Transgenic and non-transgenic soybean seeds were compared in terms of total element concentrations, behavior of elements during sequential extraction fractionation and element bioaccessibility using an in vitro simulated gastrointestinal digestion. The analysis were carried out by ICP-sector field-MS or size-exclusion ICP-MS (25 elements in concentrations varying from ng g⁻¹ to the % level). It seems that transgenic and non-transgenic soybean seeds exhibit statistically significant differences in concentrations of Cu, Fe and Sr, which are also reflected by element contents in water extracts and residues. Additionally, contributions of bioaccessible fractions of Cu, Fe and other elements (Mn, S, Zn) for transgenic soybean seeds appear to be larger than those found in non-transgenic soybean seeds.
The HPLC (anion exchange)-ICP-MS technique was used for the identification (based on retention time of standards) and determination of four selenium species (selenite, selenate, selenomethionine and selenocystine) in plankton (BCR-414), Brazil nuts and urine samples. A recovery of 91% was attained for certified reference materials (BCR-414). Se(IV) was the predominant species in plankton, with the highest selenium concentration in the extract. The Brazil nuts showed only the organic species selenomethionine and selenocystine after water extraction, but after simulated gastrointestinal digestion, only selenomethionine was found as bioaccessible, corresponding to 74% of the total selenium (54.8±4.6 μg g(-1)). Analyses of the urine samples suggested the presence of selenocystine, and significant differences were observed between samples from men and women in terms of the concentration of this species after consumption of Brazil nuts (1 nut per day during 15 days).
This study is aimed at investigating a suitable method for rice sample preparation as well as validating and applying the method for monitoring the concentration of total arsenic, cadmium, and lead in rice by using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Various rice sample preparation procedures were evaluated. The analytical method was validated by measuring several parameters including limit of detection (LOD), limit of quantification (LOQ), linearity, relative bias, and repeatability. Regarding the sample preparation, recoveries of spiked samples were within the acceptable range from 89.3 to 98.2% for muffle furnace, 94.2 to 103.3% for heating block, 81.0 to 115.0% for hot plate, and 92.8 to 108.2% for microwave. Validation parameters showed that the method fits for its purpose, being the total arsenic, cadmium, and lead within the Brazilian Legislation limits. The method was applied for analyzing 37 rice samples (including polished, brown, and parboiled), consumed by the Brazilian population. The total arsenic, cadmium, and lead contents were lower than the established legislative values, except for total arsenic in one brown rice sample. This study indicated the need to establish monitoring programs for emphasizing the study on this type of cereal, aiming at promoting the Public Health.
Apresentamos um estudo interdisciplinar onde condições ambientais, sociais e de saúde são integradas para avaliar o risco de exposição ao arsênio na população de Paracatu, devido à exploração da maior mina de ouro a céu aberto do Brasil. O estudo possui três fases: avaliação da contaminação ambiental; estudo epidemiológico de exposição ambiental humana; exame dos fatores associados aos comportamentos para reduzir o risco de exposição. As águas de consumo humano na área urbana não estão contaminadas com arsênio. Os teores de arsênio em urina indicam exposição mais alta em bairros próximos à mina, em concordância com os dados sobre material particulado atmosférico. A taxa de mortalidade por câncer não se mostrou superior aos controles. As redes sociais e relações de gênero são chave na adoção de comportamentos preventivos. Recomenda-se o estabelecimento de um Programa de Vigilância da exposição ao arsênio, com envolvimento do SUS, ao nível municipal, estadual e federal.
This work reports the use of 2D-HPLC-ICP-MS to enlarge metallomics information when considering soybean seeds. Separations using size exclusion chromatography (SEC) allowed the identification of three metal fractions: the first corresponding to molecular weights from 38.1 to 181.1 kDa, the second from 8.2 to 17.2 kDa and the third from 0.4 to 3.8 kDa. In a second dimension, using anion exchange chromatography (AEX), three sub-fractions containing Fe, Mg and Mn, one containing Cu, and three containing Co, Cu, Mg, Mn and Zn were obtained. After these separations, 33 proteins were identified using the ESI-MS/MS technique, and divided into four functional categories: plant growth/cell division, protein destination and storage, metabolism and unclassified proteins. Among the identified proteins, proteins previously related to metals were found.
Programas de Ensaios de Proficiência (PEP) têm por finalidade a avaliação do desempenho de um laboratório, contra critérios preestabelecidos por meio de comparações interlaboratoriais, que são utilizados como ferramenta de avaliação externa na demonstração da confiabilidade analítica laboratorial, além de ser um dos requisitos para o processo de acreditação. Para laboratórios analíticos que atuam no controle da qualidade de produtos e serviços destinados ao consumo humano, a obtenção de resultados confiáveis é fundamental para a credibilidade e para a garantia da qualidade das suas funções. Os resultados emitidos pelos laboratórios são avaliados pelos Provedores de Ensaios de Proficiência por meio de métodos estatísticos (índice z, índice zeta, erro normalizado, entre outros) para verificar a eficácia de seus desempenhos. Este trabalho teve como meta avaliar a efetividade da participação do Núcleo de Contaminantes Inorgânicos (NCI) do Centro de Contaminantes do Instituto Adolfo Lutz em diferentes PEPs para metais e semimetais na matriz água, no período compreendido entre 2013 e 2018. Os resultados apresentados demonstraram a efetividade da melhoria contínua realizada na execução das análises pelo NCI e consequentemente o aumento da confiabilidade dos resultados analíticos. Este trabalho visa divulgar, incentivar e fornecer ferramentas aos laboratórios analíticos que atuam no controle da qualidade de produtos e serviços destinados à saúde pública, para auxiliar a implantação de medidas corretivas e preventivas, permitindo seu aprimoramento analítico contínuo.
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