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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
271

Effets sanitaires de l'exposition aux sous-produits de chloration de l'eau / Health effects of exposure to disinfection by-products

Costet-Deiber, Nathalie 19 September 2013 (has links)
Contexte. La chloration est le traitement le plus utilisé pour désinfecter l’eau distribuée à la population. Lors du traitement, des sous-produits de chloration (SPCs) se forment par réaction de la matière organique naturelle présente dans l’eau avec le chlore. Les produits les plus présents sont les trihalométhanes (THMs), les acides haloacétiques (HAAs). Des études toxicologiques (animales et in vitro) ont montré la génotoxicité et/ou carcinogénicité et la reprotoxicité de certains SPCs. Nous avons mené deux études évaluant les effets sur la santé humaine de l’exposition aux SPCs, dans le domaine du cancer et de la reproduction. Association entre exposition aux THMs et risque de cancer de la vessie : une analyse poolée de 3 études cas-témoins européennes. Cette analyse a inclus 2381 cas et 3086 témoins issus de 3 études cas-témoins (France, Espagne, Finlande). L’exposition environnementale aux SPCs a été mesurée par la concentration en THMs estimée rétrospectivement dans les réseaux de distribution d’eau au cours des 40 années de la fenêtre d’exposition. Les usages de l’eau connus sont l’ingestion, les douches et les bains, la fréquentation de piscine (étude espagnole seulement). Une relation croissante a été observée entre le niveau environnemental de THMs, la durée d’exposition à une eau de surface chlorée et le risque de cancer de la vessie, chez les hommes uniquement. Aucune association n’a été observée avec l’exposition via l’ingestion d’eau du robinet. L’exposition via les douches, les bains et la piscine est apparue liée au risque de cancer de la vessie. Trois études cas-témoins nord-américaines ont été intégrées dans une méta-régression. Aucune spécificité européenne de la relation dose-réponse n’a été mise en évidence. Une relation dose-réponse globale incluant 4351 cas et 7055 témoins a été estimée. Association entre exposition aux SPCs et risque de prématurité et de retard de croissance intra-utérin (RCIU). Cette étude est issue de la cohorte bretonne Pélagie (3400 femmes enceintes recrutées en début de grossesse entre 2002 et 2006). L’exposition pendant la grossesse a été mesurée à l’aide de 2 indicateurs : la concentration en THMs de l’eau distribuée dans les réseaux et le dosage d’un biomarqueur urinaire (acide trichloroacétique) pour un sous-échantillon de femmes (étude cas-témoins nichée). Les niveaux dans les réseaux proviennent de la base de données réglementaire SISE-Eaux. Les usages de l’eau du robinet par les femmes pendant la grossesse ont été collectés par questionnaire (quantité d’eau du robinet bue, fréquentation de la piscine, fréquence et durée des douches et des bains). Notre étude suggère une association entre l’exposition prénatale aux SPCs et le risque de RCIU. Aucune association n’est observée avec le risque de prématurité. / Background. Chlorine is the most widely used disinfectant for drinking water treatment. During treatment process, the natural organic matter present in water reacts with chlorine to form disinfection by-products (DBPs), such as trihalomethanes (THMs) and haloacetic acids (HAAs), the most occurring ones. Several identified DBPs were recognized carcinogens or fetotoxic in animals. We conducted two epidemiological studies to assess the health effects of human exposure to DBPs regarding cancer and reproduction. Association between THM exposure and the risk of bladder cancer: a pooled analysis of 3 European case-control studies. The study included 2381 cases and 3086 controls from 3 case-control studies (France, Finland, Spain). Environmental exposure to SPCs was measured by THM concentrations in water distribution systems, retrospectively estimated through the 40-year exposure window. Information about water uses (tap water ingestion, showers and baths, swimming-pool attendance) was available. An increased risk of bladder cancer was observed, in men only, with increasing THM concentrations in water systems and duration of exposure to chlorinated surface water. No association was observed with exposure through tap water ingestion. Exposure through showers, baths and swimming in pools (available in Spanish study only) was associated with an increased risk of bladder cancer. Three North-American case-control studies were joined to the three European ones into a meta-regression. No specific dose-response relationship was identified for European studies. A global dose-response relationship was consequently estimated, including 4351 cases and 7055 controls. Association between DBP exposure and the risk of preterm birth and Intra-Uterine Growth Retardation (IUGR). This study was conducted within the PELAGIE cohort (3400 pregnant women included in early pregnancy, in Brittany, France, between 2002 and 2006). Exposure during pregnancy was measured by 2 indicators: THM concentrations in water distribution systems and a biomarker of HAA ingestion, the level of trichloroacetic acid in maternal urine at inclusion (in a nested case-control study). The regulatory database SISE-Eaux was used to estimate THMs concentrations in the water distribution systems. Water uses during pregnancy (ingested tap water, swimming-pool attendance, showers and bath frequencies and duration) were collected with questionnaires. Our results suggest an association between prenatal exposure to DBPs (THMs and HAAs) and the risk of IUGR. No association was found with the risk of preterm birth.
272

Compostos bioativos no pinhão manso e na mamona: potencial de utilização de seus subprodutos na alimentação de ovinos / Bioactive compounds in jatropha curcas and castor beans: potential of utilization of by-products in sheep feeding

Alline Mariá Schumann 26 May 2017 (has links)
A produção de biodiesel vem crescendo ao longo dos anos e com ela o interesse por matérias-primas alternativas para produção. O pinhão manso e a mamona são consideradas promissoras pelo elevado teor de óleo nas sementes e potencial de utilização dos seus subprodutos na alimentação animal. Entretanto, o uso desses subprodutos é limitado devido à presença de ésteres de forbol (EF) no pinhão manso e de ricina na mamona. Nesse sentido, objetivou-se mensurar o teor de EF e ricina nos subprodutos do pinhão manso e da mamona, respectivamente, assim como avaliar o potencial de utilização desses subprodutos na alimentação de ovinos. O estudo foi desenvolvido em três experimentos. No experimento I os EF foram quantificados nas sementes e frações da semente de pinhão manso, assim como nas tortas e óleos após prensagem a frio das respectivas sementes e albumens. Os resultados mostraram que as tortas possuem perfil nutricional interessante para a dieta de ruminantes e que os EF foram concentrados no óleo após a prensagem, sugerindo que tortas com menor teor de óleo residual apresentem menores concentrações de EF. No experimento II, torta de mamona (TM) e torta de pinhão manso (TPM), destoxificada ou não, foram avaliadas em dois níveis de substituição ao farelo soja, 25 e 35% TPM e 25% e 50% TM, sobre os parâmetros de degradabilidade e fermentação ruminal in vitro. Após 24 horas de incubação foi observado que inclusão da TM e TPM, destoxificada ou não, não afetou a produção de gases total, a produção de N-NH3 e ácidos graxos de cadeia curta total (AGCC), indicando que a fermentação ruminal não foi afetada. Contudo, houve redução na concentração dos isoácidos com a inclusão de 50% de TM destoxificada, 35% de TPM e 25% de TPM destoxificada. A produção de metano foi reduzida com a inclusão de 35% de TPM não destoxificada, indicando que a presença de EF pode ter alterado a população de bactérias metanogênicas no liquido ruminal. No experimento III foi avaliada a substituição parcial do farelo de soja pela TM destoxificada sobre a eficiência de utilização dos nutrientes, microbiota ruminal e emissão de metano entérico de ovinos alimentados com esse subproduto. Os animais que receberam a dieta com TM destoxificada consumiram em média 0,59 mg de ricina kg-1 de peso corporal dia-1 e não apresentaram sintomas clínicos de intoxicação sequer alterações nos níveis séricos de enzimas relacionadas a função hepática e renal. A inclusão da TM destoxificada não influenciou no consumo dos animais, porém reduziu a digestibilidade dos nutrientes. A inclusão da TM destoxificada não alterou a síntese microbiana no rúmen, balanço de nitrogênio, parâmetros de fermentação ruminal e população microbiana em relação ao tratamento controle, com exceção do acetato, que aumentou com a inclusão da TM destoxificada, mas não refletiu sobre a emissão de metano ruminal. Apesar do potencial de substituição da torta de mamona destoxificada, a redução na digestibilidade aparente de alguns nutrientes podem refletir na redução do desempenho e aumento da produção de metano por kg de produto animal / Biodiesel production has been growing over the years and with it the interest for alternative raw materials for production. Jatropha and castor beans are considered to be promising because of the high oil content in seeds and potential of utilization of its by-products in animal feeding. However, these by-products usage is limited due to the presence of phorbol esters (PE) in jatropha and ricin in castor bean. In this sense, the objective was to measure PE and ricin content in by-products of jatropha and castor bean, respectively, as well as to evaluate the potential of utilization of these by-products in sheep feeding. The study was developed in three experiments. In the experiment I, PEs were quantified in seeds and fractions of jatropha seed, as well as in cakes and oils after cold-pressing of respective seeds and albumens. The results showed that the cakes have an interesting nutritional profile for ruminant diet and PEs were concentrated in the oil after pressing, suggesting that cakes with lower residual oil content showed lower PE concentrations. In the experiment II, castor cake (CC) and jatropha cake (JC), detoxified or not, were evaluated at two substitution levels of soybean meal, 25 and 35% of JC and 25% and 50% of CC, on the degradability and ruminal fermentation parameters in vitro. After 24 hours of incubation, it was observed that inclusion of CC and JC, detoxified or not, did not affect the total gas production, N-NH3 and total short chain fatty acids (SCFAs) production, indicating that ruminal fermentation was not affected. However, there was a reduction in isoacid concentration with the inclusion of 50% of detoxified CC, 35% of CC and 25% of detoxified JC. Methane production was reduced with the inclusion of 35% of non-detoxified JC, indicating that the presence of PE may have changed methanogenic bacteria population in the ruminal fluid. In the experiment III was evaluated the partial substitution of soybean meal by detoxified CC on the nutrient use efficiency, ruminal microbiota and enteric methane emission from sheep fed with this by-product. Animals that received diet with detoxified CC consumed on average 0.59 mg of ricin kg-1 body weight day-1 and did not showed clinical symptoms of intoxication even changes in serum levels of enzymes related to liver and renal function The inclusion of detoxified CC did not influence animal consumption, but it reduced the digestibility of nutrients. The inclusion of detoxified CC did not change rumen microbiota synthesis, nitrogen balance, ruminal fermentation parameters and microbial population in relation to the control treatment, with exception of acetate, which increased with detoxified CC inclusion, but did not reflect on ruminal methane emission. Despite the potential of replacement of detoxified castor cake, the reduction in apparent digestibility of some nutrients may reflect in performance reduction and increase in methane production per kg of animal product
273

Substituição parcial do milho pela casca de soja na alimentação de cordeiros da raça Santa Inês em confinamento / Partial replacement of corn by soybean hulls fed to feedlot lambs

Evandro Maia Ferreira 12 June 2008 (has links)
Foram realizados dois experimentos com o objetivo de avaliar o efeito da substituição parcial do milho pela casca de soja (CS) sobre o desempenho, o comportamento ingestivo, as características da carcaça, a digestibilidade aparente dos nutrientes, o balanço de nitrogênio, os parâmetros ruminais e sangüíneos de cordeiros da raça Santa Inês. O tratamento controle (CS0) foi uma ração contendo 70% de milho (% da MS), sendo o milho substituído em 15%, 30% e 45% pela CS, constituindo os tratamentos CS0, CS15, CS30 e CS45, respectivamente. As rações experimentais foram isonitrogenadas (19,12 ± 0,60% de PB), contendo 90% de concentrado e 10% de feno de \"coastcross\" (Cynodon sp.). No Experimento I (digestibilidade, balanço de nitrogênio, parâmetros ruminais e sangüíneos): foram utilizados 16 cordeiros, canulados no rúmen com peso médio inicial de 44,3 ± 5 kg e aproximadamente 6 meses de idade, distribuídos em delineamento experimental de blocos completos casualizados. O consumo de MS, MO, FDN, FDA e PB em kg/dia e g/kg de PC0,75, bem como o consumo de NDT em kg/dia, de ED em Mcal/dia aumentaram linearmente (P < 0,05) com a inclusão de CS. A retenção de nitrogênio reduziu linearmente (P < 0,05) e a concentração de propionato no fluido ruminal apresentou efeito quadrático (P < 0,05), tendo-se máxima concentração no tratamento CS15. Enquanto que, o consumo de EE g/kg de PC0,75, os valores de NDT em % da MS, a concentração de ED em Mcal/kg de MS, os coeficientes de digestibilidade aparente da MS, CNF, PB e EE, e a concentração total dos AGCC e de amônia no fluido ruminal não foram afetados pelos tratamentos. No experimento II (desempenho, características de carcaça e comportamento ingestivo): foram utilizados 64 cordeiros com peso inicial de 18,3 ± 2,8 kg e idade de 69 ± 5 dias, distribuídos em delineamento experimental de blocos completos casualizados, com dois animais por baia e 8 baias por tratamento. O GMD, as características da carcaça e os tempos gastos com as atividades de ingestão (min/g de MS), ruminação (min/dia e min/g de MS) e mastigação (min/dia) não foram afetados pelos tratamentos. O consumo de MS e de FDN, a CA, e os tempos gastos com ruminação (min/g de FDN) e mastigação (min/g de MS) aumentaram linearmente (P < 0,05) com a inclusão de CS. A inclusão de CS na ração, em substituição parcial ao milho, aumentou o consumo dos nutrientes e de energia digestível, e melhorou o pH ruminal, sem afetar o GMD e as características da carcaça dos cordeiros. Entretanto, reduziu a retenção de nitrogênio e piorou a CA. / Two experiments were conducted to evaluate the effects of partial replacement of corn by soybean hulls (SH) on performance, carcass characteristics, ingestive behavior, apparent digestibility of nutrients, nitrogen balance and ruminal and blood parameters of Santa Ines lambs. The control treatment (SH0) was a diet containing 70% of corn on a DM basis. On the others diets corn was replaced by SH at 15, 30 and 45%, corresponding to the experimental treatments SH0, SH15, SH30 and SH45, respectively. All diets were isonitrogen (19.12 ± 0.60% of CP), containing 90% of concentrate and 10% \"coastcross\" hay (Cynodon sp.). In Trial 1 (apparent digestibility of nutrients, nitrogen balance, ruminal and blood parameters), sixteen Santa Ines ram lambs (BW 44.0 ± 5.0 kg and 6 months old) were allotted individually in suspended metabolism crates, assigned to a complete randomized block design. DM, OM, NDF, ADF and CP intake (kg/day and g/kg of BW0,75), and also TDN intake (kg/day), DE intake (kg/day), increased linearly (P < 0.05) with SH addition. Nitrogen retention decreased linearly (P < 0.05) and propionate concentration (mM) showed a quadratic response (P < 0.05). There was no effect on EE intake (g/kg of BW0,75), TDN values (% of DM), DE concentration (Mcal/kg of DM), apparent digestibility of DM, NFC, CP, EE, and ruminal ammonia and total SCFA concentrations. In Trial 2 (performance, carcass characteristics and ingestive behavior), sixty-four Santa Ines lambs (BW 18,3 ± 2,8 kg and 69 ± 5 days old) were penned (2/pen) and used in a complete randomized block with four treatments and eight replicates. ADG, carcass characteristics and the times expended in ingestion (min/g of DM), rumination (min/day and min/g of DM) and chewing (min/day) activities there was no effect treatments. DMI and NDF intake, FC and the times expended in rumination (min/g of NDF) and chewing (min/g of DM) increased linearly (P < 0.05) with SH addition. SH inclusion in the diet at replacing corn, increased nutrients and DE intake and improved ruminal pH. with no detrimental effect on ADG and carcass characteristics. However, decreased nitrogen retention and worsened the FC.
274

Subprodutos de acerola como fontes de compostos fenólicos em leites fermentados probióticos / Acerola by-products as sources of phenolic compounds in probiotics fermented milks.

Tatyane Lopes de Freitas 30 November 2017 (has links)
Subprodutos de frutas são rotineiramente descartados pelas indústrias. Porém, são ricos em compostos bioativos, podendo ser utilizados como ingredientes em produtos funcionais, promovendo a saúde e minimizando o impacto ambiental. O objetivo deste trabalho foi estudar o potencial funcional de subprodutos desidratados de acerola e de laranja, como fontes de compostos fenólicos, e desenvolver leites fermentados probióticos adicionados deste resíduo, avaliando suas características físico-químicas durante o armazenamento sob refrigeração (28 dias; 4 ± 1 °C), bem como o impacto das condições gastrointestinais sobre os flavonoides e as cepas probióticas. Os subprodutos foram obtidos em indústrias de processamento de frutas do estado de São Paulo, e foram realizadas as seguintes análises para caracterizá-los: composição centesimal, teores de vitamina C, minerais, fibras alimentares, compostos fenólicos totais e proantocianidinas, capacidade antioxidante in vitro e perfil cromatográfico de flavonoides (CLAE). Foram elaboradas quatro formulações de leites fermentados: F0 (controle), sem adição de resíduo de acerola (RA); F2, com 2% de RA; F5, com 5% de RA; F10, com 10% de RA. Adicionou-se a cultura probiótica ABT-4 nos produtos, constituída de duas cepas probióticas: Bifidobacterium animalis subsp lactis Bb-12 e Lactobacillus acidophilus La-5, além da cultura starter Streptococcus thermophilus. As seguintes análises foram realizadas com as formulações de leites fermentados, durante o armazenamento sob refrigeração (28 dias, 4 ± 1 °C): composição centesimal, pH, acidez, viabilidade dos microrganismos, teor de compostos fenólicos totais (CF), cor e textura instrumentais. Além disso, os leites fermentados foram submetidos a condições gastrointestinais simuladas in vitro, para avaliação do impacto na viabilidade das cepas probióticas e nos compostos fenólicos. O RA mostrou-se excelente fonte de vitamina C (605 mg/100 g b.u.), além de apresentar melhor capacidade antioxidante in vitro do que o RL. Proantocianidinas foram encontradas apenas no RA, na concentração de 617 &#181;g EC/g b.s. O teor de compostos fenólicos totais do RA (3240 &#181;g EAG/100 g b.s.) foi 3,6 vezes maior que o do RL. Os principais compostos fenólicos encontrados no RA foram: derivados de quercetina, procianidina B1, rutina, e derivados de caempferol. No RL, foram identificados: naringenina, sinensetina, homorientina, isovitexina e derivados de ácido clorogênico. Os subprodutos estudados apresentaram elevados teores de fibras totais (acima de 60%) e proteínas totais (RA: 10,4%; RL: 9,9%), além de reduzido teor de lipídeos totais (RA: 1,6%; RL: 2,6%). Os principais minerais identificados em ambos os resíduos foram: potássio, magnésio, cálcio e fósforo. Quanto às quatro formulações de leites fermentados, estas apresentaram baixo teor de lipídeos totais (menor que 1%), e o teor de proteínas totais variou entre 3,9 e 5,1 g/100 g, estando de acordo com a legislação vigente para este tipo de produto. O pH das formulações F0 (controle) e F2 manteve-se estável significativamente (p > 0,05) ao longo do período de armazenamento sob refrigeração (28 dias; 4 ± 1 °C), e das outras formulações sofreu pequena queda, mesmo assim mantendo-se acima de 4,5. A acidez das formulações, que variou entre 0,92 a 1,28 mg de ácido lático/g, aumentou entre os dias 1 e 14 de armazenamento, depois se manteve até o final da vida de prateleira. O RA não interferiu de maneira negativa nas populações de microrganismos analisadas durante o armazenamento, já que as formulações F2, F5 e F10 mantiveram suas populações em torno de 8 log UFC/g. Quanto ao teor de CF, as amostras diferiram significativamente entre si (p < 0,05), sendo que F0 apresentou teor em torno de 5 vezes inferior a F10 (21,13 e 101,13 &#181;g EAG/100 g, respectivamente, no dia 1). A cor dos produtos se manteve até o final da vida de prateleira, e diferiram significativamente (p < 0,05) entre si. O RA influenciou pouco nos parâmetros de textura dos leites fermentados, mas a formulação controle foi a única que perdeu adesividade. Após a fase gástrica da digestão simulada in vitro, no 7° dia de armazenamento, as populações de bactérias probióticas diminuíram drasticamente (quedas em torno de 3 a 5 log UFC/g), e após a fase entérica não foram detectadas contagens. Por outro lado, os flavonoides encontrados nos leites fermentados adicionados de RA aumentaram em torno de 2 a 5 vezes, após a fase gástrica, mantendo-se ou sofrendo pequena queda após fase entérica. Estes resultados mostram que o pó de subprodutos de acerola é um valioso ingrediente a ser utilizado em alimentos funcionais, pois é rico em vitamina C, fibras e compostos fenólicos, agregando valor nutricional, além de servir como antioxidante natural. Seus flavonoides parecem ser altamente resistentes aos ácidos e sais da digestão, podendo, assim, exercer efeitos positivos sobre a saúde. / Fruits by-products are routinely discarded by industries. However, they are rich in bioactive compounds, and can be used as ingredients in functional foods, promoting health and minimizing environmental impact. The objective of this study was to investigate the functional potential of acerola and orange dehydrated by-products, as sources of phenolic compounds, and to develop probiotic fermented milks suplemented with this residues, evaluating its physico-chemical characteristics during refrigerated storage (28 days, 4 ± 1 °C), as well as the impact of gastrointestinal conditions on flavonoids and probiotic strains. The by-products were obtained from fruit processing industries of São Paulo, and the following analyzes were performed to characterize them: contents of moisture, ash, lipids, proteins, vitamin C, minerals, dietary fibers, total phenolic compounds and proanthocyanidins, antioxidant capacity in vitro and flavonoids chromatographic profile (HPLC). Were elaborated four formulations of fermented milks: F0 (control), without addition of acerola residue (AR); F2, with 2% AR; F5, with 5% AR; F10, with 10% AR. Was used the probiotic culture ABT-4, composed of two probiotic strains, Bifidobacterium animalis subsp lactis Bb-12 and Lactobacillus acidophilus La-5, in addition to the starter culture Streptococcus thermophilus. During the refrigerated storage (28 days, 4 ± 1 °C), the following analyzes were performed with the fermented milks: contents of moisture, ash, lipids and proteins, pH, acidity, viability of microorganisms, total phenolic compounds (PC), instrumental color and texture. In addition, the fermented milks were submitted to in vitro simulated gastrointestinal conditions to evaluate the impact on the viability of probiotic strains and phenolic compounds. AR presented excellent content of vitamin C (605 mg/100 g), in addition to presenting better antioxidant capacity in vitro than orange residue (OR). Proanthocyanidins were found only in AR (617 &#181;g CE/g). The PC content of AR (3240 &#181;g GAE/100 g) was 3.6 higher than in OR. The phenolic compounds identified in AR were quercetin-3-rhamnoside, rutin and others quercetin derivatives, procyanidin B1 and kaempferol derivatives. In OR, were identified naringenin, sinensetin, homorientin, isovitexin and chlorogenic acid derivatives. The by-products studied showed high total fibers content (above 60%) and total proteins (AR: 10.4%, OR: 9.9%), as well as reduced total lipids content (AR: 1.6%; OR: 2.6%). Both residues showed high levels of potassium, calcium, magnesium and phosphorus. The four formulations of fermented milks presented low total lipids content (below 1%), and the total proteins content ranged from 3.9 to 5.1 g/100 g, being in agreement with the legislation. The pH of F0 (control) and F2 formulations remained stable (p > 0.05) throughout the refrigerated storage period (28 days, 4 ± 1 °C), and the other formulations showed a small decreased, even thus remaining above 4.5. The acidity of the formulations, ranging from 0.92 to 1.28 mg of lactic acid/g, increased between days 1 and 14 of storage, then remained until the end of shelf life. The AR did not negatively interfere in the populations of microorganisms analyzed during storage, since the formulations F2, F5 and F10 maintained their populations around 8 log CFU/g. Regarding PC content, the samples differed significantly (p < 0.05), with F0 being about 5 lower than F10 (21.13 and 101.13 &#181;g GAE/100 g, respectively, in the day 1). The instrumental color of the products remained until the end of shelf life, and differed significantly (p < 0.05) from each other. The AR influenced a little in the texture parameters of the fermented milks, but the control formulation was the only one that lost adhesiveness. After the gastric phase of the simulated digestion in vitro, on the 7th day of storage, the populations of probiotic bacteria decreased dramatically (of 3 to 5 log CFU/g), and after the enteric phase no colonies were detected. On the other hand, the flavonoids found in the fermented milks that were suplemented with AR increased from 2 to 5 times, after the gastric phase, maintaining or suffering small decreased after enteric phase. These results show that acerola by-products powder is a valuable ingredient to be used in functional foods because it is rich in vitamin C, dietary fibers and phenolic compounds, adding nutritional value, and serving as a natural antioxidant. Its flavonoids appear to be highly resistant to the acids and salts of digestion and can thus have positive effects on health.
275

Avaliação da remoção de diclofenaco e formação de subprodutos em tratamento de água / Evaluation of the removal of diclofenac and formation of by-products in water treatment

Eliane Sloboda Rigobello 14 May 2012 (has links)
A presença de resíduos de fármacos em águas superficiais e de abastecimento público tem preocupado a comunidade científica devido principalmente à sua persistência na água e aos efeitos adversos causados à comunidade aquática e aos possíveis riscos à saúde humana. Dentre os fármacos comumente identificados em águas de abastecimento público, encontram-se os anti-inflamatórios, como o diclofenaco (DCF), um dos fármacos mais consumidos no Brasil e no mundo. Nesse contexto, o presente trabalho, teve como objetivo principal estudar a eficiência das etapas de tratamento de água em ciclo completo (coagulação, floculação, sedimentação, filtração em areia e desinfecção com cloro) com e sem pré-oxidação com cloro e com dióxido de cloro e adsorção em carvão ativado granular (CAG) na remoção de DCF. Também foram determinados os trialometanos (THM) e identificados os principais subprodutos do DCF formados na oxidação com cloro e dióxido de cloro. Para a determinação do DCF nas amostras de água antes e após as etapas de tratamento de água foram desenvolvidos e validados métodos analíticos de extração em fase sólida (SPE) e cromatográfico por cromatografia líquida de alta eficiência (HPLC) com detecção no ultravioleta (UV). A validação do método foi feita de acordo com a resolução n&ordm; 899 de 2003 da Agência Nacional de Vigilância Sanitária (ANVISA), considerando os requisitos para métodos bioanalíticos. Os procedimentos analíticos empregados foram efetivos e confiáveis para a identificação e quantificação do DCF nas amostras de água antes e após os processos de tratamento de água. Os ensaios de tratamento de água foram feitos em equipamento de reatores estáticos (jarteste) e filtros de escala laboratorial empregando-se água de poço artesiano não clorada preparada com substâncias húmicas aquáticas (SHA) para conferir cor verdadeira de 20 uH, caulinita para conferir turbidez de 70 uT e fortificada com 1 mg L-1 de DCF. Os resultados indicaram que as etapas de coagulação com sulfato de alumínio, floculação, sedimentação e filtração em areia não removeram o DCF. Nas etapas de préoxidação com cloro e dióxido de cloro e de pós-cloração houve remoção parcial do DCF, porém verificou-se a formação de subprodutos provenientes da oxidação do DCF. Dentre os THM, foi quantificado apenas o clorofórmio na etapa de pré-oxidação com cloro. Em geral, os resultados indicaram que o dióxido de cloro foi mais eficiente na redução do DCF e formou menos subprodutos. Entretanto, o tratamento em ciclo completo seguido da adsorção em CAG foi eficiente na remoção de DCF, com remoção maior que 99,7%. Os subprodutos formados na oxidação com cloro e dióxido identificados por cromatografia líquida acoplada a espectrometria de massas em série (LC-MS/MS) consistiram na descaboxilação/hidroxilação e substituição aromática de átomos de hidrogênio por cloro. Os subprodutos identificados na oxidação com cloro apresentaram as seguintes fórmulas moleculares: C14H11</subCl2NO3, C13H10Cl3N e C14H10Cl3NO2. Com o dióxido de cloro foi identificado o subproduto de fórmula molecular igual a C14H11Cl2NO3. / The presence of pharmaceutical residues in surface waters and in drinking water supply has concerned the scientific community, mainly in which regards their persistence in water, adverse effects on the aquatic community and possible risks to human health. Antiinflammatory drugs, as diclofenac (DCF), are among those drugs commonly identified in drinking water supply. In this context, the main objective of this study was to assess the efficiency of the different stages of the conventional drinking water treatment (coagulation, flocculation, sedimentation, sand filtration and chlorine disinfection) with and without preoxidation with chlorine and chlorine dioxide and adsorption on granular activated carbon (GAC) in the removal of DCF. The trihalomethanes (THMs) were also determined and the main by-products of DCF formed by oxidation with chlorine dioxide and chlorine were identified. For the DCF determination in water samples before and after water treatment stages analytical methods of solid phase extraction (SPE) and chromatographic method by high performance liquid chromatography (HPLC) with detection in the ultraviolet (UV) were developed and validated. The method validation was based on Resolution n&ordm; 899 of the 2003 of the Brazilian National Health Surveillance Agency (ANVISA), considering the requirements for bioanalytical methods. The analytical procedures used were effective and reliable for the identification and quantification of DCF in the water samples before and after the water treatment stages. The water treatment tests were carried out in jar test equipment and filters on laboratory scale employing non chlorinated water of artesian well prepared with aquatic humic substances (AHS) to yield 20 uH true color, kaolin turbidity of 70 NTU and DCF concentration of 1 mg L-1. The results indicated that the stages of coagulation with aluminum sulphate, flocculation, sedimentation and filtration sand did not remove DCF. In the stages of pre-oxidation with chlorine and chlorine dioxide and chlorine disinfection the DCF was partially removed, however by-products were formed from the DCF oxidation. Among the THMs, only chloroform was quantified in the pre-oxidation with chlorine. In general, the results showed that chlorine dioxide was more effective to reduce the DCF and fewer by-products were formed. Nevertheless, the complete cycle treatment followed by GAC adsorption was effective to remove DCF (&gt; 99.7%. removal). The by-products of the oxidation of DCF with chlorine and chlorine dioxide identified by liquid chromatography coupled tandem mass spectrometry (LC-MS/MS) consisted in the descaboxylation/hydroxylation and aromatic substitution of hydrogen atoms by chlorine. The compounds identified in the oxidation with chlorine showed the following molecular formulas: C14H11</subCl2NO3, C13H10Cl3N e C14H10Cl3NO2. The by-product identified using chlorine dioxide was C14H11Cl2NO3.
276

Fontes nitrogenadas com diferentes taxas de degradação ruminal na alimentação de ovinos / Dietary nitrogen sources with differents ruminal degradability rates in sheep nutrition

Mendes, Clayton Quirino 01 February 2010 (has links)
Foram realizados três experimentos com o objetivo de determinar os efeitos do aumento da PDR da ração por meio do uso de fontes nitrogenadas com diferentes taxas de degradação ruminal. Exp. 1: 28 cordeiros da raça Santa Inês foram utilizados para avaliação do desempenho, características da carcaça e da carne e parâmetros sanguíneos. Além disso, foi avaliada a capacidade do SRNS em predizer o CMS e o GMD dos animais. O farelo de soja foi substituído pela uréia nos teores de 0,7%; 1,4% e 2,1% da MS. Não houve alteração no CMS e nos parâmetros de carcaça e da carne avaliados. Entretanto, o GMD e o peso final dos animais reduziu linearmente na medida que a uréia substituiu o farelo de soja. Por outro lado, a conversão alimentar e a concentração de nitrogênio uréico plasmático apresentou aumento linear com a adição de uréia nas rações. O modelo SRNS apresentou tendência de subestimar o CMS e superstimar o GMD. Exp. 2: 16 cordeiros da raça Santa Inês, canulados no rúmen, foram mantidos em gaiolas metálicas para ensaio de metabolismo e alimentados com as mesmas rações utilizadas no Exp. 1. Não houve diferença no consumo e nos coeficientes de digestibilidade aparente da MS, MO, PB e FDN, bem como no pH ruminal. Houve efeito quadrático para a concentração de acetato e para a produção total de AGCC, enquanto que a concentração de amônia ruminal aumentou linearmente com adição de uréia nas rações. O uso da uréia não alterou o metabolismo do nitrogênio, a excreção urinária de derivados de purina, a produção de nitrogênio microbiano e a eficiência de síntese microbiana. Embora tenha reduzido o GMD em 14,3%, a uréia pode ser utilizada com fonte exclusiva de nitrogênio na alimentação de cordeiros confinados. Exp. 3: 48 ovelhas da raça Santa Inês em lactação foram utilizadas para determinar os efeitos do uso de fontes nitrogenadas com diferentes taxas de degradação ruminal. O farelo de soja, a protenose mais uréia, o refinazil mais uréia ou a uréia foram utilizados como fontes de N, resultando em rações contendo 9,88; 10,4; 12,0 ou 13,4% de PDR, respectivamente. O CMS foi maior, a produção de leite e de leite corrigido para gordura tendeu ser maior (P<0,10) e o teor de gordura do leite foi menor para a ração contendo o farelo de soja. A produção diária de proteína foi maior e o teor de uréia no leite foi menor para as rações contendo o farelo de soja ou a protenose mais uréia como fontes nitrogenadas. A menor eficiência de utilização do N está associada com a alta taxa de degradação da proteína no rúmen, uma vez que as rações contendo 12,0 ou 13,4% de PDR resultaram na redução da produção de proteína do leite, maior concentração de uréia no leite, perda de peso e de condição corporal dos animais. Além disso, o aumento da PDR da ração com a substituição total da proteína verdadeira pela uréia comprometeu o consumo de matéria seca e a produção de ovelhas em lactação. / Three trials were conducted to evaluate the effects of increasing dietary RDP through the use of nitrogen sources with differents rumen degration rates. Trial 1: Twenty-eight Santa Ines ram lambs were used to evaluate the effects of replacing soybean meal by urea in high grain diets on performance, carcass characteristics, meat quality and blood parameters. In addition, were assessed the ability of SRNS to predict dry matter intake and average daily gain of lambs. Soybean meal in control diet was replaced by urea at 0.7; 1.4 e 2.1% on a DM basis. There were no differences among experimental diets for dry matter intake, carcass characteristics and meat parameters. However, average daily gain and final weight decreased linearly as the urea replaced soybean meal. Likewise, feed conversion and plasma urea nitrogen concentration increased linearly with the addition of urea in experimental diets. The SRNS model tended to underestimate dry matter intake and overestimate the average daily gain. Trial 2: Sixteen ruminally cannulated Santa Ines ram lambs were placed in metabolism crates and fed the same TMR used in Trial 1. There was no effect on DM intake, apparent digestibility of dry matter, organic matter, crude protein and neutral detergent fiber, as well as, ruminal pH. Acetate concentration and total short-chain fatty acids concentration showed a quadratic response, while ruminal ammonia concentration increased linearly with urea inclusion to the diet. The nitrogen metabolism, urinary excretion of purine derivatives, microbial nitrogen production and microbial protein synthesis was not influenced with the replacement of soybean meal by urea. Although decreased average daily gain in 14.3%, urea can be used as an exclusive N source in high grain diets fed to feedlot lambs. Trial 3: Forty-eight Santa Ines lactating ewes were used to determine the effects of diets containing N sources with different ruminal degradability. Soybean meal, corn gluten meal plus urea, corn gluten feed plus urea or urea were used as N source, resulting in diets with 9.88, 10.4, 12.0 and 13.4 % of RDP, respectively. Dry matter intake was higher, milk production and fat-corrected milk tended to be higher (P<0.10) and milk fat content was lower for soybean meal diet. Daily milk protein production was higher, and milk urea nitrogen content was lower for diets containing soybean meal or corn gluten meal plus urea as N source. The lower N efficiency was associated with high protein ruminal degradation rate, once the diets containing 12.0 or 13.4% RDP resulted in reduced milk protein production, higher milk urea concentration and loss of weight and body condition score. Furthermore, a higher RDP with the total replacement of the true protein by urea affected dry matter intake and milk production of lactating ewes.
277

VALORIZZAZIONE DI SOTTOPRODOTTI AGRO-ALIMENTARI PER LA PRODUZIONE DI COMPOSTI AD ALTO VALORE AGGIUNTO

AMENDOLA, DANILA 21 February 2013 (has links)
Questa tesi di dottorato ha riguardato il recupero di composti ad alto valore aggiunto dai sottoprodotti agro-alimentari e il loro utilizzo in campo alimentare. In particolare, si è studiato il frazionamento lignocellulosico di raspi d’uva e residui di potatura di melo per ottenere emicellulosa, cellulosa, lignina e antiossidanti attraverso processi di auto-idrolisi e organosolv, investigando successivamente l’influenza di sei cultivar sul frazionamento lignocellulosico dei raspi. Un processo composto da quattro fasi (trattamento di lavaggio seguito da un’idrolisi acida, un’idrolisi basica e, infine, una decolorazione basica) è stato applicato su raspi di uva rossa (Barbera, Pinot Noir, Nebbiolo) e bianca (Müller, Chardonnay and Moscato). I raspi sono stati confrontati in termini di composizione chimica della materia prima (umidità, ceneri, minerali, lipidi, fibre, proteine zuccheri liberi) e di frazioni recuperate ( lavaggio, liquors acidi e basici e residui di cellulosa finali). Si è inoltre studiato l’influenza varietale sull’estrazione di antiossidanti da vinacce di Barbera, Pinot Noir and Nebbiolo, i diversi estratti sono stati confrontati per il loro profilo fenolico e per la loro capacità antiossidante. Infine, un estratto liofilizzato di vinacce di Barbera è stato utilizzato per migliorare la shelf-life di una pasta di nocciole valutando l’ossidazione cinetica. / This thesis has focused on the recovery of high value compounds from agri-food by-products and their use in food. In particular, we studied the lignocellulosic fractionation of grape stalks and apple tree pruning for the recovery of hemicelluloses, cellulose, lignin and antioxidants through processes of auto-hydrolysis and organosolv, investigating subsequently the influence of six grape cultivar,on the lignocellulosic fractionation of grape-stalks. A four-step process (a washing treatment followed by an acid hydrolysis, a basic hydrolysis and, finally, a basic bleaching) was applied to stalks obtained from six different red (Barbera, Pinot Noir, Nebbiolo) and white (Müller, Chardonnay and Moscato) grape cultivars. The different stalks were compared in terms of chemical composition of raw material (moisture, ash, minerals, lipids, fiber, proteins, free sugars) and of the recovered fractions (washing, acid and basic liquors and final cellulose residues). We also studied the influence of variety on the antioxidants extraction from Barbera, Pinot Noir and Nebbiolo grape marc. The different extracts were compared in terms of phenolic profile and antioxidant capacity. Finally, a freeze-dried extract from Barbera grape marc was used to improve the shelf-life of hazelnut paste evaluating the oxidation kinetics.
278

Formulaciones de nuevos morteros y cementos especiales basadas en suproductos de magnesio

Formosa Mitjans, Joan 03 December 2012 (has links)
Aquesta tesi conté una recerca amb possibilitat de generar una patent, que afecta a "Magnesitas Navarras S.A" / En la presente tesis doctoral se evalúa el potencial de algunos subproductos de magnesio empleados para la formulación de diferentes materiales de construcción y su utilización en diferentes soluciones constructivas. En este sentido, el uso de subproductos industriales para el desarrollo de materiales de construcción potencia criterios de sostenibilidad y beneficios medioambientales asociados a la reutilización de materiales secundarios y a la disminución de actividades extractivas de recursos naturales. La memoria de la presente tesis doctoral se ha estructurado siguiendo el mismo eje conductor desarrollado en la parte experimental del trabajo. Así, ésta incluye una primera parte en la que se detalla el estado del arte referente a los materiales de construcción, así como las soluciones constructivas propuestas. Estas soluciones son, por un lado, el desarrollo de morteros destinados a la protección pasiva frente al fuego (PPF) y, por otro, la formulación de cementos químicos de fosfato (CBPC) de magnesio como material reparador de estructuras de hormigón. Como primer punto del trabajo experimental se ha estudiado y caracterizado exhaustivamente los diferentes subproductos empleados, tanto físico-química como morfológicamente. Esta caracterización preliminar es de gran importancia en el desarrollo de la investigación, dado que, al tratarse de subproductos industriales, no se conocen de antemano las características y las propiedades que éstos presentan, siendo su conocimiento de vital importancia para la correcta consecución de los objetivos establecidos. En el desarrollo experimental de la primera de las soluciones constructivas propuestas, se ha empleado dos subproductos de magnesio [Low-Grade Magnesium Hydroxide (LG-MH) y Low-Grade Magnesium Carbonate (LG-MC)] en la formulación de morteros PPF, utilizando en este caso el cemento Portland convencional como material aglomerante. Ambos subproductos industriales descomponen térmicamente mediante procesos endotérmicos que cubren un amplio rango de temperaturas, retardando así el tiempo necesario para alcanzar una determinada temperatura. En este caso, se han formulado morteros empleando como áridos distintos porcentajes de ambos subproductos, dando lugar a un material con buenas propiedades térmicas y mecánicas, factible de ser utilizado como un mortero PPF. Sin embargo, su utilización como mortero revoco puede verse limitada por la elevada densidad de los áridos utilizados. En este supuesto, puede mejorarse su aplicabilidad añadiendo a los morteros formulados con subproductos de magnesio un árido ligero, como la vermiculita, sin que ello perjudique al resto de propiedades evaluadas. En la consecución de la segunda solución constructiva propuesta, se evalúa la viabilidad del uso como materia prima de otro subproducto de magnesio [Low-Grade Magnesium Oxide (LG-MgO)], en este caso para el desarrollo de cementos químicos de fosfato (CBPC) de magnesio. A tal efecto, se han determinado las propiedades mecánicas de distintas dosificaciones, así como el efecto de un aditivo retardante del fraguado, el ácido bórico (HB), descrito en la bibliografía como retardante de fraguado que permite mejorar la trabajabilidad de los CBPC. Este estudio se ha realizado empleando una herramienta estadística, el diseño de experimentos (DoE), con la finalidad de obtener modelos matemáticos que justifiquen las interacciones entre los distintos componentes de la mezcla y su efecto sobre las propiedades mecánicas y el tiempo de fraguado. Asimismo, el uso del DoE ha de permitir reducir el número de experimentos y establecer el mejor rango de dosificaciones en función de las características deseadas, dando lugar a una formulación adecuada para su utilización en las soluciones constructivas objeto de estudio. Destacar que el uso de LG-MgO en la formulación de CBPC introduce fases inertes no-reactivas contenidas en el propio subproducto, lo que implica que los CBPC desarrollados puedan considerarse como morteros. A partir de los resultados obtenidos se ha seleccionado un pequeño grupo de formulaciones con porcentajes adecuados para evaluar su potencial empleo en el desarrollo de morteros reparadores de estructuras de hormigón. Con este propósito, se han realizado ensayos de adhesión sobre distintos sustratos (hormigón o terrazo) y se ha determinado algunas propiedades requeridas para su uso en la solución constructiva propuesta. La presente tesis doctoral pretende confirmar la viabilidad tecnológica para los distintos campos de aplicación que se han postulado. Sin embargo, no es un objetivo de este estudio el desarrollar un producto final que pueda ser comercializado, sino demostrar su viabilidad gracias al know-how adquirido durante los años de esta investigación, y sentar así las bases para futuros estudios en el desarrollo de materiales de construcción empleando estos subproductos. / The present thesis is focused in the assessment of some magnesium by-products and their potential reutilization for the formulation of different materials for several construction applications. Therefore, the use of industrial by-products for the development of construction materials highlights the sustainability criteria along with the environmental benefits associated with the reutilization of secondary materials whilst diminishing the extractive activities of natural resources. This thesis has been structured following the same pattern for the experimental work. Thus, the first part details the state of the art in what construction materials concerns as well as some of the construction solutions suggested. These solutions are, on the one hand, included in the development of mortars for passive fire protection (PFP) and, on the other hand, in the formulation of chemical bonded phosphate ceramics (CBPC) as a repairing material for concrete structures. The first part presents an exhaustive chemical, physical and morphological characterization of the by-products used. This preliminary characterization is of great importance in the development of the research because of the industrial origin of these by-products. In the first part of the experimental section, the first of the solutions proposed used two types of magnesium by-products [Low-Grade Magnesium Hydroxide (LG-MH) and Low-Grade Magnesium Carbonate (LG-MC)] in the formulation of PFP mortars, using conventional Portland cement as a binder. Both industrial by-products thermally decompose through endothermic processes in a wide range of temperatures, delaying the time needed to achieve a selected temperature. In this case, the mortars were formulated by using different percentages of both by-products as aggregates, obtaining a material with good thermal and mechanical properties and therefore feasible to be used as a PFP mortar. However, its utilization as a sprayed mortar can be limited because of the high density of the aggregates used. In this sense, the practical applicability can be improved by adding a lightweight aggregate such as vermiculite, without diminishing the rest of the assessed properties. Subsequently, in the second part of the experimental section, the viability of another magnesium by-product [Low-Grade Magnesium Oxide (LG-MgO)] is evaluated. In this case, for the development of chemical bonded phosphate ceramics (CBPC). The assessment was made by determining the mechanical properties of different dosages as well as by measuring the effect of a setting-time retarder additive, boric acid (HB), described in the literature as a good additive for this purpose while improving workability as well. This study has been realized by means of a statistical method, the design of experiments (DoE), with the purpose of obtain mathematical models that justify the interactions between different components in the mix and their effect in the mechanical properties and the setting-time. Moreover, the use of DoE enables the reduction in the number of experiments and establishes the best range of dosages as a function of the desired characteristics, giving an optimized formulation to be used in the construction solutions that are object of study. It has to be emphasize that the use of LG-MgO in the formulation of CBPC introduces inert phases that are contained in the by-product itself and that are non-reactive, which implies that the CBPC obtained could be considered as mortars. From the results obtained, a small group of formulations with different percentages was selected to be studied with respect their potential as repairing mortars in concrete structures. Following this objective, adhesion tests were performed over different substrates (concrete or terrazzo) and some of the properties required for their use were determined. The main objective of this thesis is to confirm the technological viability for the different fields of application postulated. However, it is not the main purpose to develop a final product able to be commercialized but to prove the viability by means of the know-how acquired during the years of this research and setting up the base for future studies in the development of construction materials using these by-products.
279

Optimization of Solid Phase Microextraction for Determination of Disinfection By-products in Water

Riazi Kermani, Farhad January 2012 (has links)
A new technique for sample preparation and trace analysis of organic pollutants in water using mixed-phase thin film (MPTF) devices, combined with direct thermal desorption, cold trapping, gas chromatography-mass spectrometry (GC-MS) is presented for the first time. Two novel analytical devices, Carboxen/polydimethylsiloxane (CAR/PDMS) and polydimethylsiloxane/divinylbenzene (PDMS/DVB) TF samplers were fabricated using spin coating technique and glass wool fabric mesh as substrate. The samplers were easily tailored in size and shape by cutting tools. Good durability and flat-shape stability were observed during extractions and stirring in water. The latter characteristic obviates the need for an extra framed holder for rapid thin film microextraction (TFME) and makes the samplers more robust and user-friendly. The analytical performance of the MPTF devices was satisfactorily illustrated and compared with those of solid phase microextraction (SPME) fibers and PDMS thin film membrane using water samples spiked with seven N–nitrosamines (NAs), known as disinfection by-products (DBPs) in drinking water. Marked enhancement of extraction efficiencies (typically more than one order of magnitude) for the N-nitrosamines, including the hydrophilic ones, was obtained with the MPTF devices under generally pre-equilibrium conditions, compared to the SPME fibers and PDMS thin film membrane. The analytical results obtained in this study, including linearity, repeatability and detection levels at low ng/L for the tested compounds, indicate that the new thin film devices are promising for rapid sampling and sample preparation of trace levels of polar organic pollutants in water with sensitivities higher than SPME fibers and with a wide application range typical of mixed-phase coatings. The user-friendly format and robustness of the novel devices are also advantageous for on-site applications, which is the ultimate use of thin film samplers. Moreover, the thin film fabrication approach developed in this study offers the possibility of making other novel samplers with PDMS or different absorptive polymers such as polyacrylate (PA) and polyethylene glycol (PEG) as particle-free, or as particle-loaded thin films with a variety of adsorptive solid particles. In another development in the course of this research, the performance and accuracy of the SPME fiber approach for sample preparation of selected DBPs were demonstrated and compared with the conventional liquid-liquid extraction (LLE) method by real drinking water samples analysis in collaboration with Health Canada. Four regulated trihalomethanes (THMs) and seven other DBPs known as priority by-products, including four haloacetonitriles, two haloketones and chloropicrin, were analyzed in real samples during two separate comparative studies. In each study, duplicate samples from several water treatment and distribution systems in Canada, collected and stabilized under the same protocol, were analyzed in parallel by two independent labs; in the University of Waterloo by an optimized headspace SPME-GC-MS and in Health Canada by a LLE-GC-ECD (electron capture detection) method equivalent to EPA 551.1. The values for the concentration of the analytes in the samples obtained by the two methods were in good agreement with each other in majority of the cases indicating that SPME affords the promise of a dependable sample preparation technique for rapid DBPs analysis. In particular, it was shown that the SPME fiber approach combined with GC-MS is a fast reliable alternative to the LLE-GC-ECD (EPA 551.1) method for analysis of the regulated THMs in the concentration ranges that are typical and relevant for drinking water samples.
280

Effects of Coagulation on the Removal of Natural Organic Matter, Genotoxicity, and Precursors to Halogenated Furanones

Zheng, Dana 17 July 2013 (has links)
Disinfectants in drinking water can interact with natural organic matter (NOM) to form disinfection by-products (DBPs). Halogenated furanones (including MX and MCA) are a group of emerging DBPs that can account for a significant amount of the total mutagenicity found in drinking water. Source water characteristics and NOM removal capabilities of coagulation can greatly influence the formation of DBPs. This project examines the effects of bench scale coagulation and chlorination tests on NOM removal, DBP formation, and genotoxicity. NOM was characterized using liquid chromatography-organic carbon detection (LC-OCD). Experiments with Ottawa River, Otonabee River, and Lake Simcoe waters show that DBPs decreased with increases in coagulant dosage, due to the removal of NOM during coagulation. DBP formation and speciation was then compared with NOM content to identify specific fractions that contribute to the formation of these DBPs. Genotoxicity was directly linked to MX presence in chlorinated waters.

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