Shuji Ninomiya

Thin-layer chromatographic behaviour and separation of rare earths on silica gel in aqueous ammonium nitrate solution

The thin-layer Chromatographic behaviour of all the rare earths except promethium on silica gel in aqueous ammonium sulfate solutions of varying concentrations has been investigated. Generally, the Rf-values of each rare earth except scandium increase with increasing concentration of the salt, and those for the lanthanoids decrease in a regular way with increasing atomic number(Z). At lower salt concentrations, the tetrad effect pointed out by Peppard et al. [2] is clearly found in the variations of both the Rf-values and the logarithm of the separation factors relative to Gd with Z. The present system permits good separations of adjacent pairs of the lanthanoids, especially heavier ones (Ho to Lu), from each other. Typical chromatograms for the separation of multi-component mixtures are presented.

Thin-layer chromatographic behaviour and separation of rare earths in silica gel-aqueous alkali metal chloride systems

SummaryThe thin-layer Chromatographic behaviour of all rare earths except Pm on silica gel in aqueous alkali metal nitrate solutions has been investigated. In all the solutions the tetrad effect is clearly observed in the variations of both the Rf-values and the logarithms of the separation factors relative to Gd with the atomic numbers of the lanthanoids. A brief discussion concerning the effect of the solvent cations and typical chromatograms for the separations of multicomponent mixtures containing adjacent lanthanoids are presented.

Thin-layer chromatographic behaviour and separation of zirconium(IV) and hafnium(IV) on silica gel in mineral acid—hydrogen peroxide media

Abstract The thin-layer chromatographic behaviour of Zr(IV) and Hf(IV) on silica gel in HNO3, HCl and H2SO4 media containing various amounts of H2O2 was investigated as a function of the concentration of each component of the respective solvents. In all the systems, Zr(IV) gave much higher RF values than Hf(IV) because of the stronger complexation of Zr(IV) with H2O2, so that the complete separation of the two metals, present in Zr:Hf weight ratios ranging from 20:1 to 1:40, could be accomplished simply and easily without any sample pretreatment.

Thin-layer chromatographic behaviour and separation of rare earths on silica gel in aqueous ammonium sulfate solution@@@Dnnschicht-chromatographisches Verhalten und Trennung von Seltenen Erden an Silicagel in wriger Ammoniumsulfatlsung

SummaryThe thin-layer Chromatographic behaviour of all the rare earths except promethium on silica gel in aqueous ammonium sulfate solutions of varying concentrations has been investigated. Generally, the Rf-values of each rare earth except scandium increase with increasing concentration of the salt, and those for the lanthanoids decrease in a regular way with increasing atomic number(Z). At lower salt concentrations, the tetrad effect pointed out by Peppard et al. [2] is clearly found in the variations of both the Rf-values and the logarithm of the separation factors relative to Gd with Z. The present system permits good separations of adjacent pairs of the lanthanoids, especially heavier ones (Ho to Lu), from each other. Typical chromatograms for the separation of multi-component mixtures are presented.

Anion-exchange separation of rhodium and iridium by ECTEOLA-cellulose column

SummaryThe separation of Rh(III) and Ir(IV) in amounts of 20–5300 and 20–7700 μg, respectively, and in ratios of Rh∶Ir=1∶100 to 100∶1 was achieved without cross-contamination by use of a 3 g ECTEOLA-cellulose column. Rh was first eluted with 40 ml of a 3 mol/l HCl-1% (w/v) NaClO3 solution. Ir(IV) was desorbed with 60 ml of a 6 mol/l HCl-0.1% (w/v) NaClO3 solution. Quantitative recoveries were obtained for each metal. The present method provides much better resolution than the other existing anion-exchange methods and can effectively be applied to the separations and recoveries of Rh and Ir(III or IV) present in a more extensive range of amounts and ratios.