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Cyclic voltammetry : a tool to quantify 2,4,6-trichloroanisole in aqueous sampl...
Peres, A. M.; Freitas, P.; Dias, Luís G.; Sousa, Mara E. B. C.; Castro, L. M.; Veloso, Ana C. A.Chloroanisoles, namely 2,4,6-trichloroanisole, are pointed out as the primary responsible of the development of musty off-flavours in bottled wine, due to their migration from cork stoppers, which results in huge economical losses for wine industry. A prevention step is the detection of these compounds in cork planks before stoppers are produced. Mass spectrometry gas chromatography is the reference method used...
A apicultura em modo de produção biológico: identificação dos principiais entra...
Cabo, Paula; Dias, Luis G.; Vilas-Boas, Miguel; Gomes, MárioA apicultura é uma atividade importante, considerada estratégia para o desenvolvimento sustentável do território pela notável ação que desempenha no mundo rural e no meio ambiente. É uma atividade conservadora, de fácil manutenção, de baixo custo inicial em relação às demais atividades agropecuárias, e uma das poucas no ramo da agropecuária que preenche os requisitos base da sustentabilidade: (a) o económico, p...
Cyclic voltammetry: a tool to quantify 2,4,6-trichloroanisole in aqueous sample...
Peres, António M.; Freitas, Patrícia; Dias, Luís G.; Sousa, Mara E. B. C.; Castro, Luís M.; Veloso, Ana C. A.Chloroanisoles, namely 2,4,6-trichloroanisole, are pointed out as the primary responsible of the development of musty off-flavours in bottled wine, due to their migration from cork stoppers, which results in huge economical losses for wine industry. A prevention step is the detection of these compounds in cork planks before stoppers are produced. Mass spectrometry gas chromatography is the reference method used...
Determination of 2,4,6-trichloroanisole by cyclic voltammetry
Freitas, P.; Dias, Luís G.; Peres, A. M.; Castro, L. M.; Veloso, Ana C. A.The electrochemical reduction of 2,4,6-trichloroanisole (TCA), a chlorinated arene with electron-donating substituents, was evaluated by cyclic voltammetry (CV). TCA is a major concern for the winery industry since it is related with “cork taint”, a wine defect. The results obtained showed that CV could be used to detect and quantify TCA in standard solutions. Linear relationships could be set between the curre...
Application of an electronic tongue to detect gliadins in gluten-free foods
Peres, A. M.; Dias, Luís G.; Veloso, Ana C. A.; Meirinho, S. G.; Morais, J. Sá; Machado, A. A. S. C.Celiac disease is an autoimmune-mediated disorder triggered in genetically susceptible individuals by the ingestion of some gluten proteins, namely gliadins. To prevent inadvertent gluten consumption, the Commission Regulation (EC) Nº41/2009 will implement labelling foods as “gluten-free” or “low-gluten content”[1]. The feasibility of an all-solid-state potentiometric electronic tongue to detect the contaminati...
UV spectrophotometry method for the monitoring of galacto-oligosaccharides prod...
Dias, Luís G.; Veloso, Ana C. A.; Correia, Daniela M.; Rocha, Orlando; Torres, D.; Rocha, I.; Rodrigues, L. R.; Peres, A. M.Monitoring the industrial production of galacto-oligosaccharides (GOS) requires a fast and accurate methodology able to quantify, in real time, the substrate level and the product yield. In this work, a simple, fast and inexpensive UV spectrophotometric method, together with partial least squares regression (PLS) and artificial neural networks (ANN), was applied to simultaneously estimate the products (GOS) and...
A computational study of substituted flavylium salts and their quinonoidal conj...
Freitas,Adilson A.; Shimizu,K.; Dias,Luís G.; Quina,Frank H.The electronic transitions for flavylium cations and quinonoidal bases of 17 substituted flavylium salts have been studied at semiempirical and DFT (density functional theory) levels. Solvent effect on electronic spectra was included by Polarizable Continuum Model, PCM. We assigned longest-wavelength absorption maxima to HOMO -> LUMO transition. Both levels of theory gave good results for electronic transitions...
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