Separation and determination of Vitamins E and A in multivitamin syrup using micellar liquid chromatography and simplex optimization.

A rapid method has been described for separation and determination of Vitamins A and E using micellar liquid chromatography (MLC). Influence of temperature of column and addition of organic modifiers on separation efficiency was investigated. A temperature of 30 degrees C and 1-butanol modifier was selected. Optimization of the parameters affecting the separation including percent of organic modifier, pH of the mobile phase, concentration of surfactant, and flow rate of the mobile phase was performed simultaneously using the super-modified simplex (SMS) procedure. Results showed that 11.7% 1-butanol, 76.9 mM sodium dodecyl sulphate (SDS), pH of 6.73 and a flow rate of 1.35 ml min(-1) are the best conditions for separation of these compounds. The analytical parameters including linearity, r>0.9990; limit of detection 1.71 and 4.52 microg ml(-1) for A and E, respectively; precision of the method, R.S.D.<2.85%; and recovery, more than 90%, show that the method is useful for measuring these compounds in pharmaceutical preparations.