Simultaneous Separation and Identification of Cyanocobalamin, Thiamine, and Ascorbic Acid on Polyoxyethylene Sorbitan Monooleate-lmpregnated Silica Layers with Water as Mobile Phase

摘要

A thin-layer chromatographic system comprising a silica layer impregnated with nonionic surfactant (2% Cween 80) as stationary phase and double-distilled water as mobile phase was identified as the most favorable system for mutual separation of the water-soluble vitamins thiamine, cyanocobalamin, and ascorbic acid. The presence of inorganic anions and metal cations as impurities in the sample, the effect of different solvents of the analyte, and the effects of pH of sample and mobile phase were examined for separation of the three-component mixture. It was possible to separate micro-gram amounts of thiamine from milligram amounts of cyanocobalamin and vice versa. The stability of the mixture of thiamine, cyanocobalamin, and ascorbic acid; the relative standard deviation of the R_F values of separated components of the mixture; and the lowest detectable amounts of the three vitamins were determined. The proposed thin-layer chromatographic method is suitable for identification and separation of thiamine, cyanocobalamin and ascorbic acid in drug samples.