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Arceuthobium azoricum Wiens & Hawksw. is a rare Azorean endemic epiphytic hemiparasite (mistletoe), which typically parasitizes branches of the gymnosperm Juniperus brevifolia (Hochst. ex Seub.) Antoine (Cupressaceae), which is also an Azorean endemic. Here, we describe a population of A. azoricum, on Pico Island, parasitizing Erica azorica Hochst. ex Seub. (Ericaceae), which is also an Azorean endemic. Our molecular analysis (using nuclear ribosomal internal transcribed spacer) showed no differences between individuals parasitizing Erica and Juniperus species. Moreover, a preliminary analysis showed no differences in morphological characteristics between accessions sampled from different hosts. Given that this is the first bona fide record of Arceuthobium sp. parasitizing an angiosperm, this population represents a unique host-shifting event, and its conservation is important because it may allow new insights into host recognition mechanisms in mistletoes. Immediate attention should be given to characterizing this Pico Island population using appropriate molecular methods and additional morphological analyses.
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Viscaceae , Açores , Viscaceae/genética , Viscaceae/parasitologia , Filogenia , DNA Espaçador Ribossômico/genética , Ericaceae/parasitologia , Magnoliopsida/parasitologia , Ilhas , Análise de Sequência de DNA , Doenças das Plantas/parasitologia , Dados de Sequência MolecularRESUMO
In the era of personalized medicine, pharmacovigilance faces new challenges and opportunities, demanding a shift from traditional approaches. This article delves into the evolving landscape of drug safety monitoring in the context of personalized treatments. We aim to provide a succinct reflection on the intersection of tailored therapeutic strategies and vigilant pharmacovigilance practices. We discuss the integration of pharmacogenetics in enhancing drug safety, illustrating how genetic profiling aids in predicting drug responses and adverse reactions. Emphasizing the importance of phase IV-post-marketing surveillance, we explore the limitations of pre-marketing trials and the necessity for a comprehensive approach to drug safety. The article discusses the pivotal role of pharmacogenetics in pre-exposure risk management and the redefinition of pharmacoepidemiological methods for post-exposure surveillance. We highlight the significance of integrating patient-specific genetic profiles in creating personalized medication leaflets and the use of advanced computational methods in data analysis. Additionally, we examine the ethical, privacy, and data security challenges inherent in precision medicine, emphasizing their implications for patient consent and data management.
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Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Farmacogenética , Farmacovigilância , Medicina de Precisão , Medicina de Precisão/métodos , Humanos , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/prevenção & controle , Farmacogenética/métodos , Vigilância de Produtos Comercializados/métodosRESUMO
Background: The data presented here originated from field expeditions carried out between 2017 and 2018, within the framework of Forest-Eco2 project: "Towards an Ecological and Economic valorisation of the Azorean Forest". The project aimed to quantify the ecological value of the Azorean forests, including carbon accumulation and to design and propose measures that could further enhance forest sustainability. For that, 90 forest plots were sampled on three Azores islands - São Miguel, Terceira and Pico - equally distributed into natural forest, exotic woodland and production forest. The aim of this report is to further expand knowledge on biodiversity trends enclosed in the different forest types present in the Azores, by providing a list of the occurrences of the 105 different vascular plant taxa together with a brief characterisation of their origin and life-form. New information: We provide an inventory of indigenous and non-indigenous vascular plant taxa from 90 forest stands. A total of 105 taxa were identified and registered, belonging to 60 families, 91 genera, 101 species and four subspecies. A total of 35% of the taxa were endemic, 27% native and 38% non-indigenous, including 19% of invasive taxa. Endangered and vulnerable taxa were registered, including Elaphoglossumhirtum (Sw.) C.Chr., Lactucawatsoniana Trel. and others which were considered by the authors a priority for conservation (e.g. Arceuthobiumazoricum Wiens & Hawksw., Bellisazorica Hochst. ex Seub., Saniculaazorica Guthnick ex Seub., Platantheramicrantha (Hochst. ex Seub.) Schltr.). Our records provide detailed and updated knowledge of Azorean Forest flora and highlight the role of natural forests as indigenous plant diversity hotspots and exotic woodland as a source of invasive taxa within the Archipelago.
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PREMISE: Plants endemic to oceanic archipelagos are suitable for studying evolution, being isolated on substrates of different ages. Evolution has been recent, rendering traditionally employed sequences insufficiently variable for resolving relationships. This study includes sampling in the genus Tolpis (Asteraceae) from the Azores, Madeira, and Cape Verde, and expands upon an earlier study demonstrating the efficacy of multiplexed shotgun genotyping (MSG) for resolving relationships in Canarian Tolpis. METHODS: Genomic libraries for 90 accessions of Tolpis and two from the outgroup were generated for genotyping individuals using MSG. Loci were de novo assembled with iPyrad, which clusters MSG loci within and between samples. A maximum likelihood phylogeny was generated with RAxML. Ancestral area reconstruction was inferred using R package BioGeoBEARS. RESULTS: MSG data recovered a highly resolved phylogeny from population to inter-archipelago levels. Ancestral area reconstruction provided biogeographic hypotheses for the radiation of Macaronesian Tolpis. CONCLUSIONS: Four major clades were resolved. The Madeiran endemic T. macrorhiza is sister to other Tolpis. Species from the Canaries, Cape Verdes, and the continent are sister to T. succulenta from Madeira, which has a sister subclade of Azorean populations composed of T. succulenta and T. azorica. Population-level resolution suggests unrecognized taxa on several archipelagos. Ancestral reconstruction suggests initial dispersal from the continent to Madeira, with dispersal to the Azores, then dispersal from Madeira to the Canary Islands, with both subsequent dispersal to the Cape Verdes and back-dispersal to the continent. Single-island radiations and inter-island dispersal are implicated in divergence in Macaronesian Tolpis.
Assuntos
Asteraceae , Asteraceae/genética , Açores , Genótipo , FilogeniaRESUMO
Assessment of forest ecosystems and their services is seen as a key action for the advancement of biodiversity objectives, and to inform the development and implementation of related policies and planning. The Azorean forest is important for timber production, the protection of soil and water resources, and for its recreational and aesthetic value. However, its role in carbon accumulation has not been fully addressed. We assessed plant diversity, forest structure and carbon stocks in a gradient of three forest types (Natural Forest-NF; Exotic Woodland-EW and Production Forest-PF) in three of the Azores islands. We used biodiversity indices and found that NF harbored the highest plant diversity levels and PF the lowest. Diversity levels were lower for structural than for taxonomic data, particularly for PF. The highest tree carbon stock was found at EW in one of the islands, while PF consistently exhibited relatively high tree carbon stocks in the three islands. The largest soil carbon stocks were found at EW, while leaf litter carbon stocks were higher at PF. We concluded that NF play a fundamental role as plant diversity hotspots but have lower relevance as carbon stocks what might be associated with montane environmental conditions. PFs provide economic assets and act as carbon sinks, while EWs play a major role as carbon sinks in soil, but also at tree level in the oldest forests.
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Fibroepithelial polyps are benign lesions that may appear in the vulvovaginal region. They usually occur in women of reproductive age and tend to grow up to 5 cm, but there are some rare cases in which they grow up to 20 cm. We report a case of a 22-year-old woman in the third trimester of her first pregnancy with spontaneous bleeding from a pedunculated mass measuring 15 cm in the widest diameter on the right side of the vulva. Features of this case are discussed as well as its implications, especially regarding the decision of labour. Due to the big size of the mass and its propensity to bleed, we decided to perform an elective caesarean section as well as its excision.
Assuntos
Neoplasias Fibroepiteliais/diagnóstico , Pólipos/diagnóstico , Complicações Neoplásicas na Gravidez/diagnóstico , Hemorragia Uterina/etiologia , Neoplasias Vulvares/diagnóstico , Cesárea , Feminino , Humanos , Recém-Nascido , Neoplasias Fibroepiteliais/complicações , Neoplasias Fibroepiteliais/patologia , Neoplasias Fibroepiteliais/cirurgia , Pólipos/complicações , Pólipos/patologia , Pólipos/cirurgia , Gravidez , Complicações Neoplásicas na Gravidez/patologia , Complicações Neoplásicas na Gravidez/cirurgia , Terceiro Trimestre da Gravidez , Resultado do Tratamento , Hemorragia Uterina/cirurgia , Vulva/patologia , Vulva/cirurgia , Neoplasias Vulvares/complicações , Neoplasias Vulvares/patologia , Neoplasias Vulvares/cirurgia , Adulto JovemRESUMO
Genome-wide genotyping and Bayesian inference method (BORICE) were employed to estimate outcrossing rates and paternity in two small plant populations of Tolpis succulenta (Asteraceae) on Graciosa island in the Azores. These two known extant populations of T. succulenta on Graciosa have recently evolved self-compatibility. Despite the expectation that selfing would occur at an appreciable rate (self-incompatible populations of the same species show low but nonzero selfing), high outcrossing was found in progeny arrays from maternal plants in both populations. This is inconsistent with an immediate transition to high selfing following the breakdown of a genetic incompatibility system. This finding is surprising given the small population sizes and the recent colonization of an island from self-incompatible colonists of T. succulenta from another island in the Azores, and a potential paucity of pollinators, all factors selecting for selfing through reproductive assurance. The self-compatible lineage(s) likely have high inbreeding depression (ID) that effectively halts the evolution of increased selfing, but this remains to be determined. Like their progeny, all maternal plants in both populations are fully outbred, which is consistent with but not proof of high ID. High multiple paternity was found in both populations, which may be due in part to the abundant pollinators observed during the flowering season.
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Fatty acids have been used as biomarkers of the microbial community composition of soils and they are usually separated and quantified by gas-chromatography coupled to a flame ionization detector (GC-FID). The aim of this study was to develop, validate and apply a methodology based on gas chromatography coupled to optical fiber detection (GC-OF) for screening five fatty acids used as indicators of fungal and bacterial communities in urban soils. The performance of the GC-OF methodology (optical fiber detector at 1,550 nm) was evaluated by comparison with the GC-FID methodology and it was found that they were comparable in terms of linear range, detection limit and analytical errors. Besides these similar analytical characteristics, the GC-OF is much cheaper than the GC-FID methodology. Different concentrations were determined for each fatty acid indicator which in turn varied significantly between the soil samples analyzed from Lisbon ornamental gardens. Additionally, the GC-OF showed a great potential as alternative for determination of eleven or more fatty acids in urban soils.
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Cromatografia Gasosa/métodos , Ácidos Graxos/análise , Consórcios Microbianos , Microbiologia do Solo , Solo/análise , Biomarcadores/análise , Cidades , Fibras Ópticas , Solo/químicaRESUMO
A new methodology for the assessment of thiocyanate (SCN(-)) is proposed based on optical fiber (OF) detection coupled to a liquid chromatography system (LC). The developed methodology showed an adequate performance for the analysis of SCN(-) comparable to a high performance liquid chromatography with UV detector (HPLC-UV) methodology: a detection limit of 3 µg L(-1), a linear range from 4 to 400 µg L(-1), and an analytical time of less than 6 min. The OF based methodology was of compact design and easy operation. This simple system has the potential to be used as a sensing approach for SCN(-) in seawater.
Assuntos
Monitoramento Ambiental/instrumentação , Fibras Ópticas , Água do Mar/química , Tiocianatos/análise , Poluentes Químicos da Água/análise , Monitoramento Ambiental/métodos , Poluição Química da Água/estatística & dados numéricosRESUMO
Breath analysis constitutes a promising tool in clinical and analytical fields due to its high potential for non-invasive diagnostics of metabolic disorders and monitoring of disease status. An optical fiber (OF) sensor has been developed for determination of volatile organic compounds (ethane, pentane, heptane, octane, decane, benzene, toluene and styrene) in human breath for clinical diagnosis. The analytical system developed showed a high performance for breath analysis, inferred for the analytical signal intensity and stability, linear range, and detection limits ranging from 0.8 pmol L(-1), for heptane, and to 9.5 pmol L(-1), for decane. The OF sensor also showed advantageous features of near real-time response and low instrumentation costs, besides showing an analytical performance equivalent to the breath analysis by gas chromatography-mass spectrometry (GC-MS), used as the reference method.
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Testes Respiratórios , Técnicas de Laboratório Clínico , Compostos Orgânicos Voláteis/análise , Biomarcadores/análise , Biomarcadores/química , Testes Respiratórios/instrumentação , Testes Respiratórios/métodos , Tecnologia de Fibra Óptica , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Doenças Metabólicas/diagnóstico , Padrões de Referência , Compostos Orgânicos Voláteis/químicaRESUMO
Pulp and paper mills generate pollutants associated to their effluents depending upon the type of process, type of the wood materials, process technology applied, management practices, internal recirculation of the effluent for recovery, the amount of water used in the industrial process and type of secondary treatment. This study is the first that reports a simultaneous evaluation of the effects of tertiary treatments by fungi (Rhizopus oryzae and Pleurotus sajor caju), by enzyme (laccase) and by an oxidation process (photo-Fenton) on individual phenols (vanillin, guaiacol, phloroglucinol, vanillic acid and syringic acid) of a Eucalyptus globulus bleached kraft pulp and paper mill final effluent after secondary treatment (BKPME). The tertiary treatments were applied on BKPME samples and in BKPME samples supplemented with extra concentration of each phenol. Tertiary treatments by Rhizopus oryzae and photo-Fenton oxidation were able of complete removal (100%) of phenols on BKPME samples whereas P. sajor caju and laccase were able of 60-85% removal. On BKPME samples with added concentration of each phenol, photo-Fenton was the only treatment capable of total phenols removal (100%), which suggests a great potential for its application.
Assuntos
Resíduos Industriais , Lacase/metabolismo , Papel , Fenóis/química , Fenóis/metabolismo , Pleurotus/metabolismo , Rhizopus/metabolismo , Eliminação de Resíduos Líquidos/métodos , Benzaldeídos/química , Benzaldeídos/metabolismo , Biodegradação Ambiental , Eucalyptus/química , Ácido Gálico/análogos & derivados , Ácido Gálico/química , Ácido Gálico/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Guaiacol/química , Guaiacol/metabolismo , Oxirredução , Floroglucinol/química , Floroglucinol/metabolismo , Extração em Fase Sólida , Ácido Vanílico/química , Ácido Vanílico/metabolismoRESUMO
The determination of fatty acids (FA) has been extensively used as a sensitive and reproducible parameter for characterizing the soil microorganism communities and to detect various environmental stresses. The aim of this study was to assess the variability of FA in urban soils, in an attempt to use it as a differentiator of urban soil usage. FA were extracted from soils of five different usages (ornamental gardens, ornamental gardens/roadsides, roadsides, parks and urban agricultural areas) in three Portuguese cities and FA concentration was determined by gas chromatography coupled to mass spectrometry (GC-MS). A total of fifteen FA have been detected and the concentration of each FA, in general, decreased in the following order: Lisbon>Estarreja>Viseu, for all the usages of urban soil. According to soil microbial indicators, the concentration of Gram-negative bacteria was lower than the concentration of Gram-positive bacteria, which together were, in turn, higher than the concentration of fungi for all the usages of urban soil and city. This study assessed the FA profiles of urban soils, which differ as a function of soil usage. The FA profile also is at the source of the inference that stress in soil microorganism communities results from the different urban environment in each city.
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Monitoramento Ambiental/métodos , Ácidos Graxos/análise , Solo/química , Bactérias/crescimento & desenvolvimento , Biomassa , Cidades , Contagem de Colônia Microbiana , Fungos/crescimento & desenvolvimento , Microbiologia do Solo , Poluentes do Solo/análiseRESUMO
In recent years, there has been an increasing interest in the application of optical fiber sensors for in situ monitoring of chemical pollutants, including volatile organic compounds, regarding air quality assurance. In order to enhance the usefulness and applicability of this methodology to environmental analysis, a proper study of the analytical signal and an adequate calibration model are required. This contribution is focused on the model for optical fiber sensors calibration, discussing some problems associated with the estimates of the figures of merit of these analytical systems. We also suggest and discuss a calibration model based on a cumulative symmetric double sigmoidal (SDS) function, as a suitable and general alternative to the more limited and classical linear calibration model.
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BACKGROUND, AIM AND SCOPE: Pulp and paper mills generate a plethora of pollutants depending upon the type of pulping process. Efforts to mitigate the environmental impact of such effluents have been made by developing more effective biological treatment systems in terms of biochemical oxygen demand, chemical oxygen demand, colour and lignin content. This study is the first that reports an evaluation of the effects of a tertiary treatment by fungi (Pleurotus sajor caju, Trametes versicolor and Phanerochaete chrysosporium and Rhizopus oryzae) on individual organic compounds of a Eucalyptus globulus bleached kraft pulp and paper mill final effluent after secondary treatment (final effluent). MATERIAL AND METHODS: The tertiary treatment with P. sajor caju, T. versicolor and P. chrysosporium and R. oryzae was performed in batch reactors, which were inoculated with separate fungi species and monitored throughout the incubation period. Samples from effluent after secondary and after tertiary treatment with fungi were analysed for both absorbance and organic compounds. The samples were extracted for organic compounds using solid-phase extraction (SPE) and analysed by gas chromatography-mass spectrometry (GC/MS). The efficiencies of the SPE procedure was evaluated by recovery tests. RESULTS: A total of 38 compounds (carboxylic acids, fatty alcohols, phenolic compounds and sterols) were identified and quantified in the E. globulus bleached kraft pulp mill final effluent after secondary treatment. Recoveries from the extraction procedure were between 98.2% and 99.9%. The four fungi species showed an adequate capacity to remove organic compounds and colour. Tertiary treatment with R. oryzae was able to remove 99% of organic compounds and to reduce absorbance on 47% (270 nm) and 74% (465 nm). P. sajor caju, T. versicolor and P. chrysosporium were able to remove 97%, 92% and 99% of organic compounds, respectively, and reduce 18% (270 nm) to 77% (465 nm), 39% (270 nm) to 58% (465 nm) and 31% (270 nm) to 10% (465 nm) of absorbance, respectively. DISCUSSION: The wide variety of organic compounds found in the final effluent must be due to the degradation of E. globulus wood in pulp and paper mill. The concentrations of organic compounds in the final effluent of E. globulus bleached kraft pulp mill were in residual levels maybe due to the secondary treatment. The recovery tests showed the effectiveness of the extraction procedure, and no losses of analyte were suspected in the analytical determinations. Lignin derivatives such as vanilic acid, syringic acid, guaiacol, syringol and phloroglucinol were totally removed by R. oryzae, but the 47% absorbance reduction obtained at 270 nm suggests that these species were not able to complete degradation of lignin macromolecular compounds. CONCLUSIONS: The organic compounds (carboxylic acids, fatty alcohols, phenolic compounds and sterols) were removed more efficiently by tertiary treatment with R. oryzae or P. chrysosporium, followed by P. sajor caju and T. versicolor. Regarding the removal of both colour and organic compounds, the tertiary treatment with R. oryzae was the most efficient. RECOMMENDATIONS AND PERSPECTIVES: In order to reduce the deleterious impacts of paper mill effluents, efforts have been made to develop more effective advanced tertiary treatments. This study may serve as a basis of characterisation, in terms of organic compounds of E. globulus bleached kraft pulp mill final effluent after secondary treatment and as an effort to understand the effects of tertiary treatments with fungi on low concentrations of organic compounds from biological secondary treatment.
Assuntos
Fungos/metabolismo , Resíduos Industriais/análise , Papel , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/metabolismo , Biodegradação Ambiental , Reatores Biológicos/microbiologia , Ácidos Carboxílicos/análise , Ácidos Carboxílicos/metabolismo , Eucalyptus/microbiologia , Álcoois Graxos/análise , Álcoois Graxos/metabolismo , Água Doce/análise , Phanerochaete/metabolismo , Fenóis/análise , Fenóis/metabolismo , Pleurotus/metabolismo , Rhizopus/metabolismo , Esteróis/análise , Esteróis/metabolismo , Trametes/metabolismo , Poluentes Químicos da Água/análiseRESUMO
An optical fiber biosensor has been developed for the determination of catecholamines (dopamine, norepinephrine and epinephrine) based on the recognition capacity of the enzyme laccase. In this study, a glass tube constituted by a fused silica fiber coated with a film of polystyrene/divinylbenzene resin (PS/DVB) was used for catecholamines separation. Firstly, the analyzer was tested for calibration and its analytical performance for catecholamines detection was compared with a classical analytical method, namely high performance liquid chromatography-electrochemical detector (HPLC-ED). The developed analytical device shows a high potential for catecholamines quantification with a detection limit of 2.1, 2.6 and 3.4 pg mL(-1) for dopamine, norepinephrine and epinephrine, respectively. The analytical sensitivity, inferred from the slope of the calibration curves established for a range of concentrations between 5 and 125 pg mL(-1), was found to be 0.344, 0.252 and 0.140 dB/pg mL(-1) for dopamine, norepinephrine and epinephrine, respectively. Furthermore, catecholamines speciation with the PS/DVB fiber was completely achieved in 3 min. The analytical performance of the reported sensor was also evaluated and found adequate for catecholamines determination in human urine and plasma samples.
Assuntos
Técnicas Biossensoriais/métodos , Cromatografia Líquida de Alta Pressão/métodos , Dopamina/isolamento & purificação , Epinefrina/isolamento & purificação , Norepinefrina/isolamento & purificação , Fibras Ópticas , Análise de Variância , Técnicas Biossensoriais/instrumentação , Calibragem , Dopamina/sangue , Dopamina/urina , Eletroquímica , Epinefrina/sangue , Epinefrina/urina , Humanos , Norepinefrina/sangue , Norepinefrina/urina , Poliestirenos/químicaRESUMO
An analytical method based on separation by high performance liquid chromatography (HPLC) and detection by optical fiber (OF) coated with an enzyme (laccase), has been developed for separation and quantification of catecholamines, namely epinephrine, dopamine and norepinephrine. The application of OF as a detector in this analytical system relies on the variation of the reflected optical power detected when the catecholamines eluted from the HPLC column act as the substrate of the laccase immobilized on a tip of a single-mode OF. The developed method shows a high linearity in a range between 5 and 125 pg/mL and detection limits of 3.5, 2.9 and 3.3 pg/mL for epinephrine, dopamine and norepinephrine, respectively. The analytical performance of the proposed method was compared with a classical analytical method, namely high performance liquid chromatography-electrochemical detector (HPLC-ED) regarding catecholamines detection, showing great analytical advantages such as low cost of equipment. Additionally, the proposed method was applied to catecholamines determination in actual samples of plasma and human urine.
Assuntos
Catecolaminas/sangue , Catecolaminas/urina , Cromatografia Líquida de Alta Pressão/instrumentação , Cromatografia Líquida de Alta Pressão/métodos , Enzimas Imobilizadas/química , Lacase/química , Fibras Ópticas , Enzimas Imobilizadas/metabolismo , Desenho de Equipamento , Feminino , Humanos , Lacase/metabolismo , Modelos Lineares , Masculino , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
An analytical methodology based on a field-effect transistor detector using carbon nanotubes (NTFET) coupled to a gas chromatograph has been developed for the speciation of the following aromatic compounds: benzene, toluene, ethylbenzene, m-xylene, p-xylene and o-xylene (BTEX). This methodology combines the proven separation capability of gas chromatography (GC) with the potential for detection of a NTFET. The developed analyzer shows a high and stable analytical response upon repeated analysis of BTEX during 4 weeks, with detection limit less than 4mug/L. The GC-NTFET system also shows a great suitability for actual monitoring of indoor atmospheres and no significant difference was observed between the results obtained by the developed analyzer and a more classical analytical methodology, namely gas chromatography-flame ionization detection (GC-FID).
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Poluentes Atmosféricos/análise , Derivados de Benzeno/análise , Benzeno/análise , Cromatografia Gasosa/instrumentação , Nanotubos de Carbono , Poluentes Ocupacionais do Ar/análise , Hidrocarbonetos Aromáticos/análise , Microquímica/métodos , Portugal , Transistores EletrônicosRESUMO
An analytical method based on optical fiber (OF) detection has been developed for monitoring nitrous oxide (N(2)O) in workplace environments. The analyzer was firstly tested for calibration and then its analytical performance for N(2)O detection compared with solid phase microextraction-gas chromatography-mass spectrometry, an already validated method for determination of N(2)O. The response of the OF analyzer was linear from 0.20 to 1.80 ppb, and the detection limit was less than 0.03 ppb. After some laboratory tests, the developed analytical system was applied to air monitoring at a confined industrial environment showing a suitable compact design and a high analytical performance for N(2)O monitoring, both in situ and in a real-time mode.
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Poluentes Ocupacionais do Ar/análise , Monitoramento Ambiental/métodos , Óxido Nitroso/análise , Exposição Ocupacional/análise , Fibras Ópticas , Calibragem , Monitoramento Ambiental/instrumentação , Cromatografia Gasosa-Espectrometria de Massas , Microextração em Fase SólidaRESUMO
A portable optical fibre sensor has been developed for remote monitoring of benzene, toluene, ethylbenzene, p-xylene, m-xylene and o-xylene (BTEX). Firstly, the analyser was tested for calibration and its analytical performance for BTEX monitoring compared with a more classical analytical method, namely gas chromatography coupled to a flame ionization detector (GC-FID). The developed remote sensor shows several analytical advantages such as, high analytical sensitivity and accuracy, good linearity and stability of the analytical signal and short analytical time. Secondly, the optical fibre based sensor was applied to air monitoring for detection and quantification of BTEX in a confined industrial environment. The analytical signal measurement was performed by wireless at 20 m of distance from the local of analysis. Besides, the reported sensor showed a high degree of portability, compact design and high analytical performance for remote BTEX monitoring, in situ and in real-time.
Assuntos
Poluentes Ocupacionais do Ar/análise , Derivados de Benzeno/análise , Benzeno/análise , Cromatografia Gasosa , Fibras Ópticas , Tolueno/análise , Xilenos/análiseRESUMO
Leachates derived from landfill constitute a serious environmental concern as a variety of pollutants can leak from the landfill sites with potential risk of groundwater pollution. Benzene, toluene, ethylbenzene, p-xylene, m-xylene and o-xylene (BTEX) are pollutants widely found in landfill leachate and therefore the development of analytical methodologies which can provide a rapid and simple measurement of these compounds is of great interest. This paper reports an optical fibre (OF) sensor for environmental applications, namely for BTEX determination in landfill leachate samples.Firstly the analytical signal of the developed OF sensor was evaluated regarding some operational variables affecting the deposition of the sensitive siloxane film (type of siloxane cladding, deposition technique, number of cycles for deposition, cure temperature and experimental conditions for stabilization) in order to achieve a high sensitivity of the analytical system. Secondly, the OF based sensor was applied to landfill leachate samples for detection and quantification of BTEX. The obtained results have been compared to the ones obtained by the method based on a gas chromatography-flame ionization detector (GC-FID).The developed OF methodology showed notable analytical advantages, such as high analytical sensitivity and accuracy, good linearity and stability of the analytical signal, and detection limits in the order of a few nanograms (raging from 0.9 to 1.4 ng) for BTEX determination.