Determinação de cálcio e de magnésio em plantas, por fotometria de chama de absorção

Determination of calcium and magnesium in plant material, by absorption flame photometry

Resumos

As concentrações de cálcio e magnésio em extratos de plantas podem ser determinadas por fotometria de chama de absorção com a precisão e exatidão requeridas, mediante a adição de lantânio na concentração de 0,1 %,como agente protetor. Para obtenção dos dados utilizou-se um espectrofotômetro Perkin-Elmer, modelo 303, equipado com sistema digital de leitura.


A method for determination of calcium and magnesium by absorption flame photometry was studied using a Perkin-Elmer model 303 spectrophotometer equiped with digital concentration readout model DCR1. The study of interferents was carried out with concentration usually present in plant material or even in higher concentrations to get information about the possibility of applying this method to other materials. Within the limits of concentration studied, it was observed that calcium determination was affected by the ions Fe 3+, Al3+ , Mn 2+, Si 4+, PO3-4 and SO2-4 . The ions Mg2+ , K+ , Na+ , Cu2+ , Zn2+ , CI- , NO-3 and ClO-4 had no interference. Magnesium determination was affected only by the presence of the ions Al3+ and Si4+. The use of 0.1% lanthanum solution suppressed the interference of 10 ppm of Al3+, Fe3+ or Mn2+, 50 ppm of Si4+ and 100 ppm of PO3-4 or SO2-4 on a 5 ppm calcium solution. It suppressed also the effect of 10 ppm of Al or 50 ppm of Si in the absorbance of 1 ppm magnesium solution. In the application of the method for calcium and magnesium in plant analysis, 0.200 g of dried plant material was digested with 1 ml of nitric acid and 0.5 ml percloric acid. The volume was completed to 50 ml with distilled water. A portion (2 to 10 ml) was transfered to a 50 ml volumetric flask, lanthanum was added to a final concentration of 0.1% and the volume was taken to 50 ml. Calcium and magnesium in plant material were determined using calibration curves, obtained with calcium solutions varying from 0 to 10 ppm and magnesium solutions varying from 0 to 2 ppm (both had 0.1% lanthanum). The method here described yields good accuracy and precision, and seems to be suitable for routine analysis of plant material.


Determinação de cálcio e de magnésio em plantas, por fotometria de chama de absorção1 1 Trabalho subvencionado pelo Acordo Instituto Agronômico — Banco Nacional de Desenvolvimento Econômico, Projeto 19 — Contrato FUNDEPRO 42.

Determination of calcium and magnesium in plant material, by absorption flame photometry

Ondino Cleante Bataglia2 2 Com bolsa de suplementaçao do CNPq. ; J. Romano Gallo2 2 Com bolsa de suplementaçao do CNPq.

Engenheiros-agrônomos, Seção de Química Analítica, Instituto Agronômico

SINOPSE

As concentrações de cálcio e magnésio em extratos de plantas podem ser determinadas por fotometria de chama de absorção com a precisão e exatidão requeridas, mediante a adição de lantânio na concentração de 0,1 %,como agente protetor.

Para obtenção dos dados utilizou-se um espectrofotômetro Perkin-Elmer, modelo 303, equipado com sistema digital de leitura.

SUMMARY

A method for determination of calcium and magnesium by absorption flame photometry was studied using a Perkin-Elmer model 303 spectrophotometer equiped with digital concentration readout model DCR1.

The study of interferents was carried out with concentration usually present in plant material or even in higher concentrations to get information about the possibility of applying this method to other materials.

Within the limits of concentration studied, it was observed that calcium determination was affected by the ions Fe 3+, Al3+ , Mn 2+, Si 4+, PO3-4 and SO2-4 . The ions Mg2+ , K+ , Na+ , Cu2+ , Zn2+ , CI- , NO-3 and ClO-4 had no interference. Magnesium determination was affected only by the presence of the ions Al3+ and Si4+.

The use of 0.1% lanthanum solution suppressed the interference of 10 ppm of Al3+, Fe3+ or Mn2+, 50 ppm of Si4+ and 100 ppm of PO3-4 or SO2-4 on a 5 ppm calcium solution. It suppressed also the effect of 10 ppm of Al or 50 ppm of Si in the absorbance of 1 ppm magnesium solution.

In the application of the method for calcium and magnesium in plant analysis, 0.200 g of dried plant material was digested with 1 ml of nitric acid and 0.5 ml percloric acid. The volume was completed to 50 ml with distilled water. A portion (2 to 10 ml) was transfered to a 50 ml volumetric flask, lanthanum was added to a final concentration of 0.1% and the volume was taken to 50 ml. Calcium and magnesium in plant material were determined using calibration curves, obtained with calcium solutions varying from 0 to 10 ppm and magnesium solutions varying from 0 to 2 ppm (both had 0.1% lanthanum).

The method here described yields good accuracy and precision, and seems to be suitable for routine analysis of plant material.

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LITERATURA CITADA

Recebido para publicação em 19 de agosto de 1971.

  • 1. BERGAMIN FILHO, H. O método colorimétrico do tiazol amarelo na determinaçăo do magnésio. Piracicaba, Esc. Sup. Agric. "Luiz de Queiroz", 1961. 56p. (Tese) (Mimeografado)
  • 2. BERRY, W. L. & JOHNSON, C. M. Determination of calcium and magnesium in plant material and culture solutions, using atomic absorption spectroscopy. Appl. Spectroscopy 20:209-211, 1966.
  • 3. DAVID, D. J. Atomic absorption analysis of plant materials with particular reference to manganese and iron. Atomic Absorption Newsletter, 1962. 6p. (N.° 9)
  • 4. _________. Determination of calcium in plant material by atomic absorption spectrophotometry. Analyst 84:536-545, 1959.
  • 5. _________. Determination of zinc and other elements in plants by atomic absorption spectroscopy. Analyst 83:655-661, 1958.
  • 6. DICKSON, R. E. & JOHNSON, C. M. Interferences associated with the determination of calcium by atomic absorption. Appl. Spectroscopy 20:214-218, 1966.
  • 7. GLORIA, N. A., CATANI, R. A. & MATUO, T. Determinaçăo de cálcio e magnésio em plantas, pelo método do EDTA. An. Esc. Agric. Queiroz 22:154-171, 1965.
  • 8. LOTT, W. L.; McCLUNG, A. C; VITA, R., & GALLO, J. R. Levantamento de cafezais em Săo Paulo e Paraná pela análise foliar. Săo Paulo, Instituto de Pesquisas IRI, 1961. 69p. (Boletim 26)
  • 9. _________; NERY, J. P.; GALLO, J. R. & MEDCALF, J. C. A técnica de análise foliar aplicada ao cafeeiro. Campinas, Instituto Agronômico, 1956. 29p. (Boletim 79)
  • 10. PERKIN-ELMER. Analytical methods for atomic absorption spectrophotometry. Norwalk, Connecticut, 1968.
  • 11. SLAVIN, W. Atomic absorption spectroscopy. New York, Interscience, 1968. 307p.

  • 1
    Trabalho subvencionado pelo Acordo Instituto Agronômico — Banco Nacional de Desenvolvimento Econômico, Projeto 19 — Contrato FUNDEPRO 42.
  • 2
    Com bolsa de suplementaçao do CNPq.

Datas de Publicação

  • Publicação nesta coleção
    17 Mar 2009
  • Data do Fascículo
    1972

Histórico

  • Recebido
    19 Ago 1971
Instituto Agronômico de Campinas Avenida Barão de Itapura, 1481, 13020-902 Campinas SP - Brazil, Tel.: +55 19 2137-0653, Fax: +55 19 2137-0666 - Campinas - SP - Brazil
E-mail: bragantia@iac.sp.gov.br