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 | Acesso ao texto completo restrito à biblioteca da Embrapa Pecuária Sudeste. Para informações adicionais entre em contato com cppse.biblioteca@embrapa.br. |
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Registro Completo |
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Biblioteca(s): |
Embrapa Pecuária Sudeste. |
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Data corrente: |
28/08/2000 |
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Data da última atualização: |
04/01/2022 |
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Tipo da produção científica: |
Artigo em Periódico Indexado |
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Autoria: |
SILVA, F. V.; NOGUEIRA, A. R. de A.; SOUZA, G. B. de; REIS, B. F.; ARAÚJO, A. N.; MONTENEGRO, M. C. M. B. S.; LIMA, J. L. F. C. |
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Afiliação: |
FERNANDO V. SILVA, INSTITUTO DE QUÍMICA DE SÃO CARLOS; ANA RITA DE ARAUJO NOGUEIRA, CPPSE; GILBERTO BATISTA DE SOUZA, CPPSE; BOAVENTURA F. REIS, CENTRO DE ENERGIA NUCLEAR NA AGRICULTURA; ALBERTO N. ARAÚJO, CEQUP; MARIA C. M. B. S. MONTENEGRO, CEQUP; JOSÉ L. F. C. LIMA, CEQUP. |
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Título: |
Potentiometric determination of urea by sequential injection using Jack bean meal crude extract as a source of urease. |
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Ano de publicação: |
2000 |
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Fonte/Imprenta: |
Talanta, v.53, p.331-336, 2000. |
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Idioma: |
Português |
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Conteúdo: |
A sequential injection system was proposed to accomplish the potentiometric determination of urea. This procedure used an ammonium tubular selective electrode to assess ammonium concentration produced by enzymatic hydrolysis of urea from Jack bean meal (Canar;alia ensiformis DC) crude extract. A gaseous diffusion device was coupled to the flow set-up allowing on-line sampling and suitable selectivity for determinations. A detection limit of 6.0 x 10 mol urea 1 ', a relative standard deviation of' 1.9% (n = 10) and a sampling rate of 20 samples h-1 ' were observed when 172 Sumner units (SU) of urease and 900 ul of sample were used. Results agreeing with a comparative method were obtained by the proposed procedure and the use of the crude extract solution combined with the sequential injection approach improved the performance, producing reproducible results and low costs in comparison with procedures using commercial enzymes. |
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Palavras-Chave: |
Ammonium tubular; Crude extract; Selective electrode; SIA. |
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Thesaurus Nal: |
urea. |
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Categoria do assunto: |
W Química e Física |
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Marc: |
LEADER 01679naa a2200253 a 4500
001 1045118
005 2022-01-04
008 2000 bl uuuu u00u1 u #d
100 1 $aSILVA, F. V.
245 $aPotentiometric determination of urea by sequential injection using Jack bean meal crude extract as a source of urease.$h[electronic resource]
260 $c2000
520 $aA sequential injection system was proposed to accomplish the potentiometric determination of urea. This procedure used an ammonium tubular selective electrode to assess ammonium concentration produced by enzymatic hydrolysis of urea from Jack bean meal (Canar;alia ensiformis DC) crude extract. A gaseous diffusion device was coupled to the flow set-up allowing on-line sampling and suitable selectivity for determinations. A detection limit of 6.0 x 10 mol urea 1 ', a relative standard deviation of' 1.9% (n = 10) and a sampling rate of 20 samples h-1 ' were observed when 172 Sumner units (SU) of urease and 900 ul of sample were used. Results agreeing with a comparative method were obtained by the proposed procedure and the use of the crude extract solution combined with the sequential injection approach improved the performance, producing reproducible results and low costs in comparison with procedures using commercial enzymes.
650 $aurea
653 $aAmmonium tubular
653 $aCrude extract
653 $aSelective electrode
653 $aSIA
700 1 $aNOGUEIRA, A. R. de A.
700 1 $aSOUZA, G. B. de
700 1 $aREIS, B. F.
700 1 $aARAÚJO, A. N.
700 1 $aMONTENEGRO, M. C. M. B. S.
700 1 $aLIMA, J. L. F. C.
773 $tTalanta$gv.53, p.331-336, 2000.
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Registro original: |
Embrapa Pecuária Sudeste (CPPSE) |
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| Acesso ao texto completo restrito à biblioteca da Embrapa Meio Ambiente. Para informações adicionais entre em contato com cnpma.biblioteca@embrapa.br. |
Registro Completo
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Biblioteca(s): |
Embrapa Meio Ambiente. |
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Data corrente: |
07/06/1993 |
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Data da última atualização: |
09/08/2021 |
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Tipo da produção científica: |
Artigo em Periódico Indexado |
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Autoria: |
JONSSON, C. M.; TOLEDO, M. C. F. |
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Afiliação: |
CLAUDIO MARTIN JONSSON, CNPMA; MARIA CECILIA F. TOLEDO, UNIVERSIDADE ESTADUAL DE CAMPINAS. |
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Título: |
Acute toxicity of endosulfan to the fish Hyphessobrycon bifasciatus and Brachydanio rerio. |
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Ano de publicação: |
1993 |
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Fonte/Imprenta: |
Archives of Environmental Contamination and Toxicology, v.24, p.151-155, 1993. |
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Páginas: |
151-155 p. |
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Idioma: |
Inglês |
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Conteúdo: |
Acute toxicity of endosulfan to zebra fish (Brachydanio rerio) and yellow tetra (Hyphessobrycon bifasciatus) was determined by semi-static bioassay. The 24-h LC50 values were 2.6 (2.3-2.9) and 1.6 (1.3-21) ug/L for Hyphessobrycon bifasciatus and Brachydanio rerio, respectively. Behavioral changes including hyperactivity, erratic swimming and convulsions were observed at the highest exposure levels. Histological studies showed predominant acute effects in the gills, with inflammatory infiltration necrosis and separation of respiratory gill epithelim. Degradation studies with endosulfan showed that both alfa- and beta/isomers were very unstable under the test conditions, presenting half-lives of aproximately 24h. |
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Palavras-Chave: |
Brachydanio rerio; Contamination; Insecticide; Pesticide; Residues. |
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Thesagro: |
Endosulfan. |
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Thesaurus NAL: |
fish; Hyphessobrycon bifasciatus; toxicology. |
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Categoria do assunto: |
-- |
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Marc: |
LEADER 01457naa a2200253 a 4500
001 1010518
005 2021-08-09
008 1993 bl uuuu u00u1 u #d
100 1 $aJONSSON, C. M.
245 $aAcute toxicity of endosulfan to the fish Hyphessobrycon bifasciatus and Brachydanio rerio.$h[electronic resource]
260 $c1993
300 $a151-155 p.
520 $aAcute toxicity of endosulfan to zebra fish (Brachydanio rerio) and yellow tetra (Hyphessobrycon bifasciatus) was determined by semi-static bioassay. The 24-h LC50 values were 2.6 (2.3-2.9) and 1.6 (1.3-21) ug/L for Hyphessobrycon bifasciatus and Brachydanio rerio, respectively. Behavioral changes including hyperactivity, erratic swimming and convulsions were observed at the highest exposure levels. Histological studies showed predominant acute effects in the gills, with inflammatory infiltration necrosis and separation of respiratory gill epithelim. Degradation studies with endosulfan showed that both alfa- and beta/isomers were very unstable under the test conditions, presenting half-lives of aproximately 24h.
650 $afish
650 $aHyphessobrycon bifasciatus
650 $atoxicology
650 $aEndosulfan
653 $aBrachydanio rerio
653 $aContamination
653 $aInsecticide
653 $aPesticide
653 $aResidues
700 1 $aTOLEDO, M. C. F.
773 $tArchives of Environmental Contamination and Toxicology$gv.24, p.151-155, 1993.
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