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  • Author or Editor: M. Abuzwida x
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Abstract  

The simultaneous determination of U(VI), Pu(VI), Pu(V) in 0.5–4.0 M NaOH has been elaborated by means of classical and differential pulse voltamperometry. U(VI) is determined with a dropping mercury electrode (DME) at the half-wave potential of E1/2=–0.89 V vs. Ag/AgCl reference electrode due to reduction to U(V). The limiting current or peak heights are proportional to uranium(VI) concentration in the range of 1.3.10–7–3·10–4 M U(VI). Deviation from proportionality is observed for higher concentrations due to polymerization of uranates. Pu(VI) and Pu(V) are determined with a platinum rotating electrode at E1/2=–0.02 V due to the reaction Pu(VI)+e»Pu(V) and with DME at E1/2=–1.1 V due to the reduction to Pu(III). The limiting currents of both Pu(VI) and Pu(V) are proportional to their concentrations in the range of 4·10–6–1.2·10–3 M Pu. The determination of U(VI), Pu(VI), Pu(V) is not interfered by the presence of the following salts: 2M NaNO3, 2M NaNO2, 1.5M NaAlO2, 0.5M NaF and ions of Mo(VI), W(VI), V(V), Cu(II). The presence of CrO 4 2– and FeO 2 ions disturbs the determination of U(VI) in 1–4M NaOH, however, contribution of the reaction Fe(III)+e»Fe(II) to uranium reduction peak can be calculated from the height of the second peak Fe(II)+2 e»Fe(0).

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Abstract  

A selective liquid scintillation method is suggested for plutonium determination by alpha-spectrometry in the presence of uranium. The analytical process consists of extracting plutonium from nitric acid solutions using BPHA, TOA and MTOA nitrate as extractants into toluene scintillator. Effect of various extractants and nitric acid concentration on the extraction of Pu(IV) and U(VI) together with scintillations quenching were investigated. A simple and fast two-stage selective scintillation method is also suggested for Pu determination in the irradiated uranioum samples.

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