Reversed-phase Chromatography of Amines, Phenols, and Metal Cations on Silica Layers Impregnated with Tributyl Phosphate, Using Surfactant-mediated Mobile Phases

The analytical potential of tri-n-butyl phosphate (TBP) as impregnant in the thin-layer chromatographic separation of mixtures of amines, phenols, or metal ions has been investigated. Silica gel impregnated with 0.001 M TBP as stationary phase and an aqueous micellar solution (0.01 M) of CTAB, a cationic surfactant, as mobile phase was found to be the best chromatographic system for achieving important separations of metal cations (e.g. Cr from Cr, Fe from Mn and Cr, VO from Mn and Cr) and phenols (e.g. o-cresol from m-cresol, m-aminophenol from o-aminophenol) from their mixtures. An aqueous solution (8.3 × 10 M) of the non-ionic surfactant, Brij-35 proved suitable for achieving good separations of amines (e.g. p-dimethylaminobenzaldehyde from L-tryptophan, p-dimethylaminobenzaldehyde from indole) on silica layers impregnated with 0.001 M TBP. The effect of metal cations on the separation of amines and phenols was examined, as was the effect of amines and phenols on the separation of metal ions. The effect of foreign substances on the separation of analytes was marginal.