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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: |
13/05/2003 |
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Data da última atualização: |
09/06/2022 |
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Tipo da produção científica: |
Artigo em Periódico Indexado |
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Autoria: |
ARAÚJO, G. C. L.; GONZALEZ, M. H.; FERREIRA, A. G.; NOGUEIRA, A. R. de A.; NÓBREGA, J. A. |
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Afiliação: |
GEÓRGIA C. L. ARAÚJO, UFSCAR; MÁRIO H. GONZALEZ, UFSCAR; ANTÔNIO G. FERREIRA, UFSCAR; ANA RITA DE ARAUJO NOGUEIRA, CPPSE; JOAQUIM A. NÓBREGA, UFSCAR. |
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Título: |
Effect of acid concentration on closed-vessel microwave-assisted digestion of plant materials. |
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Ano de publicação: |
2002 |
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Fonte/Imprenta: |
Spectrochimica Acta part B, v.57, n.12, p.2121-2132, 2002. |
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DOI: |
https://doi.org/10.1016/S0584-8547(02)00164-7 |
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Idioma: |
Inglês |
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Conteúdo: |
The efficiency of microwave-assisted acid digestion of plants using different concentrations of nitric acid (2.0, 3.0, 5.0, 7.0 and 14 mol l-1) with hydrogen peroxide (30% v/v) was evaluated by measuring the residual carbon content (RCC) using inductively coupled plasma optical emission spectrometry (ICP-OES) with axial viewing. Certified reference materials were used for evaluating the accuracy attained when 2 mol l-1 HNO3 was employed for digestion. Under all experimental conditions RCC values were always lower than 13% w/v, and even the highest concentration did not cause any interference with element recovery. It seems that the high pressure reached for closed-vessel operation improved the oxidative action of nitric acid due to consequent temperature increase, even when this reagent was not used at high concentrations. According to acid?base titration data, residual acid in the digestates varied from 1.2 to 4.0 mol l-1, depending on the acid concentration initially added. It can be concluded that for plant materials, microwave-assisted acid digestion can be carried out under mild conditions, which implies that digestates do not need extensive dilution before introduction by pneumatic nebulization to ICP-OES. An additional advantage is the lower amount of residue generated when working with less concentrated acid solutions. |
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Palavras-Chave: |
Acid digestion; Closed vessel; Inductively coupled plasma optical emission spectrometry (ICP-OES; Microwave-assisted digestion; Plant materials; Residual carbon content. |
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Categoria do assunto: |
W Química e Física |
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Marc: |
LEADER 02212naa a2200253 a 4500
001 1046355
005 2022-06-09
008 2002 bl uuuu u00u1 u #d
024 7 $ahttps://doi.org/10.1016/S0584-8547(02)00164-7$2DOI
100 1 $aARAÚJO, G. C. L.
245 $aEffect of acid concentration on closed-vessel microwave-assisted digestion of plant materials.$h[electronic resource]
260 $c2002
520 $aThe efficiency of microwave-assisted acid digestion of plants using different concentrations of nitric acid (2.0, 3.0, 5.0, 7.0 and 14 mol l-1) with hydrogen peroxide (30% v/v) was evaluated by measuring the residual carbon content (RCC) using inductively coupled plasma optical emission spectrometry (ICP-OES) with axial viewing. Certified reference materials were used for evaluating the accuracy attained when 2 mol l-1 HNO3 was employed for digestion. Under all experimental conditions RCC values were always lower than 13% w/v, and even the highest concentration did not cause any interference with element recovery. It seems that the high pressure reached for closed-vessel operation improved the oxidative action of nitric acid due to consequent temperature increase, even when this reagent was not used at high concentrations. According to acid?base titration data, residual acid in the digestates varied from 1.2 to 4.0 mol l-1, depending on the acid concentration initially added. It can be concluded that for plant materials, microwave-assisted acid digestion can be carried out under mild conditions, which implies that digestates do not need extensive dilution before introduction by pneumatic nebulization to ICP-OES. An additional advantage is the lower amount of residue generated when working with less concentrated acid solutions.
653 $aAcid digestion
653 $aClosed vessel
653 $aInductively coupled plasma optical emission spectrometry (ICP-OES
653 $aMicrowave-assisted digestion
653 $aPlant materials
653 $aResidual carbon content
700 1 $aGONZALEZ, M. H.
700 1 $aFERREIRA, A. G.
700 1 $aNOGUEIRA, A. R. de A.
700 1 $aNÓBREGA, J. A.
773 $tSpectrochimica Acta part B$gv.57, n.12, p.2121-2132, 2002.
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Registro original: |
Embrapa Pecuária Sudeste (CPPSE) |
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Biblioteca |
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Origem |
Tipo/Formato |
Classificação |
Cutter |
Registro |
Volume |
Status |
URL |
Voltar
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Registro Completo
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Biblioteca(s): |
Embrapa Agroindústria Tropical; Embrapa Caprinos e Ovinos. |
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Data corrente: |
09/01/2020 |
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Data da última atualização: |
14/12/2020 |
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Tipo da produção científica: |
Artigo em Periódico Indexado |
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Circulação/Nível: |
A - 2 |
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Autoria: |
LOPES, M. N.; CÂNDIDO, M. J. D.; POMPEU, R. C. F. F.; SILVA, R. G. da; LACERDA, C. F. de; BEZERRA, M. A.; MORAIS NETO, L. B. de; CARNEIRO, M. S. de S. |
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Afiliação: |
MARCOS NEVES LOPES; MAGNO JOSÉ DUARTE CÂNDIDO; ROBERTO CLAUDIO FERNANDES F POMPEU, CNPC; RODRIGO GREGÓRIO DA SILVA; CLAUDIVAN FEITOSA DE LACERDA; MARLOS ALVES BEZERRA, CNPAT; LUIZ BARRETO DE MORAIS NETO; MARIA SOCORRO DE SOUZA CARNEIRO. |
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Título: |
Gas exchange in Massai grass fertilized with nitrogen and grazed by sheep. |
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Ano de publicação: |
2020 |
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Fonte/Imprenta: |
Bioscience Journal, v. 36, n. 1, p. 152-160, Jan./Feb. 2020. |
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DOI: |
http://dx.doi.org/10.14393/BJ-v36n1a2020-42411 |
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Idioma: |
Inglês
Português |
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Conteúdo: |
The knowledge of gas exchanges in forage plants is essential for a better understanding of the process of forage biomass production in pasture. This study evaluated the gas exchange in massai grass fertilized with increasing levels of nitrogen fertilizer (control - without nitrogen fertilizer; 400; 800 and 1200 kg ha-1 year-1) and under rotational grazing by sheep, in a completely randomized design with repeated measures in time. The rest period was approximately 1.5 new leaves per tiller, as determined in the pre-test at the beginning of the experiment, providing interval of 22; 18; 16 and 13 days for the levels 0.0 - control; 400; 800 and 1200 kg ha-1 year-1 nitrogen, respectively. The animals used to lower the sward height to the recommended residual height were sheep (½ Morada Nova x ½ undefined breed), placed in paddocks of 42.3 m2 . As the animals grazed, the height of the sward was monitored with a ruler until the canopy reached the recommended residual height of approximately 15 cm, corresponding to the residual LAI of exit of the animals from the paddock at approximately 1.5, as determined in a pre-test to set up the experiment. The variables stomatal conductance, leaf photosynthesis rate, leaf carbon dioxide concentration, photosynthesis/transpiration ratio, chlorophyll relative index and nitrogen sufficiency index revealed a positive linear response to nitrogen fertilization. Nitrogen fertilization level at 1200 kg ha-1 year-1 caused an increment of 92.3% in leaf photosynthesis rate in relation to the control. The leaf temperature and photosynthesis/conductance ratio were reduced with increasing nitrogen levels. The leaf transpiration showed a quadratic response with maximum point with increasing nitrogen levels. Nitrogen fertilization favor the gas exchange in massai grass up to the last level tested. [Trocas gasosas em capim-massai adubado com nitrogênio e pastejado por ovinos]. MenosThe knowledge of gas exchanges in forage plants is essential for a better understanding of the process of forage biomass production in pasture. This study evaluated the gas exchange in massai grass fertilized with increasing levels of nitrogen fertilizer (control - without nitrogen fertilizer; 400; 800 and 1200 kg ha-1 year-1) and under rotational grazing by sheep, in a completely randomized design with repeated measures in time. The rest period was approximately 1.5 new leaves per tiller, as determined in the pre-test at the beginning of the experiment, providing interval of 22; 18; 16 and 13 days for the levels 0.0 - control; 400; 800 and 1200 kg ha-1 year-1 nitrogen, respectively. The animals used to lower the sward height to the recommended residual height were sheep (½ Morada Nova x ½ undefined breed), placed in paddocks of 42.3 m2 . As the animals grazed, the height of the sward was monitored with a ruler until the canopy reached the recommended residual height of approximately 15 cm, corresponding to the residual LAI of exit of the animals from the paddock at approximately 1.5, as determined in a pre-test to set up the experiment. The variables stomatal conductance, leaf photosynthesis rate, leaf carbon dioxide concentration, photosynthesis/transpiration ratio, chlorophyll relative index and nitrogen sufficiency index revealed a positive linear response to nitrogen fertilization. Nitrogen fertilization level at 1200 kg ha-1 year-1 caused an increment of 92.3% in leaf ... Mostrar Tudo |
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Palavras-Chave: |
Brazilian Northeast; Capim Massai; Chlorophyll relative index; Leaf photosynthesis; Nitrogen fertilization. |
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Thesagro: |
Gramínea Forrageira; Panicum Maximum. |
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Thesaurus NAL: |
Biomass production; Forage grasses. |
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Categoria do assunto: |
L Ciência Animal e Produtos de Origem Animal |
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URL: |
https://ainfo.cnptia.embrapa.br/digital/bitstream/item/219165/1/ART20004.pdf
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Marc: |
LEADER 02937naa a2200325 a 4500
001 2122658
005 2020-12-14
008 2020 bl uuuu u00u1 u #d
024 7 $ahttp://dx.doi.org/10.14393/BJ-v36n1a2020-42411$2DOI
100 1 $aLOPES, M. N.
245 $aGas exchange in Massai grass fertilized with nitrogen and grazed by sheep.$h[electronic resource]
260 $c2020
520 $aThe knowledge of gas exchanges in forage plants is essential for a better understanding of the process of forage biomass production in pasture. This study evaluated the gas exchange in massai grass fertilized with increasing levels of nitrogen fertilizer (control - without nitrogen fertilizer; 400; 800 and 1200 kg ha-1 year-1) and under rotational grazing by sheep, in a completely randomized design with repeated measures in time. The rest period was approximately 1.5 new leaves per tiller, as determined in the pre-test at the beginning of the experiment, providing interval of 22; 18; 16 and 13 days for the levels 0.0 - control; 400; 800 and 1200 kg ha-1 year-1 nitrogen, respectively. The animals used to lower the sward height to the recommended residual height were sheep (½ Morada Nova x ½ undefined breed), placed in paddocks of 42.3 m2 . As the animals grazed, the height of the sward was monitored with a ruler until the canopy reached the recommended residual height of approximately 15 cm, corresponding to the residual LAI of exit of the animals from the paddock at approximately 1.5, as determined in a pre-test to set up the experiment. The variables stomatal conductance, leaf photosynthesis rate, leaf carbon dioxide concentration, photosynthesis/transpiration ratio, chlorophyll relative index and nitrogen sufficiency index revealed a positive linear response to nitrogen fertilization. Nitrogen fertilization level at 1200 kg ha-1 year-1 caused an increment of 92.3% in leaf photosynthesis rate in relation to the control. The leaf temperature and photosynthesis/conductance ratio were reduced with increasing nitrogen levels. The leaf transpiration showed a quadratic response with maximum point with increasing nitrogen levels. Nitrogen fertilization favor the gas exchange in massai grass up to the last level tested. [Trocas gasosas em capim-massai adubado com nitrogênio e pastejado por ovinos].
650 $aBiomass production
650 $aForage grasses
650 $aGramínea Forrageira
650 $aPanicum Maximum
653 $aBrazilian Northeast
653 $aCapim Massai
653 $aChlorophyll relative index
653 $aLeaf photosynthesis
653 $aNitrogen fertilization
700 1 $aCÂNDIDO, M. J. D.
700 1 $aPOMPEU, R. C. F. F.
700 1 $aSILVA, R. G. da
700 1 $aLACERDA, C. F. de
700 1 $aBEZERRA, M. A.
700 1 $aMORAIS NETO, L. B. de
700 1 $aCARNEIRO, M. S. de S.
773 $tBioscience Journal$gv. 36, n. 1, p. 152-160, Jan./Feb. 2020.
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Embrapa Agroindústria Tropical (CNPAT) |
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