Using high-performance liquid chromatography it has been possible to separate 14 lanthanide elements in less than 40 min by elution with an ahydroxyisobutyric acid concentration gradient. LiChrosorb KAT cation exchanger (10 pm) is used as the packing material and the eluted lanthanides are detected with an ultraviolet detector after complexation with Arsenazo 111. The detection limit is about 0.1 pg.Determinations of the rare-earth composition in monazite sand and .rareearth impurities in high-purity lanthanum(III), cerium(IV), samarium(II1) and yttrium(II1) oxides were carried out. The proposed method is more convenient than others, and the separation of major components is not necessary in analyses of high-purity rare earths; the elution time is only about 1 h.
Granular entrapped adsorbents of crown etherphosphotungstic acid (PW) and crown etherphosphomolybdic acid (PMo) in polyacrylamide were prepared by the solgel method and used for the adsorption of various heavy metals ions such as Ag+, Pb2+, Hg2+, Cd2+, Fe3+ and Zn2+. Dibenzo-18-crown-6 -PW (or -PMo)/polyacrylamide adsorbent gave high adsorption and a high selectivity for large metal ions such as Ag+, Pb2+ and Hg2+, but not for smaller ions. In contrast, small heavy metal ions such as Cu2+, Fe3+ and Zn2+, but not larger ions, were strongly adsorbed by 12-crown-4 -PW (or -PMo)/polyacrylamide adsorbent. The effects of pH and solvents on the adsorption were investigated. A dibenzo-18-crown-6 -PMo adsorbent film was also prepared and successfully applied to the selective adsorption of Ag+ ions from an aqueous solution containing various metal ions, and the Ag+ ions on the film could be determined quantitatively by X-ray fluorescence analysis.
The mixture of metal ions [Bi(III), Fe(III), Fe(II), Cu(II), Zn(II), Ni(II), Co(II), Pb(II), Cd(II), Mn(II)] were separated in the bonded‐phase strong cation exchange column (Vydac‐401 SA) and monitored at 540 nm after a postcolumn reaction with 4‐(2‐pyridylazo)‐resorcinol (PAR). Citrate, tartrate, lactate and α‐hydroxyisobutyrate buffer were used as eluent and it has been found that the elution order of some metal ions were changed with different eluents. The detection limits and the calibration curves of metal ions were also studied.
A method for the determination of trace molybdenum in uranium is described based on its specific catalytic reduction wave in the presence of nitric acid. Molybdenum is separated from uranium by α‐benzoin oxime extraction and determined by differential pulse polarography. As lower as 1 ng/ml of Mo(VI) is determinable and 98% of recovery can be obtained at present work.
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