Determination of pKa values of organic bases in aqueous acetonitrile solutions using capillary electrophoresis.
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.
Buckenmaier
Stephan M C
SM
Centre for Research in Analytical Methods and Sensors, University of the West of England, Frenchay, Bristol BS16 1QY, UK.
McCalley
David V
DV
Euerby
Melvin R
MR
D000097:Acetonitriles / Q000737:chemistry*; D002021:Buffers; D019075:Electrophoresis, Capillary / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D009930:Organic Chemicals / Q000737:chemistry*; D014867:Water / Q000737:chemistry
D000097:Acetonitriles; D002021:Buffers; D009930:Organic Chemicals; D014867:Water; C032159:acetonitrile