title: Study of electromigration effects on a pH boundary during the on-line electrokinetic preconcentration by capillary electrophoresis.
abstract: A contribution to the description of electrokinetic effects on the pH boundary formed by sodium borate pH 9.5 and sodium phosphate pH 2.5 electrolytes for on-line preconcentration of weak acids is presented in this article. Simulations of electrokinetic injections together with experimental studies using contactless conductivity detection verified that the preconcentration is induced mainly by dissociation changes of analytes on the pH boundary and transient ITP state. Moreover, a study of the addition of organic solvent to the injection electrolyte was performed with impressive results. Subnanomolar LODs of hydroxybenzoic acids were achieved with 80% of methanol in the injection electrolyte which represents more than 70 000-fold preconcentration in comparison with classical CZE method.
authors.affiliation: Department of Analytical Chemistry, Faculty of Science, Palacký University in Olomouc, Olomouc, Czech Republic.
authors.forename: Katerina
authors.initials: K
authors.lastname: Vítková
authors.forename: Jan
authors.initials: J
authors.lastname: Petr
authors.forename: Vítezslav
authors.initials: V
authors.lastname: Maier
authors.forename: Joanna
authors.initials: J
authors.lastname: Znaleziona
authors.forename: Juraj
authors.initials: J
authors.lastname: Sevcík
mesh_terms: D019817:Benzoic Acid / Q000737:chemistry / Q000302:isolation & purification; D001888:Boric Acids / Q000737:chemistry; D002197:Capillary Action; D004553:Electric Conductivity; D004573:Electrolytes / Q000302:isolation & purification*; D019075:Electrophoresis, Capillary / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D000432:Methanol; D009862:Online Systems; D009930:Organic Chemicals / Q000737:chemistry; D009994:Osmolar Concentration; D010756:Phosphoric Acids / Q000737:chemistry; D012822:Silicon Dioxide; D012997:Solvents / Q000737:chemistry
chemical_list: D001888:Boric Acids; D004573:Electrolytes; D009930:Organic Chemicals; D010756:Phosphoric Acids; D012997:Solvents; D012822:Silicon Dioxide; D019817:Benzoic Acid; C030242:phosphoric acid; C032688:boric acid; D000432:Methanol