Search Results

You are looking at 1 - 6 of 6 items for

  • Author or Editor: V. Spěváčková x
  • All content x
Clear All Modify Search

Abstract  

Stability and distribution constants of thallium(I) ethyl, n-propyl, isopropyl, n-butyl, isobutyl and sec-butyl xanthates have been radiometrically determined using ion-exchange and extraction methods. The length of the alkyl chain influences the distribution constant, however, it has only a small effect on the stability constant.

Restricted access

Abstract  

The determination of gold in platinum by neutron activation analysis is described. The possibility of screening out the influence of the nuclear reactions

\documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{upgreek} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} $${}^{196}Pt(n,\gamma )^{197} Pt\xrightarrow{{\beta ^ - }}{}^{197}Au$$ \end{document}
on the final result of the determination was studied. In the case of microamounts of gold in platinum, gold was separated previously by extraction chromatography with dithizone as organic stationary phase. Gold fixed on the column was irradiated and determined gamma-spectrometrically.

Restricted access

Abstract  

The paper describes a procedure for the determination of uranium in dilute solutions by fluorescence method. Factors influencing the determination in a phosphoric acid medium were studied. The detection limit of uranium determination is 0.04–0.05 ppm.

Restricted access

Abstract  

The determination of uranium in solutions and sorbents by measurement of absorption of soft gamma-rays is described. The use of 22 keV gamma-rays of109Cd enbled us to improve the sensitivity of the determination for nearly an order of magnitude when compared to the measurements using241Am source. The application to the continuous measurement of uranium concentration in pilot-plant streams and of concentration profiles of uranium sorbed on columns of ion exchangers is described.

Restricted access

Abstract  

The determination of uranium in natural waters by XRF analysis after its preconcentration with some organic precipitants is described.109Cd source is used for the excitation of L-series X-rays of uranium. Separation yield, kinetics of coprecipitation and the possibility of preparing thin-layer samples for XRF analysis were studied in detail for uranium concentration with α-nitroso-β-naphtol, methylene blue with ammonium thiocyanate, tannin with urotropine and other precipitants. A procedure using coprecipitation of uranium with α-nitroso-β-naphtol from 500 ml samples of surface or waste, waters is proposed.

Restricted access

Abstract  

Problems of the extraction of zinc from soil with solutions of alkaline earth chlorides, sodium and ammonium acetate, EDTA and aqueous solutions of HClO4 or NaOH with low ionic strength at various pH has been studied using radiotracer65Zn. The strong influence of pH on extraction from chloride, acetate and aqueous solutions has been proved. No difference due to the counter ions in chloride extractants has been observed. The distribution coefficient of zinc between soil and the aqueous phase was not influenced by the V/m ratio.

Restricted access