WATER-IN-OIL MICROEMULSION AS MOBILE-PHASE IN THIN-LAYER CHROMATOGRAPHIC RETENTION STUDIES OF ANIONS

A water-in-oil (W/O) microemulsion, consisting of sodium dodecyl sulph ate (SDS)/1-pentanol/water/heptane, has been used as mobile phase for the separation of inorganic anions from their binary mixtures, for exa mple, IO4-NO2-, IO4-BrO4-, IO4--I-, MnO4-BrO3-, MnO4-NO2-, and MnO4-Br -. The weight ratio, SDS/n-pentanol was kept constant at 1/2.46 for al l compositions. The retention efficiency of anions on layers of silica gel G, alumina, microcrystalline cellulose, kieselguhr G, and mixture s of kieselguhr and cellulose in 4:1 and 3:2 ratios has been examined with the W/O microemulsion system as a mobile phase. Thin layers of ki eselguhr were most useful for differential migration of anions. Quanti tative separation of IO4- from accompanying ions, limits of identifica tion, and dilution of few anions are reported. The effects of amines, phenols, and heavy metals on the separation efficacy of IO4- also have been investigated.