Dynamic and static modification of stationary phases with surfactants in TLC: A comparative study

Dynamic and static modification of normal (Silufol) and C-3-reversed-phase (Plasmachrom) TLC stationary phases with anionic, cationic, and nonionic su rfactants have been studied by using fluorescein and erythrosin as probes, The use of cationic and anionic surfactant micelles has been found to resul t in dynamic modification of the plate surface, which acquires reversed-pha se properties. The suitability of methanol solutions of cationic and nonion ic surfactants for preliminary modification (impregnation) of TLC plates un der static conditions before separation of the dyes with methanol-water mob ile phases has been demonstrated. The effects of mobile phase acidity and t he nature and concentration of the surfactant and the dye have been investi gated and are discussed, The possibility of separation of fluorescein and e rythrosin by TLC with micellar mobile phases comprising cetylpyridinium chl oride and sodium dodecylsulfate has been shown.