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61.
62.
Yutaka Hayashibe Mayumi Kurosaki Fumiyasu Takekawa Rokuro Kuroda 《Mikrochimica acta》1989,98(4-6):163-171
Methods were developed for the determination of gallium and indium in complex ores by electrothermal-atomization atomic absorption Spectrometry using matrix modifications. Nickel and nickel-ammonium sulfate as matrix modifier has enhanced the absorption signals for gallium and indium, respectively, eliminating the matrix interferences to allow their solutions in nitric acid to be used as calibration standards. No matrix separations are necessary. Results are quoted for a variety of black ore samples (Kuroko). The RSDs are 7.0% for gallium and 5.3% for indium at their 10 g/g levels, and the inverse sensitivities are 20 pg of gallium and 38 pg of indium for respective 1% absorption. 相似文献
63.
Platinum(IV) and palladium (II) are strongly adsorbed on the weakly basic cellulose ion exchanger DEAE from dilute thiocyanate media, while most other metal ions do not show any marked tendency to adsorb from the same media. It is possible to separate and concentrate the noble metal ions from a large quantity of base metals such as iron, cobalt, nickel, copper, zinc and lead. As little as 1 mg of platinum(IV) and/or palladium (II) can be quantitatively separated from as much as 20–25 g of base metals on a small column of DEAE (thiocyanate form). The noble metal ions adsorbed are easily stripped from DEAE. 相似文献
64.
Summary A preconcentration technique involving anion-exchange in a thiocyanate medium has been developed for the determination of traces of vanadium, cobalt, copper, zinc, and cadmium in sea water. A conventional, small column containing a strongly basic anionexchange resin Amberlite CG 400 in the thiocyanate form allows the five trace metals to be concentrated from a 11 of sea water sample adjusted to 0.1M in thiocyanate and 0.1M in hydrochloric acid. Sorbed metals can be recovered simultaneously by elution with 140 ml of 2M perchloric acid. A stepwise elution technique is also developed, which permits removal of vanadium-copper-cobalt as a group, zinc, and cadmium to improve the selectivity of the separation. A simple scheme of separation for vanadium, copper, and cobalt is given, so that spectrophotometric determinations of these metals even with nonselective reagents may be feasible. Results are quoted on the preconcentration and subsequent spectrophotometric determination of the five metals in brine and sea waters. 相似文献
65.
A neutron activation method is proposed for the determination of rhenium in rocks and ores. After the irradiation, the radiochemical separation consists of a one-step anion exchange; β-activities of radiochemically pure 188Re or 186Re are counted. The chemical yield averaged 75% and there was a considerable saving of time in the radiochemical work. Results are quoted for the rhenium contents of the standard rock W-1, several molybdenites and pyrolusites. 相似文献
66.
Rokuro Kuroda Yutaka Hayashibe Kenichi Yoshitsuka 《Fresenius' Journal of Analytical Chemistry》1990,336(6):494-497
Summary The application of first-derivative spectrometry to the simultaneous determination of palladium(II), platinum(IV) and gold(III) is described. Light absorption of stable chlorocomplexes formed in 1 mol/l hydrochloric acid provides the basis of their determinations. A difference in the derivative amplitudes between two first-derivative zero crossing points of one metal A is read, corrected for the contribution of metal B and used for quantitation of metal C. Palladium (0.48–20 g ml–1), platinum (0.16–24 g ml–1) and gold (0.32–24 g ml–1) have been determined with good precision and accuracy without any separations. Results are also presented for the simultaneous determination of the three precious metals in the presence of several major constituents. 相似文献
67.
The anion exchange of rare earths(III), thorium(IV), protactinium(V) and uranium (VI) from thiocyanate-chloride media was investigated. The equilibrium, distribution study showed that the rare earths(III) and yttrium(III) were not significantly adsorbed on a basic anion-exchangc resin, while thorium(IV), protactinium(V) and uranium(VI) were strongly adsorbed. Adsorption from the thiocyanate-chloride solutions is in the order, U(Vl) > Pa(V) > Th(IV). The separation of rare earths(III) or yttrium(III), thorium(IV), protactinium(V) and uranium(VI) was successfully accomplished by column elution in thiocyanate-chloride media. A rapid and effective ion-exchange method for separating protactinium-233 from irradiated thorium(IV) is also presented. 相似文献
68.
The adsorption characteristics for 43 metals on a strongly basic ion-exchange resin Bio-Rad AG1 were examined in 0.5 M hydrazoic acid solution. The distribution coefficients for V(IV), Fe(III), Cu(II), Zn, Se(IV), Mo(VI), Pd(II), Cd, In(III), Rc(VII), Hg(II) and U(VI), which showed very strong adsorption except for Cd, were measured as a function of hydrazoic acid concentration over the range 0.05–0.5 M. Favorable differences in the distribution coefficients allow useful two- and three-component separations such as Co(II)-Fe(III), As(III)-V(IV), Cd-Zn, Cd- Hg(II), Te(IV)-Se(IV), Th-U(VI), Mn(II)-Mo(VI)-Re(VII), to be achieved on a small column. 相似文献
69.
The adsorption behaviour of forty-eight metals on DEAE-cellulose thin layers has been examined in aqueous phosphoric acid media. RF values are given as a function of phosphoric acid concentration over the range 0.01–1.0 M and are compared with those obtained in a similar manner with a crystalline cellulose, Avicel SF. Particularly strong retention on DEAE-cellulose occurred for Mo(VI), W(VI), Re(VII), the platinum group metals, Au(III) and Bi(III). Weak to moderate retention was also observed for several metals, such as V(V), Fe(III), Se(IV), In(III), the rare earths and U(VI), at lower concentrations of phosphoric acid (<0.1 M). 相似文献
70.