A simple and green analytical method for the determination of formaldehyde

A green spectrophotometric analytical method for determination of formaldehyde in commercial samples was designed and investigated. Replacement of hazardous reagents was explored to attain the clean chemistry standards. The method is based on formaldehyde reaction with chromotropic acid in the presence of magnesium sulphate producing a stable complex Mg(2+)/cyclotetrachromotropylene (lambda(max) = 535 nm). To the best of our knowledge, there are no reports on the use of the above mentioned reaction for this determination. The experimental conditions were optimized by the response surface methodologies. Beer's Law is obeyed in a concentration range of 3 to 11 mg L(-1) of formaldehyde with a correlation coefficient of 0.999. The proposed method was applied for the determination of formaldehyde in commercial disinfectants and deffrizing hair products. The results were favorably compared with those of the official method, with good accuracy and precision

Avaliação e adaptação das condições da EN 14103 para quantificação de ésteres em biodieseis etílicos puros de soja, babaçu, palma e sebo bovino e em suas misturas

Nos últimos anos o biodiesel foi agregado à matriz energética brasileira como um componente de grande importância, sobretudo do ponto de vista estratégico e ambiental. O biodiesel, obtido a partir de óleos/gorduras, apresenta várias vantagens enquanto pretenso substituto do diesel. A grande diversidade de óleos e gorduras possibilita encontrar uma gama de matérias primas dispersas em todo o território brasileiro com grande potencial para produção de biodiesel. Porém, biodieseis produzidos a partir de diferentes matérias primas podem apresentar restrições relacionadas às metodologias utilizadas no controle de sua qualidade. Os métodos normalizados estabelecidos pela ANP às vezes não se aplicam a biodieseis obtidos a partir de certas fontes de triacilglicerídeos. A EN 14103, norma que estabelece o método para determinação do teor de éster em biodieseis, foi elaborada para a análise de biodieseis exclusivamente metílicos obtidos de óleos/gorduras que possuem ésteres de cadeias carbônicas predominantes na faixa de C14:0 a C24:1. A norma estabelece o C17:0 (heptadecanoato de metila) como padrão interno. Considerando o cenário nacional, a EN 14103 torna-se inadequada para a quantificação de biodieseis etílicos e metílicos que apresentam quantidades relevantes de ésteres de cadeias carbônicas curtas (C8:0 a C12:0), além disso, a utilização do C17:0 como padrão interno inviabiliza também a quantificação de biodieseis que o contém em sua composição. Através de uma avaliação e adaptação das condições da EN 14103, foi possível quantificar biodieseis etílicos provenientes de matérias primas e/ou “blends” que possuem cadeias carbônicas na faixa C8:0 a C24:1, utilizando padrões tanto metílicos quanto etílicos. O estudo viabilizou ainda a quantificação de biodieseis etílicos que possuem o C17:0 em sua...In the last years the biodiesel was added to the Brazilian energetic matrix as a great important component, mainly under the strategic and environmental aspects. The biodiesel, obtained from oil/fat, presents several advantages as substitute of the diesel. The great variety of oils and fats allow finding a range of raw materials dispersed throughout the Brazilian territory with huge potential for producing biodiesel. However, restriction related to the methodology employed in the biodiesel quality control can be related by the variety of raw materials. Nor all the standardized methods established by the ANP are applied to the biodiesel obtained from any oleaginous. EN 14103, method applied to quantify the biodiesel ester content, was elaborated to analysis exclusively methylic biodiesel produced from oil/fat, which contains carbonic chain esters between C14:0 and C24:1. This method employs C17:0 (methyl heptadecanoate) like internal standard. Considering the national scene, this method becomes inadequate for the ethylic biodiesel quantification that presents relevant quantities of short carbon chains esters (C8:0 and C12:0). Furthermore, the use of C17:0 as internal standard also affect the biodiesel quantification containing this ester in his composition. Through an evaluation and adaptation of the EN 14103 conditions, was possible to quantify ethylic biodiesel obtained from raw materials and/or blends that have carbon chains between C8:0 and C24:1, using both methylic and ethylic standards. This study also enabled the quantification of ethyl biodiesel having the C17:0 in his composition, using the methylic C17:0 (methyl heptadecanoate) as internal standardCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Breakpoint delineation in 5p‐ patients leads to new insights about microcephaly and the typical high‐pitched cry

Abstract Background Cri du chat syndrome (CdCS) is a rare syndrome caused by a partial or complete deletion of the short arm of chromosome 5 (5p‐). The main clinical features include a high‐pitched cry, facial asymmetry, microcephaly, round face at birth, epicanthal folds, hypotonia, delayed growth and development. Methods We studied 14 Brazilian patients with CdCS using genomic array in order to better define the 5p breakpoints and recognize copy number variations (CNVs) that contribute to clinical manifestations associated with the syndrome. Results Array confirmed terminal deletions in 13 patients and an interstitial deletion in one patient. It was also possible to map the breakpoints and associate a genomic region of 4.7 Mb to the development of head circumference and cat‐like cry. We also found other CNVs concomitant to the 5p deletion including a 9p duplication, a 17q deletion, and a 22q deletion in three different patients. Conclusion With advancements of molecular cytogenomic methods in the last two decades, it was possible to evidence cryptic alterations and improve the genotype–phenotype correlation. In this work, we describe a new genomic region associated with microcephaly and cat‐like cry and highlight the importance of precise delineation of 5p deletion breakpoints and detection of other CNVs in CdCS patients to improve genotype–phenotype correlation to perform a complete clinical and molecular diagnosis