Determinação de cobalto em vinho e mosto por espectrofotometria de absorção atómica com atomização electrotérmica. Desenvolvimento e validação do método de análise

An electrothermal atomization atomic absorption spectrometry method was optimized to quantify cobalt in musts and wines, especially within quality control scope. As far as wine samples are concerned, the method involves reduced risk of contamination by eliminating prior treatment other than dilution (1:2). For must samples a pre-treatment is needed, in order to destroy the organic matter that could interfere with the analytical determination. A conventional thermal program (with pyrolysis step), with and without matrix modifier [Mg(NO3)2], was developed and optimized. Pyrolysis and atomization curves were studied using a Co standard solution, must and wine samples. The analytical figures of merit of the method such as linearity of the calibration curve, specificity (standard additions test), accuracy, analytical limits and precision were studied using wine samples. The linear dynamic range under optimized conditions was 0.4-10.0 μg/L. The recoveries were between 87% and 98% for all of the wines and addition levels used in the test. The method presents a very satisfactory specificity for red wines, while matrix effect was observed for white wines. The limit of detection in undiluted wines was 0.8 μg/L. Repeatability was lower than 0.7 μg/L (RSD < 5%). For accuracy evaluation, Co content in six wine samples and one Co standard solution, from an international collaborative trial, was determined by ETAAS and ICP-MS with comparable results (in general the differences were lower than 5%). Bearing in mind that must samples are previously digested, it is expected that the method performance parameters are at least as favourable as those observed with wines.-----------------------------------------Apresenta-se a optimização de um método de análise para a determinação de cobalto, em mostos e vinhos, por espectrofotometria de absorção atómica com atomização electrotérmica. A preparação das amostras de vinho consiste na sua diluição (1:2), pelo que o risco de contaminação é reduzido. No caso das amostras de mosto, é necessário eliminar previamente a matéria orgânica, susceptível de causar interferências na determinação analítica. Foi optimizado um programa térmico convencional (com etapa de pirólise), com e sem adição de modificador de matriz [Mg(NO3)2]. As curvas de pirólise e de atomização foram estabelecidas com recurso a uma solução padrão de Co, mosto e vinho tintos. Foram avaliadas as seguintes características do método: linearidade da curva de calibração, especificidade (teste das adições de padrão), exactidão, limites analíticos e precisão. A gama de trabalho do método é de 0.4 a 10.0 μg/L. As taxas de recuperação variaram entre 87% e 98%, para todos os vinhos e níveis de adição utilizados no teste. A especificidade do método é bastante satisfatória para vinhos tintos, tendo sido verificada a existência de efeito de matriz nos vinhos brancos. A quantidade mínima de analito doseável em vinhos é de 0,8 μg/L e o valor da repetibilidade inferior a 0,7 μg/L (CV < 5%). A exactidão do método foi avaliada por comparação de resultados analíticos obtidos por aplicação do método proposto (ETAAS) e de um método ICP-MS, a amostras originárias de um ensaio colaborativo internacional. As diferenças observadas foram, em geral, inferiores a 5%. É de admitir que as características do método (com excepção da praticabilidade), quando aplicado a mosto, sejam no mínimo tão favoráveis quanto aquelas observadas na sua aplicação a vinhos, uma vez que as amostras de mosto são previamente mineralizadas

Yield and seed chemical composition of Lupinus mutabilis in Portugal

Lupinus mutabilis Sweet (tarwi), being cultivated for thousands of years in the Andean region, is regarded as a potential crop for Europe, especially because of its high protein and oil content. The objective of this study was to revise the productivity and seed composition analyses of several tarwi accessions conducted over several years, in a Mediterranean environment (Lisbon, Portugal), in order to select more suitable lines. The productivity, although low (bellow 2 t/ha, in average), and variable (ranging from 0.26 to 6.0 t/ha), indicates that it should be possible to obtain lines with productivity levels high enough to make of this species a non-irrigated autumn-sown legume crop. These results are more encouraging when compared with the lower yields obtained in central Europe, where indeterminate growth also often causes unsurpassed difficulties. The chemical composition of tarwi seeds obtained in this Mediterranean environment reaches very high levels both in the protein content (up to 50%) and in oil (up to 19%). It is possible to select plants for higher oil levels with little reduction on the protein content. Seeds seem to have a slightly lower protein content than when obtained under central European conditions, but with oil contents consistently higher. Presently, the main obstacles to be transposed in order to make tarwi a crop for the Mediterranean area are: to increase cold and frost tolerance, in order to adapt it to colder winters than those in coastal areas; to increase seed yield and oil content (without reducing protein); to increase resistance to pests and diseases and a better competition against weeds; and to optimise the plant architecture in order to maximise pod and seed set without compromising productive flexibility (so much necessary to face the typical Mediterranean climate interanual variability)info:eu-repo/semantics/publishedVersio

Desenvolvimento de um procedimento de mineralização de mosto para análise elementar por digestão por microondas

Analytical NoteThe present work describes the development and validation of a high pressure microwave-assisted mineralization procedure for the determination of metals in grape must by spectrometric techniques. Metals of special oenological and food safety importance (Al, Co, Cu, Cd, Pb) were used as model elements to achieve the optimum working conditions. The study was conducted by monitoring their concentration in experimental samples by ETAAS. Different combinations of HNO3 and H2O2 were tested and an optimal volume of 1 mL of each reagent, added to 2 mL of sample, was selected for further studies. In comparison with experimental conditions described in literature for the mineralization of grape must and wine by HPMW, the proposed procedure requires very low reagent consumption. Time and temperature were regarded as factors in the optimization study of microwave oven program, resulting in 72 minutes of extension including ventilation. The procedure trueness and precision were evaluated using grape must and wine samples. For each element three different levels of addition were performed. The recovery range was from 94% (Co) to 113% (Pb) in grape must and from 96% (Cu) to 128% (Al) in wine. Relative standard deviations ranged from 1% (Cd) to 11% (Al) in grape must and from 2% (Cd, Pb) to 9% (Co) in wine (n = 10). The proposed procedure is suitable for grape must and wine mineralization with a view to trace element analysis

Effect of bentonite characteristics on the elemental composition of wine

Physical, chemical, and mineralogical characteristics of six bentonites were assessed and related to their elemental release to wine. Extraction essays of bentonites in wine at three pH levels were carried out. The multielemental analysis of bentonites and wines was performed by atomic absorption spectrometry (AAS) and inductively coupled plasma mass spectrometry (ICP-MS). Bentonite addition resulted in significantly higher concentrations of Li, Be, Na, Mg, Al, Ca, Sc, V, Mn, Fe, Co, Ni, Ga, Ge, As, Sr, Y, Zr, Nb, Mo, Cd, Sn, Sb, Ba, W, Tl, Bi, and W. In contrast, the concentrations of B, K, Cu, Zn, and Rb significantly decreased. A strong correlation between Na concentrations of treated wines and its content in bentonite exchange complex was observed. Al and Fe contents reflected bentonite extractable aluminous and ferruginous constituents, while Be, Mg, Ca, V, Mn, Ni, Ge, Zr, Nb, Mo, Sn, Sb, Tl, Pb, and U concentrations reflected the elemental composition of bentonites. Several nonconformances with OIV specifications demonstrated the need for an effective control

Contaminant elements in wines: a review

Approximately ten years after a first critical review of the authors on the occurrence of contaminant elements in wine, the subject remains of the utmost importance within the technological, food safety and legal concern. Future developments on toxicological and analytical field, as well as on international trade, will promote changes in existing regulations. Increasing concern with wine food safety may lead to the enlargement of the list of elements to control, and the change of terms in which the acceptable maximum limits are established. This paper, based on the introduction chapter of a Doctoral Thesis, presents a brief approach to the mineral composition of wine, and reviews a large group of contaminant elements (information also systematized in a table), including research results obtained by the authors. Aspects such as origin, levels of occurrence, evolution throughout the technological processes, potential sources of contamination, distribution under different chemical species, toxicity, analytical determination and acceptable maximum limits, vary considerably among contaminant elements

A sensory and chemical approach to the aroma of wooden aged Lourinhã wine brandy

The maturation of wine brandies in wooden barrels origin many sensory and physical-chemical changes in these alcoholic beverages. This work studies the odorants in different aged brandies from Lourinhã. These brandies were analyzed by gas chromatography coupled to olfactometry (CG-O). A panel taster profiled these brandies and the identified odorants were also quantified by gas chromatography coupled to a flame ionization detector (CG-FID). The CG-O results showed 29 identified odorants (alcohols, esters, acids and phenols. Some of them are proceeding from the distillate while others are extracted from the wood. The analysis of the correlation between the sensory profiles and the odorant quantification pointed out the relevance of several wood compounds for the brandy aroma, namely the vanillin, volatile phenols and furanic aldehydes. These compounds presented important correlations with several olfactory attributes like vanilla, toasted dried fruits, woody, which influence positively the quality of the brandies

A new approach on communications architectures for intelligent transportation systems

A Vehicular Adhoc Network (VANET) is a generic communications conceptualization that can be applied to Intelligent Transportation Systems (ITS) and its main goal is to allow exchange of information between moving vehicles, fixed infrastructures, pedestrians with personal devices, and all other electronic devices able to connect to a VANET environment. Information exchange between different stakeholders brings a relevant potential to the development of applications to help users in different areas such as traffic safety and efficiency, infotainment and personal comfort. However, due to the expected heterogeneity (different processing power and storage capabilities, communications technologies and mobility patterns) and large scale on the number of devices involved, application interoperability in VANET contexts can be a challenging problem. Non-agnostic standard communications architectures for ITS systems have some deploying limitations and lack important specific implementation details. This paper presents an agnostic VANET architecture (it permits the use of several communication technologies in an open and modular framework), which is an adaption of present standards approach, to be deployed on ITS systems as a mean to overcome their main limitations. (C) 2017 The Authors. Published by Elsevier B.V.This work has been sponsored by the Portugal Incentive System for Research and Technological Development. Project in co-promotion no 002797/2015 (INNOVCAR 2015-2018), and also by COMPETE: POCI-01-0145-FEDER-007043 and FCT - Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2013

Effect of heat treatment on the thermal and chemical modifications of oak and chestnut wood used in brandy ageing

The effects of temperature and frequency of moistening during the first phase of the heath treatment (bending phase) on the simultaneous response of different kinds of wood (Portuguese chestnut, Rumanian and American oak wood) used in brandy ageing were studied. The evolution of the wood temperature was measured by K thermocouple probes. The wood extractable compounds (phenolic acids, phenolic aldehydes, coumarins and furanic derivatives) were analyzed by HPLC. The results showed that the thermal distribution along the thickness of the stave is influenced by the temperature and frequency of moistening, and also, by the botanical species. It was verified that the bending phase is of great importance for the barrel quality not only for this impact on the physical and mechanical properties of the wood but also for its effect on the wood chemical composition

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P &lt; 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries