This paper describes the development of an electrophoretic method used to a
nalyse seven water-soluble vitamins, and its use in the analysis of pharmac
eutical formulations. Thiamine, nicotinamide, nicotinic acid, pyridoxine, a
scorbic acid, folic acid and riboflavin were separated from one another in
7 min by micellar electrokinetic capillary chromatography using a carrier c
ontaining sodium dodecyl sulphate as surfactant, and were subsequently dete
cted spectrophotometrically using a diode-array detector. The limits of det
ection (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.