title: Determination of pKa values of organic bases in aqueous acetonitrile solutions using capillary electrophoresis.
abstract: Capillary electrophoresis (CE) was used for the determination of ionisation constants (pKa) of a variety of organic bases in aqueous acetonitrile solutions over the range 0-60% (v/v) acetonitrile. These bases are used as test compounds in HPLC column evaluation, thus knowledge of their pKa in hydro-organic solutions is useful. The base pKa decreased with acetonitrile concentration and significant shifts from the aqueous pKa (up to -0.8) were found using 60% acetonitrile. The CE application was confirmed to be very suitable for fast and accurate pKa measurement in aqueous organic solutions.
authors.affiliation: Centre for Research in Analytical Methods and Sensors, University of the West of England, Frenchay, Bristol BS16 1QY, UK.
authors.forename: Stephan M C
authors.initials: SM
authors.lastname: Buckenmaier
authors.forename: David V
authors.initials: DV
authors.lastname: McCalley
authors.forename: Melvin R
authors.initials: MR
authors.lastname: Euerby
mesh_terms: D000097:Acetonitriles / Q000737:chemistry*; D002021:Buffers; D019075:Electrophoresis, Capillary / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D009930:Organic Chemicals / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D000097:Acetonitriles; D002021:Buffers; D009930:Organic Chemicals; D014867:Water; C032159:acetonitrile