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Registro Completo |
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Biblioteca(s): |
Embrapa Instrumentação. |
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Data corrente: |
28/04/2003 |
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Data da última atualização: |
28/04/2003 |
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Autoria: |
NOVOTNY, E. H.; MARTIN-NETO, L. |
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Afiliação: |
Embrapa Instrumentação Agropecuária, São Carlos, SP. |
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Título: |
Effects of humidity and metal ions on the free radicals analysis of peat humus. |
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Ano de publicação: |
2002 |
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Fonte/Imprenta: |
Geoderma, Amsterdam, v. 106, p. 305-317, 2002. |
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Idioma: |
Inglês |
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Conteúdo: |
The effects of humidity and metal ions in the determination of humic organic free radicals concentration (HOFRC) were studied by electron paramagnetic resonance (EPR). Increasing the sample humidity caused a decrease in both HOFRC, probably due to free radicals recombination, and in the derivative peak-to-peak line width, probably due to a higher spin-spin relaxation time (T2) as the molecular mobility increasd (shorter correlation time). Diamagnetic ions did not affect the HOFRC, while paramagnetic ions induced an intense HOFRC decrease. This effect was associated with dipolar-relaxation enhancement at high (above 0, 01%) paramagnetic ion concentrations, since the inhomogeneity parameter decreased to less than I. Further, a possible exchange interaction an/or shift in the free radicals equilibrium reactions might have occurred at low paramagnetic ion concentrations (below 0,01%. |
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Palavras-Chave: |
Radicais livres; Ressonânica paramagnética; Substâncias húmicas. |
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Thesaurus Nal: |
free radicals; ions. |
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Categoria do assunto: |
-- |
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Marc: |
LEADER 01440naa a2200193 a 4500
001 1024628
005 2003-04-28
008 2002 bl --- 0-- u #d
100 1 $aNOVOTNY, E. H.
245 $aEffects of humidity and metal ions on the free radicals analysis of peat humus.
260 $c2002
520 $aThe effects of humidity and metal ions in the determination of humic organic free radicals concentration (HOFRC) were studied by electron paramagnetic resonance (EPR). Increasing the sample humidity caused a decrease in both HOFRC, probably due to free radicals recombination, and in the derivative peak-to-peak line width, probably due to a higher spin-spin relaxation time (T2) as the molecular mobility increasd (shorter correlation time). Diamagnetic ions did not affect the HOFRC, while paramagnetic ions induced an intense HOFRC decrease. This effect was associated with dipolar-relaxation enhancement at high (above 0, 01%) paramagnetic ion concentrations, since the inhomogeneity parameter decreased to less than I. Further, a possible exchange interaction an/or shift in the free radicals equilibrium reactions might have occurred at low paramagnetic ion concentrations (below 0,01%.
650 $afree radicals
650 $aions
653 $aRadicais livres
653 $aRessonânica paramagnética
653 $aSubstâncias húmicas
700 1 $aMARTIN-NETO, L.
773 $tGeoderma, Amsterdam$gv. 106, p. 305-317, 2002.
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Embrapa Instrumentação (CNPDIA) |
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| 1. |  | GUIMARÃES, I. A. dos S.; BONISSONI, C.; DORS, G. C.; FEDDERN, V.; CUNHA JUNIOR, A.; FELTES, M. M. C.; GONZALES, S. L.; DALLA ROSA, A. Estudo da produção enzimática de biodiesel a partir de óleo de frango em ultrassom. In: MOSTRA NACIONAL DE INICIAÇÃO CIENTÍFICA E TECNOLÓGICA INTERDISCIPLINAR, 8, 2015, Concórdia. Anais... Concórdia: IFC ? Campus Concórdia, 2015.| Tipo: Artigo em Anais de Congresso |
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