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AbstractAbstract
[en] Differential-pulse polarographic determination of molybdenum(VI) coupled with a catalytic homogeneous reaction was carried out in a system containing the molybdenum-ferron complex and an oxidant in acetic-acetate buffer. On addition of the powerful oxidant, the peak current for the reduction of the molybdenum(VI) complex was increased significantly. The calibration graph was linear in the concentration range 1x10-6-1x10-7 M and the detection limit was 9.5 ng ml-1. (author). 20 refs.; 3 figs
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AbstractAbstract
[en] Published in summary form only
Original Title
Determinacao do molibdenio e de outros metais pesados por polarografia de pulso diferencial
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Source
Sao Paulo Univ., SP (Brazil). Inst. de Quimica; 29 p; 1987; p. 25; 4. National Meeting on Analytical Chemistry; Sao Paulo, SP (Brazil); 8-11 Sep 1987
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AbstractAbstract
[en] Published in summary form only
Original Title
Determinacao de niobio por polarografia de pulso diferencial
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Bahia Univ., Salvador, BA (Brazil). Inst. de Quimica; 179 p; 1989; p. 79; 5. Brazilian Meeting on Analytical Chemistry; Salvador, BA (Brazil); 4-6 Sep 1989; Available from the Library of the Comissao Nacional de Energia Nuclear, RJ, Brazil
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Tokoro, R.
Sao Paulo Univ., SP (Brazil). Inst. de Quimica1988
Sao Paulo Univ., SP (Brazil). Inst. de Quimica1988
AbstractAbstract
[en] The present study shows some polarographic behavior of indium (III) in azide media that is close those observed in a thiocyanate solution. The presence of azide ligand decreases the overpotential in the discharge of indium whose catalytic character can be explained by formation of an azide bridge between electrode and indium (III) increasing the speed of electron transfer. The discharge of indium in azide media is diffusion controlled. As the azide concentration is increased the half wave potential displaces in the cathodic direction. This displacement is due to complex formation. The number of electrons, n, involved in the total process was estimates by the reversible polarographic equation to be 2,7. The potentiostatic coulometry of indium in azide/hydrazoic acid buffer showed a catalytic process where the chemistry regeneration was performed by reaction of hydrazoic acid and indium amalgam. The electrochemistry evidence was the constancy of current as the electrolysis proceeded. The chemistry aspect was the presence of ammonium cation in electrolysed solution. The catalytic process with chemistry regeneration and the formation of a bridge by azide could explain the higher value of current in azide media compared to perchlorate solution. (author)
[pt]
O presente trabalho procura mostrar alguns aspectos do comportamento polarografico do indio (III) em meio de azoteto que sao muito semelhantes aos observados em meio de tiocianato. A antecipacao da onda do indio (III) na presenca do anion azoteto constitui carater catalitico cuja explicacao residiria na formacao de ponte de azoteto entre o eletrodo e indio (III) facilitando a transferencia de eletron. O processo que governa a descarga do indio em meio de azoteto e a difusao. O potencial de meia-onda do indio se desloca para regiao catodica com crescentes valores da concentracao de azoteto. Este deslocamento e indicio da formacao de complexos. O numero de eletron total, n, envolvido no processo foi estimado pelo uso da equacao polarografica de onda reversivel, encontrando-se o valor de 2,7. A coulometria potenciostatica mostrou a existencia de processo catalitico na reducao do indio (III) em tampao de azoteto/acido azotidrico, ocorrendo a regeneracao quimica do indio (III) pelo ataque do acido azotidrico ou amalgama formado. A evidencia eletroquimica foi a nao diminuicao da corrente com a eletrolise e o fato quimico foi a constatacao de cation amonio na solucao eletrolisada. A explicacao mais provavel da altura da onda do indio (II) ser maior em meio de azoteto comparativamente ao meio de perclorato de sodio estaria na presenca do fenomeno catalitico de regeneracao quimica e tambem na facilidade de transferencia de eletron atraves da ponte de azoteto. (autor)Original Title
Estudos polarograficos sobre o comportamento do indio (III) em meio aquoso de azoteto de sodio
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1988; 129 p; Tese (Livre Doc.).
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AbstractAbstract
No abstract available
Original Title
Radiopolarography used to study redox properties of 5f elements
Source
Conzett, H.E.; Edelstein, N.M.; Tsang, C.F. (eds.); California Univ., Berkeley (USA). Lawrence Berkeley Lab; p. 336-338; Jul 1975
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Report
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Progress Report
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AbstractAbstract
[en] The reduction of molybdenum (VI) in 2,3-dihydroxypyridine, 2-amino-3-hydroxypyridine, 3-hydroxypyridine-2-thiol has been investigated (μ=0.1, supporting electrolyte-sodium perchlorate). Diffusion controlled irreversible cathodic waves are obtained. The values of kinetic parameters, αn and Ksub(f,h)sup(0) have been determined by applying the method of Oldham and Parry. (author)
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9 refs.
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Journal Article
Journal
Fert. Technol; v. 13(2-3); p. 147-149
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Ruf, H.; Friedrich, M.
Kernforschungszentrum Karlsruhe G.m.b.H. (Germany, F.R.). Inst. fuer Radiochemie; Kernforschungszentrum Karlsruhe G.m.b.H. (Germany, F.R.). Projekt Wiederaufarbeitung und Abfallbehandlung1983
Kernforschungszentrum Karlsruhe G.m.b.H. (Germany, F.R.). Inst. fuer Radiochemie; Kernforschungszentrum Karlsruhe G.m.b.H. (Germany, F.R.). Projekt Wiederaufarbeitung und Abfallbehandlung1983
AbstractAbstract
[en] The polarographic behavior of tri-n-butylphosphate (TBP) in nitric acid media in general and its influence on the height of the polarographic wave of uranium in particular are discussed. After the presentation of a short review of the literature concerning this subject, results of own investigations in this field are presented. Trials undertaken with the aim of indirect polarographic determinations of TBP by means of its diminishing effect on the polarographic wave of uranium were without success, which, in view of known facts, is not surprising. (orig.)
[de]
Es werden das polarographische Verhalten von Tri-n-butyl-phosphat (TBP) in salpetersauren Loesungen im allgemeinen, und seine Wirkung auf die polarographische Stufenhoehe des Urans im besonderen betrachtet. Nach einer kurzen Wiedergabe der diesbezueglichen Literaturberichte werden Ergebnisse eigener Untersuchungen zu diesem Thema vorgestellt. Versuche der indirekten polarographischen Bestimmung von TBP ueber seine die polarographische Stufenhoehe des Urans verringernde Wirkung brachten keinen Erfolg, was in Anbetracht bekannter Gegebenheiten nicht ueberrascht. (orig.)Original Title
Zur Frage der Moeglichkeit polarographischer TBP-Bestimmungen
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Dec 1983; 18 p; PWA--78/83
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Report
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Tokoro, R.; Bertotti, M.
Sao Paulo Univ., SP (Brazil). Inst. de Quimica1988
Sao Paulo Univ., SP (Brazil). Inst. de Quimica1988
AbstractAbstract
[en] The present work is a branch of the main work concerned with the complex formation between several metal cations and azide ligand in aqueous media. The polarographic behavior of indium in azide system showed the tendency of complexation. Using polarographic method to determine the half potential of indium at each analytical concentration afforded experimental data to evaluate the constants. The azide concentrations was modified from 1 m to 100 m , the ionic strength held at 2,0 M with sodium perchlorate, indium concentration 7.892 x 10-4 M, and temperature kept constant at 25,00C. (author)
[pt]
Apresenta-se uma parte do trabalho principal de formacao de complexo entre varios cations metalicos e do ligante azoteto em meio aquoso. O comportamento polarografico do indio no sistema azoteto mostrou a tendencia de complexacao. Dados experimentais foram fornecidos para avaliacao das constantes, usando o metodo, polarografico para determinar o potencial do indio. As concentracoes de azoteto foram modificadas de mM para 100 mM, a forca ionica manteve-se em 2,0M com NaclO4, a concentracao do indio foi de 7,892 x 10-4 M e a temperatura constante a 25,00C. (C.G.C.)Original Title
Estudo polarografico sobre a formacao de complexos entre indio (III) e azoteto de sodio, em meio aquoso
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Source
1988; 8 p; 6. Brazilian Symposium on Electrochemistry and Electroanalytics; Sao Paulo, SP (Brazil); 28-30 Mar 1988
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Saleem, P.H.
Mosul Univ. (Iraq). Dept. of Chemistry; Mosul Univ. (Iraq). Coll. of Science1990
Mosul Univ. (Iraq). Dept. of Chemistry; Mosul Univ. (Iraq). Coll. of Science1990
AbstractAbstract
[en] An introduction to the uses and importance of pyrazole-5-one and -2- pyrazoline derivatives, it also contains a concise review of methods of determination for these derivatives, as well, basis of amplification reactions, spectrophotometer, diazotization and polarography. The second chapter deals with determination of some pyrazole-5- one and -2-pyrazoline derivatives by titrimetric method in combination with amplification procedures.(40 tabs., 8 figs., 103 refs.)
Primary Subject
Source
1990; 125 p; Available from Information Center-Iraqi Atomic Energy Commission, Tuwaitha-Baghdad, P.O.BOX 765, IRAQ; Thesis (M.Sc.).
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AbstractAbstract
No abstract available
Original Title
Determinacao cronocoulometrica do ion uranilo em meio nitrato
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36. Annual Meeting of the Brazilian Society for the Advancement of Science; Sao Paulo, SP (Brazil); 4-11 Jul 1984; Published in summary form only.
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Ciencia e Cultura. Suplemento; ISSN 0102-2474;
; v. 36(7); p. 418

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