in capillary electrophoresis using polybrene-coated capillaries.
abstract: Modelling electrophoretic mobility as a function of pH can be simultaneously used for determination of ionization constants and for rapid selection of the optimum pH for separation of mixtures of the modelled compounds. In this work, equations describing the effect of pH on electrophoretic behaviour were used to investigate migration of a series of polyprotic amphoteric peptide hormones between pH 2 and 12 in polybrene-coated capillaries. Polybrene (hexadimethrin bromide) is a polymer composed of quaternary amines that is strongly adsorbed by the fused-silica inner surface, preventing undesired interactions between the peptides and the inner capillary wall. In polybrene-coated capillaries the separation voltage must be reversed, because of the anodic electroosmotic flow promoted by the polycationic polymer attached to the inner capillary wall. The possibility of using polybrene-coated capillaries for determination of accurate ionization constants has been evaluated and the optimum pH for separation of a mixture of the peptide hormones studied has been selected. Advantages and disadvantages of using bare fused-silica and polybrene-coated capillaries for these purposes are discussed.
authors.affiliation: Department of Analytical Chemistry, University of Barcelona, Diagonal 647, 08028 Barcelona, Spain.
authors.forename: Ghiulendan
authors.initials: G
authors.lastname: Aptisa
authors.forename: Fernando
authors.initials: F
authors.lastname: Benavente
authors.forename: Victoria
authors.initials: V
authors.lastname: Sanz-Nebot
authors.forename: Elisabeta
authors.initials: E
authors.lastname: Chirila
authors.forename: José
authors.initials: J
authors.lastname: Barbosa
mesh_terms: D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D053841:Electroosmosis; D019075:Electrophoresis, Capillary; D006583:Hexadimethrine Bromide / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008956:Models, Chemical; D036361:Peptide Hormones / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D020099:Coated Materials, Biocompatible; D036361:Peptide Hormones; D006583:Hexadimethrine Bromide