Analysis of B6 vitamers by micellar electrokinetic capillary chromatography with laser-excited fluorescence detection.

Micellar electrokinetic capillary chromatography (MECC) involves the application of a high voltage (10 to 40 kV) across a capillary column (25 to 75 microns i.d.) that is filled with a solution containing micelles. The mobile phase in this work consists of sodium dodecyl sulfate in an aqueous phosphate/borate buffer system. Pyridoxine (vitamin B6) and five of its metabolites are separated, with efficiencies as high as 60,000 theoretical plates/meter. Pyridoxic acid, a metabolite of B6, is separated and quantitated in human urine using laser-excited fluorescence detection. Limits of detection are less than a picogram injected.