Estudos sobre a nutrição mineral do sorgo sacarino (Sorghum bicolor (L) Moench) cv. Brands. II: absorção e redistribuição do radiofósforo

This paper deals with the following aspects of the phosphatic nutrition of sweet sorghum: absorption of radiophosphate as influenced by time of uptake and external concentration; comparative foliar absorption of monoammonium and diammonium phosphate both in the presence and absence of urea; redistribution of previously absorbed and stored phosphate. Data obtained herewith allowed for the following conclusions to be drawn: (1) root absorption increased with time of contact, being higher in the case of excised when compared to roots in intact plants; (2) Michaelis and Menten kinetics are applicable to root uptake, the parameters being different for the two types of root material; (3) the two ammonium phosphates showed the same rate of uptake, which was not influenced by urea; (4) P deficient plants showed highes rates of uptake and translocation.Foi estudada a absorção radicular do radiofósforo sob influência do tempo de contato com a solução e da concentração externa. Foi também estudada a absorção foliar dos fosfatos mono e diamônico isolados e em presença de uréia. A redistribuiçao do P absorvido pelas raízes foi acompanhada através do fracionamento das formas de fósforo nos diversos órgaos da planta analisadas em diferentes períodos

Statistical Design-principal Component Analysis Optimization Of A Multiple Response Procedure Using Cloud Point Extraction And Simultaneous Determination Of Metals By Icp Oes

A procedure has been developed for the simultaneous determination of traces amounts of Cd, Cr, Cu, Mn, Ni and Pb from saline oil-refinery effluents and digested vegetable samples using inductively coupled plasma optical emission spectrometry (ICP OES). The procedure is based on cloud point extraction (CPE) of these metals as 2-(bromo-2-pyridylazo)-5-diethyl-amino-phenol (Br-PADAP) complexes into a micellar phase of octylphenoxypolyethoxyethanol (Triton X-114). Optimization of the procedure was performed by response surface methodology (RSM) using a Doehlert design. Principal components (PC) were used to simplify the multiple response analysis. A response surface for the first PC score is useful in determining the optimum conditions for the Cd, Cr, Cu, Mn and Pb determinations whereas the second PC is highly correlated with the Ni response. Improvement factors of 22, 36, 46, 25, 65 and 39, along with limits of detection (3σB) of 0.081, 0.79, 0.38, 0.83, 0.28 and 0.69 μg L-1, and precision expressed as relative standard deviation (%R.S.D., n = 8, 20.0 μg L-1) of 1.5, 2.2, 3.5, 2.6, 2.5 and 2.5 were achieved for Cd, Cr, Cu, Mn, Ni and Pb, respectively. The accuracy was evaluated by spike tests in oil-refinery effluent samples and analysis of a vegetable certified reference material (NIST 1571, orchard leaves). Results found were in agreement with certified values. © 2006 Elsevier B.V. All rights reserved.5802251257Bezerra, M.A., Arruda, M.A.Z., Ferreira, S.L.C., (2005) Appl. Spectrosc. Rev., 40, p. 269Hinze, W.L., Pramauro, E., (1993) Crit. Rev. Anal. Chem., 24, p. 133Ferreira, H.S., Bezerra, M.A., Ferreira, S.L.C., (2006) Mikrochim. Acta, 154, p. 163Lemos, V.A., Santos, J.S., Baliza, P.X., (2006) J. Braz. Chem. Soc., 17, p. 30Giokas, D.L., Paleologos, E.K., Veltsistas, P.G., Karayannis, M.I., (2002) Talanta, 56, p. 415Manzoori, J.L., Bavili-Tabrizi, A., (2003) Mikrochim. Acta, 141, p. 201Paleologos, E.K., Giokas, D.L., Tzouara-Karayanni, S.M., (2002) Anal. Chim. Acta, 458, p. 241Manzoori, J.L., Karim-Nezhad, G., (2003) Anal. Chim. Acta, 484, p. 155Cheng, J., Teo, K.C., (2001) Anal. Chim. Acta, 450, p. 215Fan, Z.F., (2005) Mikrochim. Acta, 152, p. 29Bezerra, M.A., Conceição, A.L.B., Ferreira, S.L.C., (2006) Mikrochim. Acta, 154, p. 149Silva, M.A.M., Frescura, V.L.A., Curtius, A.J., (2000) Spectrochim. Acta B, 55, p. 803Silva, M.A.M., Frescura, V.L.A., Curtius, A.J., (2001) Spectrochim. Acta B, 56, p. 1941Borges, D.L.G., Veiga, M.A.M.S., Frescura, V.A.L., Welz, B., Curtius, A.J., (2003) J. Anal. Atom. Spectrom., 18, p. 501Zhu, X., Zhu, X., Wang, B., (2006) Mikrochim. Acta, 154, p. 95Shemirani, F., Baghdadi, M., Ramezani, M., Jamali, M.R., (2005) Anal. Chim. Acta, 534, p. 163Maranhão, T.A., Borges, D.L.G., Veiga, M.A.M.L., Curtius, A.J., (2005) Spectrochim. Acta B, 60, p. 667Wuillound, G.M., Wuillound, J.C.A., Wuillound, R.G., Silva, M.F., Olsina, R.A., Martinez, L.D., (2002) Talanta, 58, p. 619Sombra, L.L., Luconi, M.O., Fernandez, L.P., Olsina, R.A., Silva, M.F., Martinez, L.D., (2003) J. Pharm. Biomed. Anal., 30, p. 1451Wuillound, J.C.A., Wuillound, R.G., Silva, M.F., Olsima, R.A., Martinez, L.D., (2002) Spectrochim. Acta B, 57, p. 365Li, J., Liang, P., Shi, T.Q., Lu, H.B., (2003) Atom. Spect., 24, p. 169Luconi, M.O., Silva, M.F., Olsina, R.A., Fernandez, L.P., (2000) Talanta, 51, p. 123Bruns, R.E., Scarminio, I.S., de Barros Neto, B., (2006) Statistical Design-Chemometrics, , Elsevier, AmsterdamDerringer, G., Suich, R., (1980) J. Qual. Technol., 12, p. 214Carro, A.M., Lorenzo, R.A., (2001) Analyst, 126, p. 1005Scarminio, I.S., Audrey, A.S.G., Lucas, L.M.C., Ferreira, D.T., (2005) Anal. Sci., 21, p. 235Wold, S., Albano, C., Dunn III, W.J., Edlund, U., Esbensen, K., Geladi, P., Hellberg, S., Sjöström, M., (1984) Chemometrics, Mathematics and Statistics in Chemistry, , Kowalski B.R. (Ed), Reidel, DordrechtNieuwoudt, H.H., Prior, B.A., Pretorius, I.S., Manley, M., Bauer, F.F., (2004) J. Agric. Food Chem., 52, p. 3726Ferreira, S.L.C., dos Santos, W.N.L., Quintella, C.M., Neto, B.B., Bosque-Sendra, J.M., (2004) Talanta, 63, p. 106

A pre-concentration procedure using coprecipitation for determination of lead and iron in several samples using flame atomic absorption spectrometry

The present paper proposes a pre-concentration procedure for determination of lead and iron in several samples by flame atomic absorption spectrometry. In it, lead(II) and iron(III) ions are coprecipitated using the violuric acid-copper(II) system as collector. Afterwards, the precipitate is dissolved with 1 M HNO3 solution and the metal ions are determined. The optimization step was performed using factorial design involving the variables: pH, violuric acid mass (VA) and copper concentration (Cu). Using the optimized experimental conditions, the proposed procedure allows the determination these metals with detection limits of 0.18 μg L-1 for iron and 0.16 μg L-1 for lead. The effects of foreign ions on the pre-concentration procedure were also evaluated and the results demonstrated that this method could be applied for determination of iron and lead in several real samples. The proposed method was successfully applied to the analysis of seawater, urine, mineral water, soil and physiological solution samples. The concentrations of lead and iron achieved in these samples agree well with others data reported in the literature. © 2006 Elsevier B.V. All rights reserved

Sixteenth Brazilian Meeting On Analytical Chemistry (brazil, 2011)

[No abstract available]1091

19th Brazilian meeting on analytical chemistry

sem informação15