Plain and ion-pair thin-layer chromatography of synthetic dyes on an admixture of silica gel G and barium sulfate in an aqueous ethanol system.

An easy, inexpensive, and accurate method for the analysis of synthetic dyes by means of ion-pair thin-layer chromatography (IPTLC) on mixed sorbent phases containing silica gel G and barium sulfate in an aqueous ethanol system is studied. The effect of the composition of the sorbent phases has a major effect on the hundred-fold relative migration rate, as also does the effect of the ion-pairing reagent as the impregnant. Compact and sharp spot application yields very good binary and ternary separations and enables their clear identification. IPTLC has better separations on mixed sorbent phases, which are not possible on plain mixed phases in thin-layer chromatography. The method can be applied for the trace analysis of synthetic dyes in various natural and synthetic samples.