Normal- and reversed-phase thin layer chromatography of fluorescein dyes with aqueous micellar solutions as mobile phases

The chromatographic separation of ten fluorescein dyes has been studied on normal- (Silufol) and reversed-phase (Plasmachrom) stationary phases with m icellar solutions of cationic, anionic and nonionic, surfactants as mobile phases, The use of cationic and anionic surfactants has been found to resul t in dynamic modification of the silica gel surface, with the result that i t acquires reversed-phase properties. The effects of mobile-phase acidity, the nature and concentration of the surfactant and the dye have been invest igated. The possibility separating the fluorescein dyes by TLC with micella r mobile phases comprising cetylpyridinium chloride and sodium dodecylsulfa te, and the use of the method for purity control, has been shown. Partition coefficients have been calculated for several dyes in the system water-SDS micelle.