Determination of ametryn in soils via microwave-assisted solvent extraction coupled to anodic stripping voltammetry with a gold ultramicroelectrode

An extraction-anodic adsorptive stripping voltammetric procedure using microwave-assisted solvent extraction and a gold ultramicroelectrode was developed for determining the pesticide ametryn in soil samples. The method is based on the use of acetonitrile as extraction solvent and on controlled adsorptive accumulation of the herbicide at the potential of 0.50 V (vs. Ag/AgCl) in the presence of Britton-Robinson buffer (pH 3.3). Soil sample extracts were analysed directly after drying and redissolution with the supporting electrolyte but without other pre-treatment. The limit of detection obtained for a 10 s collection time was 0.021 µg g-1. Recovery experiments for the global procedure, at the 0.500 µg g-1 level, gave satisfactory mean and standard deviation results which were comparable to those obtained by HPLC with UV detection

Construction and evaluation of cysteine selective electrodes for FIA analysis of pharmaceuticals

A flow injection analysis (FIA) system comprising a cysteine selective electrode as detection system was developed for determination of this amino acid in pharmaceuticals. Several electrodes were constructed for this purpose, having PVC membranes with different ionic exchangers and mediator solvents. Better working characteristics were attained with membranes comprising o-nitrophenyl octyl ether as mediator solvent and a tetraphenylborate based ionic-sensor. Injection of 500 µL standard solutions into an ionic strength adjuster carrier (3x10-3 M) of barium chloride flowing at 2.4mL min-1, showed linearity ranges from 5.0x10-5 to 5.0x10-3 M, with slopes of 76.4±0.6mV decade-1 and R2>0.9935. Slope decreased significantly under the requirement of a pH adjustment, selected at 4.5. Interference of several compounds (sodium, potassium, magnesium, barium, glucose, fructose, and sucrose) was estimated by potentiometric selectivity coefficients and considered negligible. Analysis of real samples were performed and considered accurate, with a relative error to an independent method of +2.7%

Enoturismo e tendências de competitividade: perspetivas do contexto português

O Enoturismo é um segmento do mercado muito vinculado aos destinos rurais, onde as pessoas podem usufruir da diferença e autenticidade dos seus produtos locais para promover a atividade turística, estimulando assim a procura de uma determinada região. Esta tipologia de oferta tem evidenciado um crescimento em Portugal e em todo o mundo ao longo dos últimos anos, com exceção dos últimos dois em virtude da pandemia. É um segmento do mercado turístico atualmente relevante e apresenta um grande potencial de crescimento a médio e longo prazo. A presente investigação pretende constituir-se como um contributo para aprofundar o conhecimento sobre o mesmo e/ou abrir horizontes de investigação nesta área do Enoturismo, principalmente na região Demarcada do Douro, Concelho de São João da Pesqueira, assim como identificar um melhor conhecimento do setor, nomeadamente na área da procura, por forma a possibilitar o desenvolvimento do produto e, também, identificar as motivações na escolha do destino turístico. Foca-se na análise do tema do enoturismo com uma enorme preponderância na Região Demarcada do Douro, em particular no Concelho de São João da Pesqueira. O objetivo geral da investigação consiste em compreender a importância do enoturismo na promoção do destino São João da Pesqueira. Por conseguinte, como objetivos específicos, o estudo pretende identificar as preferências do turista, as motivações na escolha do destino turístico, identificar um melhor conhecimento do setor, nomeadamente na área da procura, para assim possibilitar o desenvolvimento do produto, identificar e valorizar a perspetiva enoturística e identificar o impacto do enoturismo no desenvolvimento regional e local. Nas principais conclusões, é possível destacar os pontos fortes do destino, as características únicas, a paisagem, o produto (vinho), a história e a diversidade de produtores de vinhos, as novas atrações, proximidade, infraestruturas, clima, ciclo de vida do turismo e dinâmica do visitante, tendo em conta se é a primeira visita ou não. Em relação à influência do enoturismo no território, é fundamental e assume um papel crucial no Concelho, de forma transversal, uma vez que está relacionado com outras atividades, em que assume um papel de divulgação por todo o mundo, é um setor em plena expansão e que atrai imensos turistas à região, que fixa pessoas no interior, pois também dá muito trabalho a quem lá vive. Adicionalmente, o enoturismo pode ser uma alavanca na cocriação sustentável de novas experiências de turismo, de ideias inovadoras para se implementarem no concelho futuramente, que coincidem com alguma ideias já existentes em outras Regiões e Países. Relativamente ao futuro do setor do enoturismo, as estratégias passam pela valorização do destino, por apostar na diferenciação pela qualidade e pela inovação de novas propostas, como por exemplo a criação de rotas turísticas, ou a criação de novos hotéis envolvidos com a paisagem, pela diversidade vitivinícola, pela sua história. A mesma será de evolução, as regiões têm a função de valorizar a sua imagem de marca, aproveitando o enoturismo, as características do seu vinho, juntamente com a sua gastronomia, valorizando os seus recursos particulares e endógenos, e neste sentido proporciona experiências únicas, de modo a divulgar e promover o turismo na região e por sua vez o impacto económico.Wine Tourism is a market segment closely linked to rural destinations, where people can take advantage of the difference and authenticity of their local products to promote tourism activity, thus stimulating the demand for a particular region. This supply has experienced a very significant increase in Portugal and worldwide over the last few years, except for the last two due to the pandemic. It is a segment of the tourism market currently relevant and has great potential for growth in the medium and long term. This research aims to be a contribution to deepen the knowledge about it and/or to open research horizons in this area of wine tourism, especially in the Demarcated Douro region, Municipality of São João da Pesqueira, as well as to identify a better knowledge of the sector, particularly in the area of demand, in order to enable product development and also to identify the motivations in the choice of tourist destination. It focuses on the analysis of wine tourism with a huge preponderance in the Douro Demarcated Region, particularly in the Municipality of São João da Pesqueira. The general objective of the research is to understand the importance of wine tourism in promoting the destination São João da Pesqueira. Therefore, as specific objectives, the study aims to identify tourist preferences, the motivations in choosing a tourist destination, identify a better knowledge of the sector, particularly in the area of demand, to enable product development, identify and enhance the wine tourism perspective and identify the impact of wine tourism on regional and local development. In the main conclusions, it is possible to highlight the destination's strengths, unique characteristics, the landscape, the product (wine), the history and diversity of wine producers, new attractions, proximity, infrastructure, climate, tourism life cycle, and visitor dynamics, considering whether it is the first visit or not. Regarding the influence of wine tourism in the territory, it is fundamental and assumes a crucial role in the region, in a transversal way, since it is related to other activities, in which it assumes a role of dissemination throughout the world; it is a sector in full expansion attracting many tourists to the region and by anchoring the labor force within the territory, because it also provides business activity to those who live there. Additionally, wine tourism can be a lever in the sustainable co-creation of new tourism experiences, of innovative ideas to be implemented in the territory in the future, which coincide with some ideas already existing in other regions and countries. Considering the future of the wine tourism sector, the strategies include the valorization of the destination, through the differentiation for the quality and innovation of new proposals, as for the creation of tourism routes, or new hotels involved with the landscape, by the wine diversity, by its history. The regions must enhance their brand image, taking advantage of wine tourism, the characteristics of its wine, along with its gastronomy, their endogenous resources, and in this sense provide unique experiences, to disseminate and promote tourism in the region and in turn the economic impact.info:eu-repo/semantics/publishedVersio

Analysis of PCBs in soils and sediments by microwave-assisted extraction, headspace-SPME and high resolution gas chromatography with ion-trap tandem mass spectrometry

A procedure for the determination of seven indicator PCBs in soils and sediments using microwave-assisted extraction (MAE) and headspace solid-phase microextraction (HS-SPME) prior to GC-MS/MS is described. Optimization of the HS-SPME was carried out for the most important parameters such as extraction time, sample volume and temperature. The adopted methodology has reduced consumption of organic solvents and analysis runtime. Under the optimized conditions, the method detection limit ranged from 0.6 to 1 ng/g when 5 g of sample was extracted, the precision on real samples ranged from 4 to 21% and the recovery from 69 to 104%. The proposed method, which included the analysis of a certified reference material in its validation procedure, can be extended to several other PCBs and used in the monitoring of soil or sediments for the presence of PCBs

Development and validation of a novel method for the analysis of chlorinated pesticides in soils using microwave-assisted extraction–headspace solid phase microextraction and gas chromatography–tandem mass spectrometry

A new procedure for determining eleven organochlorine pesticides in soils using microwave-assisted extraction (MAE) and headspace solid phase microextraction (HS-SPME) is described. The studied pesticides consisted of mirex, α- and γ-chlordane, p,p’-DDT, heptachlor, heptachlor epoxide isomer A, γ-hexachlorocyclohexane, dieldrin, endrin, aldrine and hexachlorobenzene. The HS-SPME was optimized for the most important parameters such as extraction time, sample volume and temperature. The present analytical procedure requires a reduced volume of organic solvents and avoids the need for extract clean-up steps. For optimized conditions the limits of detection for the method ranged from 0.02 to 3.6 ng/g, intermediate precision ranged from 14 to 36% (as CV%), and the recovery from 8 up to 51%. The proposed methodology can be used in the rapid screening of soil for the presence of the selected pesticides, and was applied to landfill soil samples

Determination of total petroleum hydrocarbons in soil from different locations using infrared spectrophotometry and gas chromatography

Total petroleum hydrocarbons (TPH) are important environmental contaminants which are toxic to human and environmental receptors. Several analytical methods have been used to quantify TPH levels in contaminated soils, specifically through infrared spectrometry (IR) and gas chromatography (GC). Despite being two of the most used techniques, some issues remain that have been inadequately studied: a) applicability of both techniques to soils contaminated with two distinct types of fuel (petrol and diesel), b) influence of the soil natural organic matter content on the results achieved by various analytical methods, and c) evaluation of the performance of both techniques in analyses of soils with different levels of contamination (presumably non-contaminated and potentially contaminated). The main objectives of this work were to answer these questions and to provide more complete information about the potentials and limitations of GC and IR techniques. The results led us to the following conclusions: a) IR analysis of soils contaminated with petrol is not suitable due to volatilisation losses, b) there is a significant influence of organic matter in IR analysis, and c) both techniques demonstrated the capacity to accurately quantify TPH in soils, irrespective of their contamination levels

Determination of carbamate and urea pesticide residues in fresh vegetables using microwave-assisted extraction and liquid chromatography

An analytical multiresidue method for the simultaneous determination of seven pesticides in fresh vegetable samples, namely, courgette (Cucurbita pepo), cucumber (Cucumis sativus), lettuce (Lactuca sativa, Romaine and Iceberg varieties) and peppers (Capsicum sp.) is described. The procedure, based on microwave-assisted extraction (MAE) and analysis by liquid chromatography– photodiode array (LC–PDA) detection was applied to four carbamates (carbofuran, carbaryl, chlorpropham and EPTC) and three urea pesticides (monolinuron, metobromuron and linuron). Extraction solvent and the addition of anhydrous sodium sulphate to fresh vegetable homogenate before MAE were the parameters optimised for each commodity. Recovery studies were performed using spiked samples in the range 250–403 µgkg- 1 in each pesticide. The pesticide residues were extracted using 20mL acetonitrile at 60 ºC, for 10 min. Acceptable recoveries and RSDs were attained (overall average recovery of 77.2% and RSDs are lower than 11%). Detection limits ranged between 5.8 µgkg- 1 for carbaryl to 12.3 µgkg- 1 for carbofuran. The analytical protocol was applied for quality control of 41 fresh vegetable samples bought in Oporto Metropolitan Area (North Portugal). None of the samples contained any detectable amounts of the studied compounds

Extracção assistida por microondas de pesticidas em produtos agrícolas

Tese de Mestrado. Engenharia do Ambiente. Faculdade de Engenharia. Universidade do Porto. 200

Influência do enoturismo na Região Demarcada do Douro: o caso do Concelho de São João da Pesqueira

O Enoturismo é um segmento do mercado muito vinculado aos destinos rurais, onde as pessoas podem usufruir da diferença e autenticidade dos seus produtos locais para promover a atividade turística, estimulando assim a procura de uma determinada região. Esta tipologia de oferta tem evidenciado um crescimento em Portugal e em todo o mundo ao longo dos últimos anos, com exceção dos últimos dois em virtude da pandemia. É um segmento do mercado turístico atualmente relevante e apresenta um grande potencial de crescimento a médio e longo prazo. A presente investigação pretende constituir-se como um contributo para aprofundar o conhecimento sobre o mesmo e/ou abrir horizontes de investigação nesta área do Enoturismo, principalmente na região Demarcada do Douro, Concelho de São João da Pesqueira, assim como identificar um melhor conhecimento do setor, nomeadamente na área da procura, por forma a possibilitar o desenvolvimento do produto e, também, identificar as motivações na escolha do destino turístico. Foca-se na análise do passado, presente e futuro do tema do enoturismo com uma enorme preponderância na Região Demarcada do Douro, mais precisamente no Concelho de São João da Pesqueira. O objetivo geral da investigação consiste em compreender a importância do enoturismo na promoção do destino São João da Pesqueira. Por conseguinte, como objetivos específicos, o estudo pretende identificar as preferências do turista, as motivações na escolha do destino turístico, identificar um melhor conhecimento do setor, nomeadamente na área da procura, para assim possibilitar o desenvolvimento do produto, identificar e valorizar a perspetiva enoturística e identificar o impacto do enoturismo no desenvolvimento regional e local. Nas principais conclusões, é possível destacar os pontos fortes do destino, as características únicas, a paisagem, o produto (vinho), a história e a diversidade de produtores de vinhos, as novas atrações, proximidade, infraestruturas, clima, ciclo de vida do turismo e dinâmica do visitante, tendo em conta se é a primeira visita ou não. Em relação à influência do enoturismo no território, é fundamental e assume um papel crucial no Concelho, de forma transversal, uma vez que está relacionado com outras atividades, em que assume um papel de divulgação por todo o mundo, é um setor em plena expansão e que atrai imensos turistas à região, que fixa pessoas no interior, pois também dá muito trabalho a quem lá vive. Adicionalmente, o enoturismo pode ser uma alavanca na co-criação sustentável de novas experiências de turismo, de ideias inovadoras para se implementarem no concelho futuramente, que coincidem com alguma ideias já existentes em outras Regiões e Países. Relativamente ao futuro do setor do enoturismo, as estratégias passam pela valorização do destino, por apostar na diferenciação pela qualidade e pela inovação de novas propostas, como por exemplo a criação de rotas turísticas, ou a criação de novos hotéis envolvidos com a paisagem, pela diversidade vitivinícola, pela sua história. A mesma será de evolução, as regiões têm a função de valorizar a sua imagem de marca, aproveitando o enoturismo, as características do seu vinho, juntamente com a sua gastronomia, valorizando os seus recursos particulares e endógenos, e neste sentido proporcionar experiências únicas, de modo a divulgar e promover o turismo na região e por sua vez o impacto económico.The wine tourism is a market segment very much linked to rural destinations, where people can enjoy the difference and authenticity of the local products, to promote the tourism activity, stimulating, in this way, the search for a determined region. This offer typology has shown an increase in Portugal and all over the world during the last years, except in the last two years, due to the pandemic situation. It is nowadays a relevant segment of the touristic market and signifies a great potential at long and medium term. This research aims to be a contribution to deepen the knowledge about it and/or to open research horizons in this area of wine tourism, especially in the Demarcated Douro region, Municipality of São João da Pesqueira, as well as to identify a better knowledge of the sector, particularly in demand, to enable product development and also to identify the motivations in the choice of the tourism destination. This investigation focalizes the past, present, and future of the wine tourism, subject with a great incidence in the Douro Delimited Region, more exactly in the Concelho de S. João da Pesqueira. Consequently, the general objective of the investigation is to understand the importance of the wine tourism in the promotion of the destination S. João da Pesqueira. As specific objectives, the study intends to identify the tourist preferences, the motivations by the choice of the touristic destination, a better knowledge of the sector, namely in the demand area, and, in this way, to enable the product development, to identify and to value the wine touristic perspective and to identify the impact of the wine tourism in the regional and local development. By the main conclusions it is possible to put in relief the strong destination places, the unique characteristics, the landscape, the product (wine), the history and the diversity of the wine producers, the new attractions, surroundings, substructures, climate, tourism life cycle and visitor dynamics, taking in consideration if it is the first visit or not. The influence of the wine tourism in the territory is fundamental and takes a crucial part, in a transversal way, in the Concelho, because it is connected with other activities, in which it assumes a divulgation role all over the world; it is a sector in full expansion, that draws a large quantity of tourists to the region and settles a lot of people in the inland, creating, in this way, jobs to its inhabitants. In a continued way, the wine tourism can be a starting level for the maintainable co-creation of new tourism experiences and innovator ideas, to implement in the future in the Concelho. These ideas coincide already with other ideas of other regions and countries. As far as the future of the wine tourism sector is concerned, the strategies relate to the destination valuation, bet in different according to quality, new proposals, for example the creation of new touristic routes or the building of new hotels involved by the landscape, by the winegrowing diversity, by history. The regions have the function of enhancing their brand image, taking advantage of wine tourism, the characteristics of their wine, along with their gastronomy, valuing their particular and endogenous resources, and in this sense provide unique experiences, to disseminate and promote tourism in the region and in turn the economic impact

Chlormequat selective electrodes: construction, evaluation and application at FIA systems

A flow injection analysis (FIA) system having a chlormequat selective electrode is proposed. Several electrodes with poly(vinyl chloride) based membranes were constructed for this purpose. Comparative characterization suggestedthe use of membrane with chlormequat tetraphenylborate and dibutylphthalate. On a single-line FIA set-up, operating with 1x10-2 mol L-1 ionic strength and 6.3 pH, calibration curves presented slopes of 53.6±0.4mV decade-1 within 5.0x10-6 and1.0x10-3 mol L-1, andsquaredcorrelation coefficients >0.9953. The detection limit was 2.2x10-6 mol L-1 and the repeatability equal to ±0.68mV (0.7%). A dual-channel FIA manifold was therefore constructed, enabling automatic attainment of previous ionic strength andpH conditions and thus eliminating sample preparation steps. Slopes of 45.5±0.2mV decade -1 along a concentration range of 8.0x10-6 to 1.0x10-3 mol L-1 with a repeatability ±0.4mV (0.69%) were obtained. Analyses of real samples were performed, and recovery gave results ranging from 96.6 to 101.1%