Navegando por Autor "Queiroz, Maria Eliana Lopes Ribeiro de"
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Item Análise de risco de contaminação de águas superficiais e subterrâneas por pesticidas em municípios do Alto Paranaíba - MG(Química Nova, 2011-04-15) Andrade, André Santana; Queiroz, Vagner Tebaldi de; Lima, Diego Tolentino de; Drumond, Luis César Dias; Queiroz, Maria Eliana Lopes Ribeiro de; Neves, Antônio AugustoA preliminary analyses of the possible contamination of surface and groundwater by the active ingredients of the pesticide products used in the areas with intensive agricultural activities of Alto Paranaíba region, MG, Brazil, was carried out. The active ingredients and formulated products most used in the region were identified and their characteristics of environmental importance were presented. The EPA screening criteria, the groundwater ubiquity score (GUS) and the criteria proposed by Goss were used to evaluate which pesticides might contaminate the local waters. Among the active ingredients studied, several present risks to the local aquatic environment.Item Antioxidant in mango (Mangifera indica L.) pulp(Plant Foods for Human Nutrition, 2007-01-23) Ribeiro, Sônia Machado Rocha; Queiroz, José Humberto; Queiroz, Maria Eliana Lopes Ribeiro de; Campos, Flávia Milagres; Sant’Ana, Helena Maria PinheiroThis work was carried out to investigate the pulp composition of four mango cultivars (Haden, Tommy Atkins and Ubá) at the ripening stage in relation to three components with antioxidant potential (total phenolics, carotenoids and ascorbic acid). Total phenolic compound content was estimated by the Folin-Ciocalteu reagent and total carotenoid content by spectrophotometry at 450 nm. The contents of β-carotene and total vitamin C (ascorbic acid and dehydroascorbic acid) were quantified by high performance liquid chromatography. Differences were found among the four mango cultivars in all the components analyzed. The content of phenolic compounds ranged from 48.40 (Haden) to 208.70 mg/100 g (Ubá); total carotenoid from 1.91 (Haden) to 2.63 mg/100 g (Palmer); β-carotene from 661.27 (Palmer) to 2,220 μg/100 g (Ubá) and total ascorbic acid ranged from 9.79 (Tommy Atkins) to 77.71 mg/100 g (Ubá). These results corroborated previous information that mangoes are a good source of antioxidants in human diet.Item Characterization and evaluation of sorption potential of the iron mine waste after Samarco dam disaster in Doce River basin – Brazil(Chemosphere, 2018-10) Almeida, Cristiane Aparecida; Oliveira, André Fernando de; Pacheco, Anderson Almeida; Lopes, Renata Pereira; Neves, Antônio Augusto; Queiroz, Maria Eliana Lopes Ribeiro deThe Fundão dam collapsed releasing 60 million tons of mining waste into the environment. The mining wastes should be better studied, since some of them are deposited on the alluvial plains soil and at the bottom of the rivers, like sediments, of the region affected. Thus, this work aims to perform the chemical, physical and adsorptive characterization of the samples colleted in region de Paracatu de Baixo. The mining waste has uneven surface, with sizes ranging from 2 to 200 μm, pHPCZ in 6.0. Are composed predominantly by kaolinite, goethite, hematite, gibbsite and quartz. It has been classified as non-hazardous residues. The adsorption studies showed the mining waste have a low Cationic Exchange Capacity. The sorption process was occurs by ion exchange and the kinetics follows the pseudo second order model (R2 > 0.78). The process is endothermic (ΔH in 29.33 kJ mol−1) and spontaneous (ΔG in −24.7 kJ mol−1 at 25 °C). The Langmuir model presented a better fit (R2 > 0.995) to the experimental data. Therefore, the methylene blue can be used as a cation model to predict the behavior of cationic species on the mining waste, with maximum adsorption capacity of 4.42 mg g−1 at 25 °C.Item Degradation kinetics of pirimiphos-methyl residues in maize grains exposed to ozone gas(Elsevier Journal of Stored Products Research, 2017-12) Freitas, Romenique da Silva de; Faroni, Lêda Rita D'Antonino; Queiroz, Maria Eliana Lopes Ribeiro de; Heleno, Fernanda Fernandes; Prates, Lucas Henrique FigueiredoThis work investigates the kinetics of degradation of pirimiphos-methyl residues in maize grains exposed to ozone gas and evaluates the effect of ozonation on grain quality. The assays employed maize grains treated with the insecticide, namely Actellic 500 CE® (pirimiphos-methyl), which were exposed for different periods to ozone gas at a concentration of 0.86 mg L−1, provided at a continuous flow rate of 1.0 L min−1. The insecticide residues were extracted from the grains using solid-liquid extraction with low temperature partitioning. The extracts were analyzed by gas chromatography with electron capture detection. Ozone effectively degraded more than 91% of the pirimiphos-methyl residues, with the degradation efficiency increasing in direct proportion to the duration of exposure to the gas. A first order kinetic model provided the best fit to the degradation data. The use of ozone gas did not alter the qualitative characteristics of the maize.Item Desenvolvimento do método de extração sólido-líquido com partição em baixa temperatura para determinação de inseticidas em grãos de milho ozonizados(Química Nova, 2013-10-04) Freitas, Romenique da Silva de; Queiroz, Maria Eliana Lopes Ribeiro de; Faroni, Lêda Rita D'Antonino; Heleno, Fernanda Fernandes; Moura, Vanessa Vaz deThe objective of this study was to optimize and validate a solid-liquid extraction method with low-temperature partitioning (SLE/LTP) for the analysis of pesticides. This method was coupled with gas chromatography (GC/ECD) and used to evaluate the degradation of bifenthrin and pirimiphos-methyl in maize grains on exposure to ozone. The optimized SLE/LTP-GC/ECD method is simple, effective and consumes low quantities of the solvent. It can be routinely used for the determination of bifenthrin and pirimiphos-methyl in maize samples. The use of this method of analysis determined that the levels of the insecticides in maize grains were reduced on exposure of the grains to the ozone gas. The observed reduction in the levels of insecticide was directly proportional to the increase in the concentration of the ozone gas.Item Determination of Haloxyfop-Methyl, Linuron, and Procymidone pesticides in carrot using SLE-LTP extraction and GC-MS(Food Analytical Methods, 2015-09-23) Lara, Marcelo César Rosa; Araújo, Emiliane Andrade; Reis, Marcelo Rodrigues dos; Viriato, Rodolfo Lázaro Soares; Rocha, Renata Abadia Reis; Gonçalves, Rosembergue Gabriel Lima; Heleno, Fernanda Fernandes; Queiroz, Maria Eliana Lopes Ribeiro de; Tronto, Jairo; Pinto, Frederico GarciaThis study aimed to optimize and validate an analytical method for extraction, detection, and quantification of haloxyfop-methyl, procymidone, and linuron pesticides in carrot samples using solid–liquid extraction methods and low temperature partition (SLE-LTP), accompanied by gas chromatography coupled to mass spectrometry (GC-MS). For SLE-LTP technical optimization, we utilized a complete factorial planning, which had as its variables, agitation time, freezing time, and the correct sample mass/extracting solution volume ratio. The organic extract obtained was analyzed by GC-MS. To test the performance of this procedure, the method was validated and applied to the monitoring of pesticide residues in 20 samples of carrot produced in Alto Paranaíba, Minas Gerais, Brazil. The proposed method showed linearity between 0.5 and 3.5 mg·kg^−1 with correlation coefficients greater than 0.99. The quantification limits were 0.48 mg·kg^−1 for haloxyfop-methyl, 0.69 mg·kg^−1 for linuron, and 0.65 mg·kg^−1 for procymidone, values below the maximum residue limit provided by international legislation of 1.0 mg·kg^−1 for linuron and procymidone. The use of haloxyfop-methyl is not approved in the cultivation of carrot. The recovery percentages were between 90 and 110 %, with a coefficient of variation of less than 12 %. Ten percent of the carrot samples monitored showed residues of linuron and procymidone in concentrations exceeding those permitted by Brazilian law.Item Evaluation of pesticide adsorption in gas chromatographic injector and column(Química Nova, 2012-01-31) Neves, Antônio Augusto; Pinho, Gevany Paulino de; Silvério, Flaviano Oliveira; Queiroz, Maria Eliana Lopes Ribeiro deComponents in complex matrices can cause variations in chromatographic response during analysis of pesticides by gas chromatography. These variations are related to the competition between analytes and matrix components for adsorption sites in the chromatographic system. The capacity of the pesticides chlorpyrifos and deltamethrin to be adsorbed in the injector and chromatographic column was evaluated by constructing three isotherms and changing the column heating rate to 10 and 30 ºC min-1. By using ANCOVA to compare the slope of calibration graphs, results showed that the higher the injector temperature (310 ºC) the lower the pesticide adsorption. Also, deltamethrin influenced the adsorption of chlorpyrifos on the column chromatographic.Item Influência da matéria orgânica na adsorção do fungicida triadimenol pelo solo(Química Nova, 2002-07) Lopes, Nilva Pereira; Queiroz, Maria Eliana Lopes Ribeiro de; Neves, Antônio Augusto; Zambolim, LaércioThe adsorption of triadimenol (1-(4-chlorophenoxy)-3,3-dimethyl-1-(1H-1,2,4-triazol-1-yl)butan-2-ol) on soil samples with varying contents of organic matter was studied. The adsorption was described by means of the Freundlich's isoterm. An increase in the capacity of adsorption was observed as the content of organic carbon in the matrix increased. That effect was observed when removing the organic matter from the soil, when adding a urban waste compost to the soil sample as well as to the soil sample without organic matter, and also after leaving proportions of urban waste compost incubated in these matrices for a period of 120 days. The results show that the adsorption of the triadimenol in the soil is dependent of its content of organic carbon.Item Meia-vida do diuron em solos com diferentes atributos físicos e químicos(Ciência Rural, 2013-06-12) Rocha, Paulo Roberto Ribeiro; Faria, Autieres Teixeira; Silva, Gustavo Soares da; Queiroz, Maria Eliana Lopes Ribeiro de; Guimarães, Franklyn Clawdy Nunes; Tironi, Siumar Pedro; Galon, Leandro; Silva, Antonio Alberto daA distribuição e a dissipação dos herbicidas nos solos são processos dinâmicos e únicos para cada relação solo-herbicida. Neste trabalho, a meia-vida do diuron foi determinada em cinco solos (Latossolo Vermelho Amarelo, Latossolo Vermelho e Latossolo Amarelo), com diferentes valores de pH. As concentrações do diuron foram determinadas em amostras dos referidos solos coletadas em oito épocas (1, 8, 15, 22, 36, 66, 96 e 156 dias após a aplicação do herbicida na dose 3,0kg ha-1). Em uma parte dessas amostras, foi feita a quantificação do diuron por cromatografia líquida de alta eficiência e, na outra parte, os testes biológicos, visando à confirmação dos resultados das análises cromatográficas. Constatou-se que a persistência do diuron é dependente dos atributos físicos e químicos dos solos. Todavia, a correção do pH do solo favoreceu apenas a degradação do herbicida em solos arenosos com baixo teor de matéria orgânica. A meia-vida do diuron nos solos estudados variou de 40 a 91 após a sua aplicação, sendo maior no solo com maior teor de matéria orgânica. Esses resultados foram confirmados pelos testes biológicos que se mostraram eficientes e complementares às análises cromatográficas.Item Otimização e validação da técnica de extração líquido-líquido com partição em baixa temperatura (ELL-PBT) para piretróides em água e análise por CG(Química Nova, 2007-05) Vieira, Heulla Pereira; Neves, Antônio Augusto; Queiroz, Maria Eliana Lopes Ribeiro deThe liquid-liquid extraction with the low temperature partition technique was developed for the analysis of four pyrethroids in water by CG. Using a factorial design the extraction technique was optimised evaluating the effect of the variables ionic strength, contact time and proportion between sample and solvent volumes. The validation parameters sensitivity, precision, accuracy and detection and quantification limits were evaluated. The LOD and LOQ of the method varied from 1.1 to 3.2 μg L-1 and 2.7 to 9.5 μg L-1 , respectively.Item Otimização, validação e aplicação de método para determinação da concentração residual de difenoconazol em morangos após múltiplas aplicações(Química Nova, 2013-09-10) Heleno, Fernanda Fernandes; Queiroz, Maria Eliana Lopes Ribeiro de; Neves, Antônio Augusto; Oliveira, André Fernando deDifenoconazole residues in strawberry fruit cultivated in pots were estimated using the solid-liquid extraction with low temperature partition (SLE/LTP) method for sample preparation and gas chromatography with electron capture detection (GC/ECD) for analysis. The optimized method presented excellent recovery values from fortified samples and reproducibility (average recovery values ≥ 98%; CV values < 15%). Linearity of response was demonstrated (r = 0.995) with a detection limit of 9 µg kg-1. The method was successfully applied for the determination of difenoconazole residues in strawberries. Based on these results, the fungicide dissipates quickly, but the residual concentration increases after multiple applications.Item Ozone treatment for pesticide removal from carrots: Optimization by response surface methodology(Food Chemistry, 2017-09-26) Souza, Lauana Pellanda de; Faroni, Lêda Rita D'Antonino; Heleno, Fernanda Fernandes; Pinto, Frederico Garcia; Queiroz, Maria Eliana Lopes Ribeiro de; Prates, Lucas Henrique FigueiredoThe present study aimed to optimize ozone (O3) treatments, as gas and dissolved in water, to remove difenoconazole and linuron in carrots. We employed a central composite design to study three variables governing the efficacy of treatments: O3 concentration, temperature and treatment time. The temperature did not influence the efficacy of treatments. The removal percentage of pesticides increases with increases in ozone concentration and the time of treatment. O3 application promoted the removal of more than 80% of pesticides when the roots were exposed for approximately 120 min at 5 and 10 mg L−1, respectively, in treatments with O3 as gas and dissolved in water. After storage, pesticide removal was higher than 98% for difenoconazole and 95% for linuron. The degradation products from the pesticides resulting from treatment were monitored, but none were found. This is the first report demonstrating the removal of difenoconazole and linuron from carrots by ozone.Item Pesticide determination in tomatoes by solid–liquid extraction with purification at low temperature and gas chromatography(Food Chemistry, 2010-07-01) Pinho, Gevany Paulino de; Neves, Antônio Augusto; Queiroz, Maria Eliana Lopes Ribeiro de; Silvério, Flaviano OliveiraIn this work, a simple and low cost method, based on solid–liquid extraction with low temperature purification (SLE–LTP), was optimized and validated for the determination of chlorpyrifos, λ-cyhalothrin, cypermethrin and deltamethrin in tomato samples. The analyses were performed by the GC–ECD and confirmed by the GC–MS. The method requires 4 g of tomato and an extraction mixture (8.0 mL acetonitrile, 0.5 mL water and 1.5 mL ethyl acetate), which was established by mixture experimental design. After optimization, pesticide recovery rates ranged from 79% to 97%, with a standard deviation of less than 5%. The SLE–LTP analytical characteristics were compared very favorably to the matrix solid phase dispersion technique, which used ethyl acetate and Florisil for extraction.Item Síntese e caracterização nutricional de plasteína obtida da proteína da folha de mandioca, da soja e do soro de queijo(Revista Ceres, 2000-01) Souza, Eliana Carla Gomes de; Miranda, Luis Carlos Guedes de; Nagem, Tanus Jorge; Oliveira, Tânia Toledo de; Costa, Neusa Maria Brunoro; Queiroz, Maria Eliana Lopes Ribeiro de; Neves, Antônio Augusto; Rezende, Jorge Luiz MartinsEste estudo foi conduzido com o objetivo de testar o aproveitamento de fontes protéicas de baixo custo (folha de mandioca, soro de queijo e soja), por intermédio da reação da plasteína, para obtenção de um produto com propriedades físico-químicas e nutricionais satisfatórias para fins na alimentação humana. 0 isolado protéico das folhas de mandioca, da soja e do concentrado de soro ultrafiltrado, após desengorduramento, foi submetido separadamente à hidrólise enzimática e ressíntese. O teor protéico da plasteína precipitada e do sobrenadante de plasteína foi de 52,6% e 72,0%, respectivamente, sendo o teor protéico do sobrenadante da plasteina superior ao do concentrado protéico de soro ultrafiltrado e do isolado protéico de folha de mandioca. Os resultados da atividade de urease demonstraram que houve destruição quase completa de todos esses fatores. Os valores do Quociente da Eficiência Líquida Protéica (NPR) das plasteínas não diferiram estatisticamente dos apresentados pela caseína. O valor da Utilização Líquida da Proteína (NPU) da plasteína precipitada não diferiu estatisticamente da caseína e o do sobrenadante de plasteína foi inferior ao padrão de caseína. A plasteína precipitada e o sobrenadante de plasteína apresentaram valores de digestibilidade (D) significativamente inferiores (P<0,05) ao padrão, com adequação de 70,3% e 91,2%, respectivamente, em relação à caseína. A plasteína precipitada e o sobrenadante de plasteína são boas fontes de cobre e sódio. A plasteína precipitada é boa fonte de ferro, manganês, magnésio e zinco, segundo recomendação do NRC (12). Constam-se que ambos, matérias-primas e produtos obtidos podem ser considerados boas fontes de aminoácidos essenciais, principalmente para adultos e criança após o desmame. Conclui-se que, com a reação de plasteína, há melhoria na qualidade protéica de fontes alternativas.