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134 results on '"Korn, Maria Graças A."'

25. Effect of the Losartan Potassium, Metformin Hydrochloride and Simvastatin on in Vitro Bioacessibility of Cu, Fe, Mn and Zn in Oats Flour from Brazil

Author

de Carvalho, Wellington Correia, primary, de Sousa, Thaís Luz, additional, de Jesus, Ana Cláudia Lima, additional, Souza, Laís Araújo, additional, dos Santos, Luana Cardoso, additional, Simões da Silva, Saul Vislei, additional, Santos, Daniele Cristina Muniz Batist, additional, DE FREITAS SANTOS JUNIOR, ANIBAL, additional, and Korn, Maria Graças Andrade, additional

Published
2022
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32. Evaluation of Sample Preparation Procedures for Trace Element Determination in Brazilian Propolis by Inductively Coupled Plasma Optical Emission Spectrometry and Their Discrimination According to Geographic Region

Author

Korn, Maria Graças Andrade, Guida, Mauro Agildo Barbosa, Barbosa, José Tiago Pereira, Torres, Ednildo Andrade, Fernandes, Andréa Pires, Santos, Josué Carinhanha Caldas, Dantas, Kelly das Graças Fernandes, and Nóbrega, Joaquim Araújo

Published
2013
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45. Determination of copper, iron, lead and zinc in gasoline by sequential multi-element flame atomic absorption spectrometry after solid phase extraction

Author

Santos,Denilson S. S, Korn,Maria Graças A, Guida,Mauro A. B, Santos,Gabriel L. dos, Lemos,Valfredo A, and Teixeira,Leonardo S. G

Subjects
gasoline, metal, preconcentration, solid phase extraction, FS-FAAS
Abstract

A procedure was developed for determination of copper, iron, lead and zinc in gasoline. The procedure was based on the preconcentration of metals using a resin modified with 3,4-dihydroxybenzoic acid (XAD-DHB), followed by desorption with an acid eluent. The components in the eluate were then determined by fast sequence flame atomic absorption spectrometry (FS-FAAS). The gasoline samples were prepared as microemulsions by mixing 80 mL of sample with 17 mL of propan-1-ol and 3 mL of a buffer solution (pH 10). The chemical and physical variables influencing the extraction were optimized. The LODs obtained were 2.2 µg L-1 Fe, 3.1 µg L-1 Cu, 2.3 µg L-1 Pb and 2.6 µg L-1 Zn. The RSDs ranged from 5.8 to 9.7% in samples spiked with 0.05 and 0.1 mg L-1 of each metal and recoveries varied from 82 to 99%. The procedure was suitable for determination of the analytes at µg L-1 levels in gasoline samples collected from several gas stations in Salvador, State of Bahia, Brazil. Desenvolveu-se um procedimento para determinação de cobre, ferro, chumbo e zinco em amostras de gasolina. O procedimento foi baseado na pré-concentração dos metais empregando uma resina modificada com o ácido 3,4-dihidroxibenzóico (XAD-DHB), seguida da dessorção com solução ácida. Os analitos no eluato foram determinados por espectrometria de absorção atômica em chama multielementar seqüencial (FS-FAAS). As amostras de gasolina foram preparadas como microemulsões misturando-se 80 mL de amostra com 17 mL de propan-1-ol e 3 mL de solução tampão (pH 10). As variáveis físico-químicas que influenciam no processo de extração foram otimizadas. Os LODs obtidos foram 2,2 µg L-1 para Fe, 3,1 µg L-1 para Cu, 2,3 µg L-1 para Pb, e 2,6 µg L-1 para Zn. Os valores de RSDs das concentrações dos analitos nas amostras enriquecidas com 0,05 e 0,1 mg L-1 de cada metal variaram de 5,8 a 9,7%. As recuperações variaram de 82 a 99%. O método foi aplicado na determinação dos analitos em níveis de µg L-1 em amostras de gasolinas coletadas em postos revendedores de Salvador, BA, Brasil.

Published
2011

46. Trace elements distribution in hawksbill turtle (Eretmochelys imbricata) and green turtle (Chelonia mydas) tissues on the northern coast of Bahia, Brazil

Author

de Macêdo, Gustavo R., primary, B. Tarantino, Taiana, additional, Barbosa, Isa S., additional, Pires, Thaís T., additional, Rostan, Gonzalo, additional, Goldberg, Daphne W., additional, Pinto, Luis Fernando B., additional, Korn, Maria Graças A., additional, and Franke, Carlos Roberto, additional

Published
2015
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47. Biodiesel chain from the lab bench to the industry: an overview with technology assesment, R&D&I opportunities and tasks

Author

Quintella,Cristina M., Teixeira,Leonardo S. G., Korn,Maria Graças A., Costa Neto,Pedro R., Torres,Ednildo A., Castro,Marilu P., and Jesus,Carlos A. C.

Subjects
biofuels production chain, forecasting, technology assessment
Abstract

Contextualized overview of the Biodiesel Production Chain, from the lab bench to the industry, with critical evaluation of state-of-art and technological development through scientific articles and patents, focusing on feedstock, reaction/production, first and second generation processes, specification and quality, transport, storage, co-products (effluents and sub-products), and emissions. Challenges are identified and solutions are proposed based on the Brazilian feedstock, edaphoclimatic conditions, process monitoring in remote regions, state policy, and environment preservation, among others. Forecasts are made based on the technology assessment, identifying future trends and opportunities for R&D&I.

Published
2009

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