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Direct spectroscopic speciation of the complexation of U(VI) in acetate solution.

Meinrath G, Kwiatek D, Hnatejko Z, Lis S - Monatsh. Chem. (2014)

Bottom Line: Using chemometric data analysis, the resulting factor structure was evaluated to obtain a subset of 14 spectra holding only one coordinated species next to UO2 (2+) (aq).The molar absorption coefficient for the U(VI) monoaceto species was estimated as ε 418 = 17.8 ± 1 dm(3) mol(-1) cm(-1).Spectral deconvolution was used to obtain an estimate of the species concentrations which allowed to calculate for each sample the free acetate concentration, the total U(VI) amount and, eventually, to estimate the formation quotient lg β 11 = 2.8 ± 0.3 of UO2(CH3COO)(+).

View Article: PubMed Central - PubMed

Affiliation: RER Consultants, Fuchsbauerweg 50, 94036 Passau, Germany.

ABSTRACT

Abstract: As a result of systematic UV-Vis absorption spectroscopy studies in the U(VI) acetate system, the single component spectrum of [UO2CH3COO](+) with characteristic parameters was evaluated and applied in quantitative deconvolution of multicomponent spectra. Free acetate concentrations were obtained by the use of geochemical and probabilistic modelling codes. A total of 51 UV-Vis spectra were collected in a wide range of experimental conditions where coordination of U(VI) by acetate ion was indicated by characteristic variations in the spectra structure as compared to UO2 (2+). Using chemometric data analysis, the resulting factor structure was evaluated to obtain a subset of 14 spectra holding only one coordinated species next to UO2 (2+) (aq). The molar absorption coefficient for the U(VI) monoaceto species was estimated as ε 418 = 17.8 ± 1 dm(3) mol(-1) cm(-1). Spectral deconvolution was used to obtain an estimate of the species concentrations which allowed to calculate for each sample the free acetate concentration, the total U(VI) amount and, eventually, to estimate the formation quotient lg β 11 = 2.8 ± 0.3 of UO2(CH3COO)(+).

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Single component spectrum of UO2CH3COO+, compared to the spectrum of UO22+(aq). Absorption maximum of the characteristic band of U(VI) is found at 418.0 nm. Molar absorption ε418 = 17.8 ± 1.0 dm3 mol−1 cm−1. Dashed lines give upper and lower 0.68, dotted lines 0.95 ‰ uncertainty obtained from moving block bootstrap analysis
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Fig4: Single component spectrum of UO2CH3COO+, compared to the spectrum of UO22+(aq). Absorption maximum of the characteristic band of U(VI) is found at 418.0 nm. Molar absorption ε418 = 17.8 ± 1.0 dm3 mol−1 cm−1. Dashed lines give upper and lower 0.68, dotted lines 0.95 ‰ uncertainty obtained from moving block bootstrap analysis

Mentions: The single component spectrum of UO2CH3COO+ resulting from these analyses is shown in Fig. 4, together with the spectrum of UO22+(aq) for comparison. The monoacetato species shows an absorption maximum at 418.0 nm with a molar absorption coefficient ε418 = 17.8 ± 1 dm3 mol−1 cm−1. The spectrum is given in Fig. 4 together with 0.68 ‰ (dashed) and 0.95 ‰ (dotted), obtained from a moving block bootstrap analysis [36]. Within the limits of precision, the UV–Vis absorption spectrum of UO2CH3COO+ does not show a shift in the absorption maximum or the bands/shoulders in the characteristic absorption region of U(VI) compared to the absorption spectrum of UO22+ except in the absorption maximum. The small difference in the position of the absorption maximum of the characteristic band of U(VI) causes the shift observed with the experimental spectra in Fig. 2.Fig. 4


Direct spectroscopic speciation of the complexation of U(VI) in acetate solution.

Meinrath G, Kwiatek D, Hnatejko Z, Lis S - Monatsh. Chem. (2014)

Single component spectrum of UO2CH3COO+, compared to the spectrum of UO22+(aq). Absorption maximum of the characteristic band of U(VI) is found at 418.0 nm. Molar absorption ε418 = 17.8 ± 1.0 dm3 mol−1 cm−1. Dashed lines give upper and lower 0.68, dotted lines 0.95 ‰ uncertainty obtained from moving block bootstrap analysis
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4495045&req=5

Fig4: Single component spectrum of UO2CH3COO+, compared to the spectrum of UO22+(aq). Absorption maximum of the characteristic band of U(VI) is found at 418.0 nm. Molar absorption ε418 = 17.8 ± 1.0 dm3 mol−1 cm−1. Dashed lines give upper and lower 0.68, dotted lines 0.95 ‰ uncertainty obtained from moving block bootstrap analysis
Mentions: The single component spectrum of UO2CH3COO+ resulting from these analyses is shown in Fig. 4, together with the spectrum of UO22+(aq) for comparison. The monoacetato species shows an absorption maximum at 418.0 nm with a molar absorption coefficient ε418 = 17.8 ± 1 dm3 mol−1 cm−1. The spectrum is given in Fig. 4 together with 0.68 ‰ (dashed) and 0.95 ‰ (dotted), obtained from a moving block bootstrap analysis [36]. Within the limits of precision, the UV–Vis absorption spectrum of UO2CH3COO+ does not show a shift in the absorption maximum or the bands/shoulders in the characteristic absorption region of U(VI) compared to the absorption spectrum of UO22+ except in the absorption maximum. The small difference in the position of the absorption maximum of the characteristic band of U(VI) causes the shift observed with the experimental spectra in Fig. 2.Fig. 4

Bottom Line: Using chemometric data analysis, the resulting factor structure was evaluated to obtain a subset of 14 spectra holding only one coordinated species next to UO2 (2+) (aq).The molar absorption coefficient for the U(VI) monoaceto species was estimated as ε 418 = 17.8 ± 1 dm(3) mol(-1) cm(-1).Spectral deconvolution was used to obtain an estimate of the species concentrations which allowed to calculate for each sample the free acetate concentration, the total U(VI) amount and, eventually, to estimate the formation quotient lg β 11 = 2.8 ± 0.3 of UO2(CH3COO)(+).

View Article: PubMed Central - PubMed

Affiliation: RER Consultants, Fuchsbauerweg 50, 94036 Passau, Germany.

ABSTRACT

Abstract: As a result of systematic UV-Vis absorption spectroscopy studies in the U(VI) acetate system, the single component spectrum of [UO2CH3COO](+) with characteristic parameters was evaluated and applied in quantitative deconvolution of multicomponent spectra. Free acetate concentrations were obtained by the use of geochemical and probabilistic modelling codes. A total of 51 UV-Vis spectra were collected in a wide range of experimental conditions where coordination of U(VI) by acetate ion was indicated by characteristic variations in the spectra structure as compared to UO2 (2+). Using chemometric data analysis, the resulting factor structure was evaluated to obtain a subset of 14 spectra holding only one coordinated species next to UO2 (2+) (aq). The molar absorption coefficient for the U(VI) monoaceto species was estimated as ε 418 = 17.8 ± 1 dm(3) mol(-1) cm(-1). Spectral deconvolution was used to obtain an estimate of the species concentrations which allowed to calculate for each sample the free acetate concentration, the total U(VI) amount and, eventually, to estimate the formation quotient lg β 11 = 2.8 ± 0.3 of UO2(CH3COO)(+).

No MeSH data available.


Related in: MedlinePlus