Optimization of the separation of flavonoids by micellar electrokinetic capillary chromatography:: Effect of organic solvents

A group of flavonoids of special interest to wine qualify were separated by micellar electrokinetic chromatography (MEKC) with diode array detection. Their separation was optimized as a function of the buffer concentration and pH, the concentration of sodium dodecyl sulfate (SDS) and the applied voltage. Selectivity and resolution of the solutes were increased by adding organic solvents to the separation buffer, the best results being obtained at lower concentrations. An optimized buffer with 5% methanol provided optimum separation with regard to efficiency resolution and migration time. The optimized method was applied to the determination of these compounds in wine samples.