Jorge Moreda-Piñeiro

Bio: Jorge Moreda-Piñeiro is an academic researcher from University of A Coruña. The author has contributed to research in topics: Atomic absorption spectroscopy & Arsenic. The author has an hindex of 27, co-authored 100 publications receiving 1971 citations. Previous affiliations of Jorge Moreda-Piñeiro include University of Santiago de Compostela.

In-vivo and in-vitro testing to assess the bioaccessibility and the bioavailability of arsenic, selenium and mercury species in food samples

Abstract: In-vivo and in-vitro gastrointestinal (GI) extractions, also known as oral bioaccessibility and bioavailability, are important approaches to assess chemical risk to humans. We give an overview of in-vivo and in-vitro bioaccessibility and bioavailability assays for testing arsenic, selenium and mercury (As, Se and Hg) species from food samples. We critically evaluate the parameters affecting in-vivo and in-vitro processes. In addition, we consider the effect of cooking food on bioaccessibility and bioavailability, and stability and transformation, of species during in-vivo or in-vitro processes. The bioaccessibility and bioavailability of As, Se and Hg species are affected by the sample matrix, cooking food and the experimental conditions applied (gastric and intestinal pH, incubation temperature and residence time). Regarding species degradation and transformation during in-vitro procedures, good stability has been observed for most As species, except for certain arsenosugars. Important transformations during in-vitro processes have been reported for Se species [e.g., conversion of γ-glu-Se-MeSeCys to Se-MeSeCys, and organic Se species (MeSeCys, SeCys2 and SeMet) degradation to inorganic Se]. Finally, we summarize speciation and detection conditions for As, Se and Hg speciation, and quality control to assure reliable measurements.

As, Hg, and Se flue gas sampling in a coal-fired power plant and their fate during coal combustion.

Abstract: As, Hg, and Se are the most volatile elements in the flue gas from a coal-fired power plant. Significant amounts of these elements cause an undesired direct gaseous emission, which leads to a serious environmental health risk. The main focus of this study is to evaluate the possibility of simultaneous sampling of these volatile elements using an accurate official method for Hg (the most volatile element). A study of As, Hg, and Se emissions from a 1400 MW coal-fired power plant equipped with electrostatic precipitators (ESPs) was carried out for the combustion of a mixture of two types of coal. Simultaneous sampling of coal, bottom ash, fly ash, flue gas, and particles associated with the gas phase has been performed. Flue gas has been sampled by the Ontario Hydro Method Sampling Train, an ASTM method for Hg speciation. This sampling method was tested for As and Se sampling. As and Se determinations have been performed by HG-AAS, and Hg has been determined by CV-AAS. The results were used to examine the following: overall mass balances, relative distribution of these elements in the coal-fired power plant; As, Hg, and Se concentrations in coal and combustion residues; and predominant oxidation state for Hg in flue gas. The mass balances obtained for As, Hg, and Se were satisfactory in all cases; nevertheless, relative enrichment values in fly ash for As and Se were low; therefore, we concluded that As sampling in flue gas can be conducted by application of the Ontario Hydro Method; nevertheless Se released in the gas phase is not completely collected by this sampling train. Application of this sampling method allowed for performance of Hg speciation. The results indicated that Hg(II) was the predominant species in flue gas. It has also been proved that 24%, more than 99.8%, and 90% for As, Hg, and Se in the stack emissions, respectively, were in the gaseous phase.

Usefulness of the chemical modification and the multi-injection technique approaches in the electrothermal atomic absorption spectrometric determination of silver, arsenic, cadmium, chromium, mercury, nickel and lead in sea-water

Abstract: A critical study of the use of chemical modification and background correction systems was carried out for the direct determination of several high and medium volatility and refractory metals (Ag, As, Cd, Cr, Hg, Ni and Pb) in sea-water samples by ETAAS. The influence of increasing sea-water inorganic matrix on the atomic signals, by the introduction of a large injection volume, was evaluated for different chemical modifiers [mainly Pd(NO3)2 , Mg(NO3)2 and also reduced palladium, which was done by using different reducing agents, viz., ascorbic acid, hydroxylamine hydrochloride and citric acid] and with two background correction systems [deuterium arc background correction (DABC) and Zeeman effect background correction (ZEBC)]. The influence of the salt matrix from sea-water was found to be very important for medium volatility metals such as Ag, As and Pb (charring temperatures between 1100 and 1400 °C), whereas for refractory (Cr and Ni, with charring temperatures of 1500 and 1600 °C, respectively) and high volatility metals such as Cd and Hg (charring temperature of 500 and 300 °C, respectively) this influence was insignificant. By using chemical modification and background correction, the interferences from the saline matrix were lowered for all metals studied (except Pb) and their direct determination in sea-water samples became possible. For high and medium volatility metals the use of reduced palladium offers better analytical performance than the use of palladium nitrate, while the addition of reducing agents does not improve the analytical performance for refractory metals.

Algae as nutritional and functional food sources: revisiting our understanding

Abstract: Global demand for macroalgal and microalgal foods is growing, and algae are increasingly being consumed for functional benefits beyond the traditional considerations of nutrition and health. There is substantial evidence for the health benefits of algal-derived food products, but there remain considerable challenges in quantifying these benefits, as well as possible adverse effects. First, there is a limited understanding of nutritional composition across algal species, geographical regions, and seasons, all of which can substantially affect their dietary value. The second issue is quantifying which fractions of algal foods are bioavailable to humans, and which factors influence how food constituents are released, ranging from food preparation through genetic differentiation in the gut microbiome. Third is understanding how algal nutritional and functional constituents interact in human metabolism. Superimposed considerations are the effects of harvesting, storage, and food processing techniques that can dramatically influence the potential nutritive value of algal-derived foods. We highlight this rapidly advancing area of algal science with a particular focus on the key research required to assess better the health benefits of an alga or algal product. There are rich opportunities for phycologists in this emerging field, requiring exciting new experimental and collaborative approaches.