Investigation and optimisation of the use of organic modifiers in micellar electrokinetic chromatography

Abstract

The effect of organic modifiers (methanol, ethanol, propan-2-ol, butan-1-ol, butan-2-ol, acetone, methyl ethyl ketone and acetonitrile) on the micellar electrokinetic chromatographic (MEKC) resolution and migration time of seven model compounds has been investigated. The compounds used were all drugs reported to have cardiovascular antiarrhythmic activity, The organic modifiers have each been investiated at 5, 10 and 15% (v/v) of the electrophoretic buffer (100 m M borate buffer pH 8.1 containing 50 m M SDS as surfactant), to determine the optimum resolution and peak shape. The elution order under almost every condition corresponded to increasing molecular mass of the analyte drugs. Propan-2-ol at a concentration of 10% (v/v) gave optimum separation of the analytes. Replicate injections under these conditions gave excellent precision data for the migration time and corrected peak area. Other modifiers which gave baseline resolution of the analytes but less precise repeatability data were acetone and methyl ethyl ketone.