Micellar electrokinetic capillary chromatography analysis of water-soluble vitamins

This paper describes the development of an electrophoretic method used to analyse seven water-soluble vitamins, and its use in the analysis of pharmaceutical formulations. Thiamine, nicotinamide, nicotinic acid, pyridoxine, ascorbic acid, folic acid and riboflavin were separated from one another in 7 min by micellar electrokinetic capillary chromatography using a carrier containing sodium dodecyl sulphate as surfactant, and were subsequently detected spectrophotometrically using a diode-array detector. The limits of detection (S/N = 3) ranged between 0.08 mu g ml(-1) for folic acid and 0.25 mu g ml(-1) for nicotinamide and thiamine. The relative standard deviation of the proposed method was less than 6% for all formulation samples. (C) 1999 Elsevier Science B.V. All rights reserved.