Determination of ionisation constants of organic bases in aqueous methanol solutions using capillary electrophoresis.
The pKa of eight organic bases was determined in aqueous and aqueous methanol solutions of 0-70% (v/v) methanol using capillary electrophoresis. The bases investigated include compounds commonly used to test the activity of RP columns in HPLC. The variation of pKa with temperature in aqueous methanol solutions was also investigated and found to closely resemble temperature coefficients reported for bases in purely aqueous solutions. pKa values determined by CE were compared to those reported using NMR spectroscopy. The good agreement of the results is evidence that either technique is suitable to perform pKa measurements.
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; D002851:Chromatography, High Pressure Liquid; D019075:Electrophoresis, Capillary; D006863:Hydrogen-Ion Concentration; D007477:Ions / Q000737:chemistry; D007700:Kinetics; D000432:Methanol / Q000737:chemistry*; D015394:Molecular Structure; D009930:Organic Chemicals / Q000737:chemistry*; D012996:Solutions / Q000737:chemistry; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
D000097:Acetonitriles; D007477:Ions; D009930:Organic Chemicals; D012996:Solutions; D014867:Water; D000432:Methanol; C032159:acetonitrile