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Coxsackievirus B3 Infection and Host Defence Responses Change the Metabolism of PBDELundgren, Magnus January 2009 (has links)
It has been suggested that the rising amounts of chemicals in the environment may affect host resistance and increase susceptibility to infections. Studies have also shown that infections can change the toxicity of pollutants. The aim of this thesis was to study interactions between environmental pollutant exposure in terms of polybrominated diphenyl ethers (PBDE) and a common human coxsackievirus B3 (CVB3) infection adapted to Balb/c mice. The studies focused on virus levels, cytokines, metabolising cytochrome P450 (CYP) enzymes and tissue distribution of PBDE. A novel finding was an organ-specific effect of CVB3 infection on the metabolising capacity of PBDE. The PBDE metabolising enzyme CYP2B10 was down-regulated by the CVB3 infection in the liver, up-regulated in the lungs, but not affected in the pancreas. Accordingly, CVB3 infection increased the concentration of PBDE in the livers of infected mice. However, serum levels of PBDE were not affected by the infection, indicating that serum does not reflect the actual organ exposure of PBDE in infected individuals. The change in metabolising capacity was likely mediated by infection-induced cytokines and associated effects on the nuclear factor-κB (NF-κB) pathway. PBDE drastically decreased serum levels of several cytokines and chemokines, an event that may create a slot for viruses to replicate. Accordingly, some results show that infected mice exposed to a high dose of PBDE had higher virus levels than mice exposed to a low dose. In conclusion, infected individuals showed organ-specific changes in metabolism and tissue levels of PBDE, which potentially could change the toxicity of PBDE. PBDE also seems to affect the fate of the infection. NF-κB activated pathways may mediate one possible mechanism underlying these effects. Thus, further investigations of this pathway are warranted. In addition, future studies should address how PBDE exposure affects viral replication.
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AN INVESTIGATION OF PERINATAL POLYCHLORINATED BIPHENYL EXPOSURE ON BODY COMPOSITION AND GLUCOSE HOMEOSTASISRashid, Cetewayo S 01 January 2013 (has links)
Recent advancements have uncovered environmental contributions to obesity and diabetes etiology. In fact, perinatal malnutrition resulting in low birth weight (LBW) has been shown to correlate with later life obesity and impaired glucose tolerance in aged offspring. LBW can result from a myriad of developmental perturbations including macronutrient restriction, hypoxia, maternal stress and toxin exposure.
Polychlorinated biphenyls (PCBs) are ubiquitous environmental pollutants that bioaccumulate in the food chain resulting in dietary exposure in humans. Maternal and cord blood PCB levels are inversely associated with birth weight, and recent studies indicate that perinatal exposures to PCBs contribute to gender-specific obesity development in children. PCBs have also been shown to enter breast milk resulting in direct exposure in early postnatal life. Therefore, we hypothesized that perinatal PCB exposure cause developmental blight resulting in decreased birth weight and increased adiposity and glucose intolerance with aging. We found that mice perinatally exposed to PCBs did not differ in birth weight, but exhibited sex-specific effects on adiposity. Females perinatally exposed to PCBs were significantly more obese at 7 weeks of age while male offspring exhibited no difference in fat mass but had decreased lean mass compared to controls. With aging, the differences in females dissipated while the male offspring decreased lean mass persisted. Male offspring perinatally exposed to PCBs displayed impaired glucose tolerance at 7 weeks of age but normalized over time, while the females were glucose intolerant only after 6 months of age. This impairment of glucose tolerance was not attributed to insulin resistance. These data illustrate time-dependent and sex-specific perturbations of maternal PCB exposure on offspring body composition and glucose homeostasis.
As the liver is a major facilitator in glucose homeostasis and xenobiotic detoxification, we investigated PCB-induced alterations in hepatic gene expression and found attenuated expression of glycolytic genes and increased expression of detoxifying and antioxidant genes in both PCB-exposed maternal and offspring livers. Taken together, these data demonstrate a role for perinatal pollutant exposure in the etiology of glucose intolerance. Further studies are required to elucidate the mechanisms causing sex-specific modulation of body composition and glucose intolerance.
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B grupės farmakologiškai aktyvių medžiagų liekanų kontrolė maisto grandinėje / The control of residue from pharmacologically active substances of group B in food chainPerlis, Saulius 18 June 2013 (has links)
Darbo tikslai: Analizuoti B grupės farmakologiškai aktyvių medžiagų liekanas maisto produktuose 2004-2011 metais.
Tyrimo uždaviniai:
a) surinkti ir išanalizuoti farmakologiškai aktyvių B grupės medžiagų kiekius maisto produktuose reglamentuojančius teises aktus;
b) surinkti ir išanalizuoti mokslinę literatūrą apie farmakologiškai aktyvių B grupės medžiagų patekimą į maisto produktus, jų sukeliamą žalą bei kiekius maisto produktuose;
c) išanalizuoti 2004–2011 metų farmakologiškai aktyvių B grupės medžiagų stebėsenos rezultatų ypatumus;
d) išanalizuoti 2004–2011 metais sukauptų B grupės farmakologiškai aktyvių medžiagų stebėsenos rezultatus pagal tyrimo metus ir maisto žaliavų/produktų grupes.
Magistrinį darbą sudaro šios dalys: pirma dalis – B grupės farmakologiškai aktyvios medžiagos, jų apibūdinimas ir leistini jų kiekiai maisto produktuose, antra dalis – savi tyrimai, kuriuose atlikta B grupės farmakologiškai aktyvių medžiagų 2004–2011 metų liekanų analizė . Darbe panaudotos 14 lentelių ir 4 paveikslai. Darbo apimtis 58 puslapiai.
Atlikus darbą gautos šios svarbiausios išvados:
1. Kasmet Lietuvoje vykdant farmakologiškai aktyvių medžiagų stebėseną ištiriama 3441–4319 mėginių. Nustatomi 16–41 mėginiai (0,462–0,997 %), kuriuose kontroliuojamas liekanų kiekis viršija DLK.
2. Tiriant gyvūninius maisto produktus, medžiagų liekanos, viršijančios DLK, dažniau nustatytos žuvų, kiaušinių ir pieno mėginiuose. Dažniausiai DLK viršijo aplinkos teršalų (B3 grupės) ir antibakterinių... [toliau žr. visą tekstą] / Research purpose: to analyse the residue from pharmacologically active substances of group B in food products in 2004-2011. Information and the material of the research were received from the National Food and Veterinary Institute for evaluation.
Research objectives:
a) to collect and analyse legislations regulating the amount of pharmacologically active substances of group B in food products;
b) to collect and analyse scientific literature about pharmacologically active substances of group B getting into food products, the amount and the harm caused by them;
c) to analyse the features of the results made by monitoring pharmacologically active substances of group B in 2004-2011;
d) to analyse the observed results of pharmacologically active substances of group B, according to the groups of food products and the year the research was carried out.
The Master degree dissertation contains these parts: part 1-pharmacologically active substances of group B, their description and the safe amount of them in food products, part 2- the research into the analysis of residue from pharmacologically active substances of group B made in 2004-2011. 14 tables and 4 pictures are used in the research. The thesis contains 58 pages.
The following most important conclusions were made:
1. 3441-4319 samples are examined annually by monitoring pharmacologically active substances in Lithuania. 16-41 samples, (0,462–0,997 %) which have exceeded MAC of controlled residue, are ascertained.
2. Examining... [to full text]
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Determination of Environmental Pollutants by Gas Chromatography/Mass Spectrometry with ChemometricsZhang, Mengliang January 2014 (has links)
No description available.
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Uticaj ftalata iz spoljašnje sredine na neke metaboličke poremećaje / The influence of phthalates at environmental levels on certain metabolic disordersBosić-Živanović Dragana 30 September 2015 (has links)
<p>Uvod. Ftalati su endokrini disruptori, široko se koriste kao plastifikatori, rastvarači i aditivi u mnogim potrošačkim proizvodima. Eksperimentalni podaci i humane studije sugerišu na povezanost ftalata sa gojaznošću i dijabetesom. Cilj. Utvrditi da li su i koji urinami metaboliti ftalata prisutni i da li postoje razlike u njihovim nivoima između bolesnika s tipom 2 šećeme bolesti, gojaznih i kontrolne grupe zdravih osoba; da li postoji povezanost između metabolita ftalata i gojaznosti, lipida i lipoproteina seruma, glikemije, insulinemije i insulinske rezistencije.<br />Metode. Istraživanje je obuhvatilo 305 ispitanika, podeljenih u 3 grupe: gojazni (n=104), dijabetesni bolesnici tip 2 (n=101) i zdrave osobe (n=100), oba pola. U svih ispitanika su izvršena antropometrijska merenja (BMI i obim struka), određivanje serumskih lipida (ukupni holesterol, trigliceidi, HDL i LDL holesterol), te glikemija, insulinemija i izračunat indeks insulinske rezistencije (HOMA IRI). U jutarnjem uzorku urina meren je nivo 10 ftalatnih metabolita: mono-metil ftalat (MMP), mono-etil ftalat (MEP), mono-n-butil ftalat (MnBP), mono- benzil ftalat (MBzP), mono-cikloheksil ftalat (MCHP), mono-n-propil ftalat (MPP), mono-n-amil ftalat (MnAP), mono-izo-amil ftalat (MiAP), mono- n-oktil ftalat (MOP), mono-2-etilheksil ftalat (MEHP). U odnosu na prisustvo ftalata u urinu svaka grupa je podeljena u podgrupe na one sa prisutnim ftalatima i one bez ftalata u urinu, odnosno na podgrupe MEP pozitivne, MEP negativne, MEHP pozitivne i MEHP negativne. Rezultati. Kod polovine ispitanika registrovali smo prisustvo u urinu pojedinih metabolita ftalata. Najčešći su bili MEHP i MEP. Najveća sličnost u nivou MEP-a i MEHP-a je bila između gojaznih i dijabetesnih ispitanika. U odnosu na antropometrij ske parametre uočena je pozitivna korelacija MEP-a sa BMI i obimom struka, a negativna korelacija MEHP-a sa BMI i obimom struka, ali su bile nesignifikantne. Samo kod MEHP pozitivnih kontrolne grupe uočena je statistički značajna pozitivna korelacija MEHP-a i obima struka. Utvrđena je statistički značajna negativna korelaciju MEP-a i HDL holesterola, a pozitivna korelacija MEP-a i triglicerida samo kod gojaznih. Samo u kontrolnoj grupi MEHP pozitivnih postojala je statistički značajna negativna korelacija sa HDL holesterolom. Postojala je pozitivna korelacija MEP-a i HOMA-IRI, a pozitivna korelacija MEHP-a sa glikemijom samo kod MEHP pozitivnih DM tip 2. Zaključak. Potvrđeno je da je kontaminacija ftalatima prisutna u našoj populaciji, a najčešće su prisutni MEHP i MEP, ukazujući na ekspoziciju DEHP i DEP. Indirektno smo stekli uvid da povećana izloženost DEP i DEHP može doprineti nastanku izvesnih poremećaja lipida i lipoproteina, insulinskoj rezistenciji kao i razvoju gojaznosti.</p> / <p>Introduction. Phthalates are endocrine disruptors, widely used as plasticizers, solvents and additives in a wide range of consumer products. Experimental data and human studies suggest that phthalate exposure is linked with obesity and diabetes. Aim. To determine whether urinary phthalate metabolites are present, which ones are present, whether there are differences between their levels among the patients with type 2 diabetes, obesity patients and a control group of healthy individuals; whether there is a link between phthalate metabolites and obesity, lipids, serum lipoproteins, glycemia, insulinemia and insulin resistance. Methods. The research included 305 participants divided into three groups: obesity patients (n=104), type 2 diabetes patients (n=101) and healthy individuals (n=100) in both sexes. Anthropometric measurements were taken from all participants (BMI and waist circumference), as well as measurement of serum lipids (total cholesterol, triglycerides, HDL and LDL cholesterol), glycemia, insulinemia and a calculation of insulin resistance index (HOMA IRI). The levels of ten phthalate metabolites were<br />measured in a morning sample of urine: Mono-methyl phthalate (MMP), Mono-ethyl phthalate (MEP), Mono-n-butyl phthalate (MnBP), Mono-benzyl phthalate (MBzP), Mono- cyclohexyl phthalate (MCHP), Mono-n-propyl phthalate (MPP), Mono-n-amyl phthalate (MnAP), Mono-iso-amyl phthalate (MiAP), Mono-n-octyl phthalate (MOP), Mono-2- ethylhexyl phthalate (MEHP). Regarding the presence of phthalates in urine, each group was divided into subgroups, containing phthalates and or not containing phthalates, i.e. subgroups MEP positive and MEP negative, MEHP positive and MEHP negative. Results. In a half of participants, we have registered the presence of certain phthalate metabolites in urine, most often MEHP and MEP. The highest similarity in the levels of MEHP and MEP was between obesity and diabetes participants. Regarding anthropometric measurements, positive correlation has been registered between MEP and BMI and waist circumference, while negative correlation has been registered between MEHP and BMI and waist circumference, but it was insignificant. Only in MEHP positive control group, statistically significant positive correlation between MEHP and waist circumference has been registered. Statistically significant negative correlation between MEP and HDL cholesterol has been registered, while positive correlation between MEP and triglycerides has been registered only in obesity patients group. Only in MEHP positive control group statistically significant negative correlation with HDL cholesterol has been registered. There has been a positive correlation between MEP and HOMA-IRI, while positive correlation between MEHP and glycemia has been registered only in MEHP positive DM type 2. Conclusion. It has been confirmed that our population is contaminated with phthalates, most commonly MEHP and MEP, indicating exposure to DEHP and DEP. Indirectly, we have realized that an increased exposure to DEHP and DEP can contribute to the development of certain lipid and lipoprotein disorders, insulin resistance, as well as the development of obesity.</p>
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Prospecção de fungos derivados de esponjas marinhas na degradação/descoloração de poluentes ambientais. / Prospecting fungi derived from marine sponges on degradation/decolorization of environmental pollutants.Vasconcelos, Maria Raphaella dos Santos 03 March 2015 (has links)
Diversos estudos têm demonstrado o potencial de utilização de fungos filamentosos na degradação de poluentes ambientais, no entanto, ainda são escassos. O presente trabalho teve como objetivo avaliar o potencial biotecnológico de 174 fungos filamentosos isolados a partir de seis espécies de esponjas marinhas, os quais foram submetidos ao screening em meio sólido contendo corante RBBR e guaiacol; a ensaios em meio líquido, na presença dos corantes preto sulfuroso, índigo blue e reativo black 5, na avaliação da produção das enzimas lacase, manganês peroxidase (MnP) e lignina peroxidase (LiP), utilizando siringaldazina, álcool veratrílico e o vermelho de fenol como substratos enzimáticos, respectivamente; a ensaios de degradação de pireno e benzo[a]pireno; a delineamentos experimentais; e à análise de metabólitos formado na degradação. O fungo selecionado Chaunopycnis alba CBMAI 1346 apresentou 94,54% de degradação em 35 de salinidade, evidenciando o potencial biotecnológico deste fungo em processos de degradação de poluentes ambientais em condições salinas. / Several studies have demonstrated the potential use of filamentous fungi in the degradation of environmental pollutants, however, are still scarce. This study aimed to evaluate the biotechnological potential of 174 filamentous fungi isolated from six species of marine sponges, which were subjected to screening on solid medium containing RBBR dye and guaiacol; the tests in liquid medium in the presence of sulfur black, indigo blue and reactive black 5 dyes, the evaluation of the production of enzymes laccase, manganese peroxidase (MnP) and lignin peroxidase (LiP), using syringaldazin, veratryl alcohol and phenol red as enzyme substrates, respectively; tested for degradation of pyrene and benzo [a] pyrene; the experimental designs; and analysis of metabolites formed in the degradation. The fungus selected Chaunopycnis alba CBMAI 1346 showed 94.54% of pyrene degradation in 35 salinity, highlighting the biotechnological potential of this fungus in the process of degradation of environmental pollutants in saline conditions.
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Intoxicação ambiental por chumbo em crianças de uma vila de Porto Alegre e avaliação ambiental preliminar das possíveis fontes de contaminação / Environmental lead intoxication in a neighborhood of the city of Porto Alegre and preliminary environmental investigation of the possible local sourcesFerron, Mariana Maleronka 09 June 2010 (has links)
Introdução: Intoxicação ambiental por chumbo é uma questão extensamente investigada em diversos países. No Brasil existem poucos estudos sobre o tema, em sua maioria realizada em locais com relato prévio de contaminação do meio ambiente. O objetivo deste estudo é a determinação da prevalência de intoxicação por chumbo em crianças de uma Vila na cidade de Porto Alegre sem relatos prévios de contaminação do meio ambiente por chumbo e com fatores de risco descritos na literatura. Além disso, foram avaliados fatores associados e possíveis fontes de contaminação. Metodologia: Estudo transversal de prevalência com amostra randomizada de crianças de 0 a 5 anos, em que foi medido o nível de chumbo no sangue e aplicado um questionário para avaliação de fatores associados. Posteriormente, foi realizada uma avaliação ambiental preliminar com análise direta do solo e indireta da poluição atmosférica, utilizando bioindicadores, na tentativa de averiguar possíveis fontes de contaminação. Resultados: 97 crianças participaram do estudo (83.6% da amostra selecionada), com prevalência de intoxicação por chumbo encontrada de 16.5% ([Pb] sanguíneo >= 10,0?g/dL). Reciclagem de lixo, nível educacional do pai e idade estiveram relacionados a um aumento na concentração de chumbo no sangue. Foram encontrados níveis elevados de chumbo no solo e pouca indicação de poluição atmosférica por este metal. Discussão: Encontrou-se uma prevalência significativa de intoxicação por chumbo e as possíveis fontes de contaminação nesta comunidade parecem ter relação com atividades de reciclagem de lixo. Outros estudos sobre a questão com a população infantil em geral devem ser conduzidos, bem como avaliações de possíveis fontes locais e gerais, para que se possa dimensionar corretamente essa questão no Brasil. / Introduction: Environmental lead intoxication is an extensively investigated issue in several countries. In Brazil, there are only a few studies on the theme, most of which were carried out in places with previous reports of environmental lead contamination. The objective of this study was to determine the prevalence of lead intoxication in children, from a neighborhood of the city of Porto Alegre without previous descriptions of environmental lead contamination, but with risk factors described in the literature and additionally to evaluate associated factors and possible local sources of contamination. Methodology: Cross-sectional study of prevalence with random sample of children aged 0 to 5, in which the level of lead in the blood was measured and a questionnaire was applied to evaluate associated factors. Afterwards, a preliminary environmental evaluation was carried out with direct analyses of soil and indirect analyses of air pollution, using bioindicators, in an attempt to verify possible local sources of contamination. Results: 97 children participated in the study (83.6% of the selected sample), with 16.5% of the sample showing intoxication (blood [Pb] >= 10.0 ?g/dL). Waste recycling at home, father\'s educational level and age were factors related to an increase in the concentration of lead in the blood. High levels of lead were found in the soil and there was little indication of lead deposition through atmospheric emissions. Discussion: A significant prevalence of lead intoxication was found and the possible sources of contamination in this community seem to be related to activities of waste recycling. Other studies on this matter in children in the general Brazilian population should be carried out, as well as assessments of possible sources and local risk factors.
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Desenvolvimento de procedimentos analíticos limpos e com alta sensibilidade para a determinação de espécies de interesse ambiental / Development of clean analytical procedures with high sensitivity for determination of species of environmental interestMelchert, Wanessa Roberto 28 May 2009 (has links)
Procedimentos analíticos limpos e com alta sensibilidade foram desenvolvidos para a determinação de espécies de interesse ambiental (carbaril, sulfato e cloro livre). Os procedimentos foram baseados no acoplamento de sistemas de análises em fluxo com microbombas solenoides à espectrofotometria com longo caminho óptico ou em procedimentos de extração em ponto nuvem, visando a concentração das espécies de interesse sem o emprego de solventes tóxicos. A determinação de carbaril em águas naturais foi baseada em uma dupla extração em ponto nuvem: uma etapa de clean-up para a remoção de substâncias orgânicas interferentes e outra de pré-concentração do indofenol formado na reação com a forma oxidada do p-aminofenol. Resposta linear foi observada entre 10 e 500 µg L-1, com absortividade molar aparente estimada em 4,6x105 L mol-1 cm-1. O limite de detecção foi estimado em 7 µg L-1 e coeficiente de variação em 3,4% (n = 8). Recuperações entre 91 e 99% foram estimadas para adições de carbaril em amostras de águas naturais. Uma cela simples e de baixo custo com 30 cm de caminho óptico foi construída para medidas espectrofotométricas. A cela apresenta características desejáveis como baixa atenuação do feixe de radiação e volume interno (75 µL) comparável a de uma cela convencional. O desempenho da cela foi avaliado na determinação de fosfato utilizando o método azul de molibdênio com resposta linear obtida entre 0,05 e 0,8 mg L-1 de fosfato (r = 0,999). O aumento na sensibilidade (30,4 vezes) em comparação com o obtido com uma cela de fluxo convencional de 1 cm está de acordo com o estimado pela lei de Lambert-Beer. A formação do indofenol foi também explorada para a determinação de carbaril no procedimento em fluxo com celas de 30 e 100 cm. Respostas lineares; limite de detecção e coeficiente de variação foram estimados entre 50 - 750 e 5 - 200 µg L-1; 4,0 e 1,7 µg L-1 e 2,3 e 0,7%, respectivamente, para as celas de 30 e 100 cm. O procedimento proposto foi seletivo para a determinação de carbaril, sem interferências de outros pesticidas carbamatos. O resíduo gerado foi tratado com persulfato de potássio e irradiação ultravioleta, com redução de 94% do carbono orgânico total, não sendo o resíduo degradado considerado tóxico, frente às bactérias Vibrio-fischeri. A determinação de sulfato foi baseada em medidas turbidimétricas com cela de fluxo de 1 cm, com resposta linear observada entre 20 - 200 mg L-1. Deriva de linha base não foi observada em função do fluxo pulsado gerado pelas microbombas solenoides. O limite de detecção e o coeficiente de variação (n = 20) foram estimados em 3 mg L-1 e 2,4%, respectivamente, com frequência de amostragem de 33 determinações por hora. Para aumentar a sensibilidade, uma cela de fluxo de 100 cm foi empregada e deriva de linha base foi evitada utilizando uma etapa de limpeza periódica com EDTA em meio alcalino. Resposta linear foi observada entre 7 - 16 mg L-1 com limite de detecção de 150 µg L-1 e coeficiente de variação de 3,0% (n = 20). A frequência de amostragem foi estimada em 25 determinações por hora. Resultados obtidos para amostras de águas naturais e de chuva foram concordantes a nível de confiança de 95% com o procedimento turbidimétrico em batelada. A determinação de cloro livre em águas naturais e de torneira foi baseada na reação com N,N-dietil-p-fenilenodiamina, com resposta linear entre 5 e 100 µg L-1 de hipoclorito e limite de detecção e coeficiente de variação estimados em 0,23 µg L-1 e 3,4%, respectivamente. A frequência de amostragem foi estimada em 58 determinações por hora. / Clean analytical procedures with high sensitivity for the determination of species of environmental interest (carbaryl, sulphate and chlorine) were developed. Flow systems with solenoid micropumps were coupled to long optical pathlength spectrophotometry or cloud point extraction procedures, aiming the concentration of species for determination without employing toxic solvents. Carbaryl determination in natural waters was based on a double cloud point extraction: a clean-up step for removal of interfering organic species and pre-concentration of the indophenol blue, formed in the reaction with the oxidized of p-aminophenol. Linear response was observed between 10 and 50 µg L-1, with apparent molar absortivity estimated as 4.6x105 L mol-1 cm-1. Detection limit was estimated as 7 mg L-1 and the coefficient of variation as 3.4% (n = 8). Recoveries between 91 and 99% were obtained for carbaryl spiked to natural waters. A simple and low cost flow cell with 30 cm optical path was constructed for spectrophotometric measurements. The cell shows desirable characteristics such as reduced attenuation of the radiation beam and internal volume (75 µL) comparable to conventional flow cells. The performance was evaluated by phosphate determination by the molibdenium blue method, with linear response between 0.05 and 0.8 mg L-1 of phosphate (r = 0.999). The increase in sensitivity (30.4 fold) in comparison to the obtained with a conventional 1 cm optical path flow cell agreed to theoretical value estimated by the Lambert-Beer law. The determination of carbaryl was also carried out in a flow system coupled to 30 and 100 cm optical path flow cells, also exploiting the formation of indophenol compound. Linear responses, detection limits and coefficients of variation were 50 - 750 and 5 - 200 µg L-1;4.0 and 1.7 µg L-1 and 2.3 and 0.7%, respectively, for 30 and 100 cm cells. The proposed procedure was selective for the determination of carbaryl, without interferences of other carbamate pesticides. The waste of the analytical procedure was treated with potassium persulphate and ultraviolet irradiation, with decrease of 94% of total organic carbon. The residue after treatment was not toxic for Vibrio-fischeri bacteria. Sulphate determination was based on turbidimetric measurements with 1-cm flow cell, with linear response between 20 and 200 mg L-1. Baseline drift was avoided in view of the pulsed flow related to the solenoid micropumps. The detection limit and the coefficient of variation were estimated as 3 mg L-11 and 2.4%, respectively, for a sampling rate of 33 determinations per hour. Aiming the increase in sensitivity, a 100 cm optical path flow cell was employed and baseline drift was avoided with a washing, step employing EDTA in alkaline medium. Linear response was observed between 7 - 16 mg L-1, with a detection limit of 150 µg L-1, coefficient of variation of 3.0% (n = 20) and sampling rate of 25 determinations per hour. Results obtained natural and rain for water samples agreed at 95% confidence level with the batch turbidimetric procedure. The determination of free chlorine in natural and tap waters was based on the reaction with N,N-diethyl-p-phenylenediamine, with linear response between 5 and 100 µg L-1, and detection limit and coefficient of variation estimated as 0.23 µg L-1 and 3.4%, respectively. Sampling rate was estimated as 58 determinations per hour.
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The role of EmhABC efflux pump in Pseudomonas fluorescens LP6aAdebusuyi, Abigail A Unknown Date
No description available.
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Desenvolvimento de procedimentos analíticos limpos e com alta sensibilidade para a determinação de espécies de interesse ambiental / Development of clean analytical procedures with high sensitivity for determination of species of environmental interestWanessa Roberto Melchert 28 May 2009 (has links)
Procedimentos analíticos limpos e com alta sensibilidade foram desenvolvidos para a determinação de espécies de interesse ambiental (carbaril, sulfato e cloro livre). Os procedimentos foram baseados no acoplamento de sistemas de análises em fluxo com microbombas solenoides à espectrofotometria com longo caminho óptico ou em procedimentos de extração em ponto nuvem, visando a concentração das espécies de interesse sem o emprego de solventes tóxicos. A determinação de carbaril em águas naturais foi baseada em uma dupla extração em ponto nuvem: uma etapa de clean-up para a remoção de substâncias orgânicas interferentes e outra de pré-concentração do indofenol formado na reação com a forma oxidada do p-aminofenol. Resposta linear foi observada entre 10 e 500 µg L-1, com absortividade molar aparente estimada em 4,6x105 L mol-1 cm-1. O limite de detecção foi estimado em 7 µg L-1 e coeficiente de variação em 3,4% (n = 8). Recuperações entre 91 e 99% foram estimadas para adições de carbaril em amostras de águas naturais. Uma cela simples e de baixo custo com 30 cm de caminho óptico foi construída para medidas espectrofotométricas. A cela apresenta características desejáveis como baixa atenuação do feixe de radiação e volume interno (75 µL) comparável a de uma cela convencional. O desempenho da cela foi avaliado na determinação de fosfato utilizando o método azul de molibdênio com resposta linear obtida entre 0,05 e 0,8 mg L-1 de fosfato (r = 0,999). O aumento na sensibilidade (30,4 vezes) em comparação com o obtido com uma cela de fluxo convencional de 1 cm está de acordo com o estimado pela lei de Lambert-Beer. A formação do indofenol foi também explorada para a determinação de carbaril no procedimento em fluxo com celas de 30 e 100 cm. Respostas lineares; limite de detecção e coeficiente de variação foram estimados entre 50 - 750 e 5 - 200 µg L-1; 4,0 e 1,7 µg L-1 e 2,3 e 0,7%, respectivamente, para as celas de 30 e 100 cm. O procedimento proposto foi seletivo para a determinação de carbaril, sem interferências de outros pesticidas carbamatos. O resíduo gerado foi tratado com persulfato de potássio e irradiação ultravioleta, com redução de 94% do carbono orgânico total, não sendo o resíduo degradado considerado tóxico, frente às bactérias Vibrio-fischeri. A determinação de sulfato foi baseada em medidas turbidimétricas com cela de fluxo de 1 cm, com resposta linear observada entre 20 - 200 mg L-1. Deriva de linha base não foi observada em função do fluxo pulsado gerado pelas microbombas solenoides. O limite de detecção e o coeficiente de variação (n = 20) foram estimados em 3 mg L-1 e 2,4%, respectivamente, com frequência de amostragem de 33 determinações por hora. Para aumentar a sensibilidade, uma cela de fluxo de 100 cm foi empregada e deriva de linha base foi evitada utilizando uma etapa de limpeza periódica com EDTA em meio alcalino. Resposta linear foi observada entre 7 - 16 mg L-1 com limite de detecção de 150 µg L-1 e coeficiente de variação de 3,0% (n = 20). A frequência de amostragem foi estimada em 25 determinações por hora. Resultados obtidos para amostras de águas naturais e de chuva foram concordantes a nível de confiança de 95% com o procedimento turbidimétrico em batelada. A determinação de cloro livre em águas naturais e de torneira foi baseada na reação com N,N-dietil-p-fenilenodiamina, com resposta linear entre 5 e 100 µg L-1 de hipoclorito e limite de detecção e coeficiente de variação estimados em 0,23 µg L-1 e 3,4%, respectivamente. A frequência de amostragem foi estimada em 58 determinações por hora. / Clean analytical procedures with high sensitivity for the determination of species of environmental interest (carbaryl, sulphate and chlorine) were developed. Flow systems with solenoid micropumps were coupled to long optical pathlength spectrophotometry or cloud point extraction procedures, aiming the concentration of species for determination without employing toxic solvents. Carbaryl determination in natural waters was based on a double cloud point extraction: a clean-up step for removal of interfering organic species and pre-concentration of the indophenol blue, formed in the reaction with the oxidized of p-aminophenol. Linear response was observed between 10 and 50 µg L-1, with apparent molar absortivity estimated as 4.6x105 L mol-1 cm-1. Detection limit was estimated as 7 mg L-1 and the coefficient of variation as 3.4% (n = 8). Recoveries between 91 and 99% were obtained for carbaryl spiked to natural waters. A simple and low cost flow cell with 30 cm optical path was constructed for spectrophotometric measurements. The cell shows desirable characteristics such as reduced attenuation of the radiation beam and internal volume (75 µL) comparable to conventional flow cells. The performance was evaluated by phosphate determination by the molibdenium blue method, with linear response between 0.05 and 0.8 mg L-1 of phosphate (r = 0.999). The increase in sensitivity (30.4 fold) in comparison to the obtained with a conventional 1 cm optical path flow cell agreed to theoretical value estimated by the Lambert-Beer law. The determination of carbaryl was also carried out in a flow system coupled to 30 and 100 cm optical path flow cells, also exploiting the formation of indophenol compound. Linear responses, detection limits and coefficients of variation were 50 - 750 and 5 - 200 µg L-1;4.0 and 1.7 µg L-1 and 2.3 and 0.7%, respectively, for 30 and 100 cm cells. The proposed procedure was selective for the determination of carbaryl, without interferences of other carbamate pesticides. The waste of the analytical procedure was treated with potassium persulphate and ultraviolet irradiation, with decrease of 94% of total organic carbon. The residue after treatment was not toxic for Vibrio-fischeri bacteria. Sulphate determination was based on turbidimetric measurements with 1-cm flow cell, with linear response between 20 and 200 mg L-1. Baseline drift was avoided in view of the pulsed flow related to the solenoid micropumps. The detection limit and the coefficient of variation were estimated as 3 mg L-11 and 2.4%, respectively, for a sampling rate of 33 determinations per hour. Aiming the increase in sensitivity, a 100 cm optical path flow cell was employed and baseline drift was avoided with a washing, step employing EDTA in alkaline medium. Linear response was observed between 7 - 16 mg L-1, with a detection limit of 150 µg L-1, coefficient of variation of 3.0% (n = 20) and sampling rate of 25 determinations per hour. Results obtained natural and rain for water samples agreed at 95% confidence level with the batch turbidimetric procedure. The determination of free chlorine in natural and tap waters was based on the reaction with N,N-diethyl-p-phenylenediamine, with linear response between 5 and 100 µg L-1, and detection limit and coefficient of variation estimated as 0.23 µg L-1 and 3.4%, respectively. Sampling rate was estimated as 58 determinations per hour.
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