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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.
41

Ανάλυση συστατικών φύλλων Vaccinium corymbosum

Μερμίγκη, Πηνελόπη 19 August 2014 (has links)
Το Vaccinium corymbosum (Ericaceae) είναι ένας ψηλός θάμνος, ο οποίος καλλιεργείται σε περιοχές της Αμερικής και της Ευρώπης για τους υψηλής διατροφικής αξίας καρπούς του (κυανά μύρτιλλα: blueberries). Στη χώρα μας, καλλιέργεια μύρτιλλων γίνεται κυρίως στην περιοχή της Δράμας. Οι περισσότερες μελέτες εστιάζουν στην ανάλυση των συστατικών των καρπών, ενώ η φυτοχημική σύσταση των φύλλων δεν έχει μελετηθεί εκτενώς. Η παρούσα εργασία, στόχο είχε την ανάλυση των κυριότερων φαινολικών συστατικών των φύλλων του φυτού, με χρήση χρωματογραφικών μεθόδων ανάλυσης. Τα αποξηραμένα φύλλα, τα οποία χρησιμοποιήθηκαν στην παρούσα διατριβή, προέρχονται από τις ποικιλίες ‘Bluecrop’ και ‘Patriot’, βιολογικής καλλιέργειας στην περιοχή της Δράμας. Προετοιμάστηκε αφέψημα των αποξηραμένων φύλλων, το οποίο στη συνέχεια εκχυλίστηκε διαδοχικά, με οξικό αιθυλεστέρα (AcOEt) και βουτανόλη (BuOH). Κατόπιν και με σκοπό τον εύκολο προσδιορισμό των φαινολικών ενώσεων, πραγματοποιήθηκε όξινη υδρόλυση (90 oC, 2 h, 50% μεθανόλη) όλων των κλασμάτων: Crude (αφέψημα), AcOEt, BuOH και Aqueous. Η ανάλυση των συστατικών πραγματοποιήθηκε με Υγρή Χρωματογραφία Υψηλής Απόδοσης με Ανιχνευτή Συστοιχίας Φωτοδιόδων (HPLC-DAD) και ύστερα με Υγρή Χρωματογραφία Υπερυψηλής Απόδοσης (UPLC-MS) με Φασματόμετρο Μάζας, το οποίο διαθέτει υβριδικό αναλυτή τετραπόλου – χρόνου πτήσης (Q-TOF). Για την HPLC-DAD ανάλυση χρησιμοποιήθηκε στήλη αντίστροφης φάσης (Luna C-18), με σύστημα βαθμιδωτής έκλουσης με τρείς διαλύτες: διάλυμα οξικού αμμωνίου (CH3COONH4-10 mM), ακετονιτρίλιο και μεθανόλη (Μαργιάννη, 2011). Επιπλέον, για την ποσοτικοποίηση των κυριότερων φαινολικών συστατικών χρησιμοποιήθηκε σύστημα βαθμιδωτής έκλουσης με δύο διαλύτες: διάλυμα CH3COONH4-10 mM και ακετονιτρίλιο (τροποποίηση Tsao et al., 2003). Στην ανάλυση UPLC-ESI-MS χρησιμοποιήθηκε στήλη αντίστροφης φάσης (BEH C18), με σύστημα βαθμιδωτής έκλουσης με δύο διαλύτες: 0.1% μυρμηκικό οξύ σε H2O και ακετονιτρίλιο. Τα αποτελέσματα έδειξαν, αρχικά, ότι κανένα από τα κλάσματα δεν περιέχει ανθοκυανίνες, ενώ το AcOEt κλάσμα είναι περισσότερο εμπλουτισμένο σε φαινολικά συστατικά, σε σχέση με τα άλλα κλάσματα. Με χρήση της UPLC-ESI-MS ανάλυσης, προσδιορίσθηκαν διάφορα συστατικά μεταξύ των οποίων φαινολικά οξέα και φλαβονοειδή. Ενδιαφέρον παρουσίασε το γεγονός ότι το Aqueous κλάσμα περιείχε μόνο φαινολικά οξέα. Η επιλογή της μεθόδου της όξινης υδρόλυσης, φαίνεται να ήταν ικανοποιητική, αφού τα άγλυκα τμήματα των γλυκοζυλιωμένων φλαβονολών, αλλά και τα προϊόντα διάσπασης του εστερικού δεσμού του χλωρογενικού οξέος, προσδιορίσθηκαν εύκολα με την UPLC-ESI-MS ανάλυση. Στα επιμέρους δείγματα ποσοτικοποιήθηκαν, με χρήση HPLC-DAD ανάλυσης τα εξής φαινολικά συστατικά: χλωρογενικό οξύ, ρουτίνη, υπεροζίτης, ισοκερσιτρίνη και κερκετίνη. Συνεπώς, το αφέψημα των καλλιεργούμενων μύρτιλλων είναι μία καλή πηγή φαινολικών συστατικών. / Vaccinium corymbosum (Ericaceae) is a tall shrub, which is cultivated in parts of America and Europe for their fruits (blueberries), which possess high nutritional value. In our country, blueberries are mainly cultivated in the area of Drama. Many studies focus on the analysis of the constituents of fruits, while the phytochemical composition of leaves has not been studied in detail. The present study aimed the analysis of the main components of blueberry leaves, using chromatographic techniques. Dried leaves (var ‘Bluecrop’ and ‘Patriot’) were obtained from the Cooperative ‘‘Biodrama’’. The decoction of dried leaves was prepared and then extracted sequentially with ethyl acetate and butanol. In order to easily identify the phenolic compounds, all fractions (Crude or decoction, AcOEt, BuOH and Aqueous) were hydrolysed in acid conditions (90 oC, 2 h, 50% MeOH). The components of the fractions were analyzed firstly by High Performance Liquid Chromatography with Diode Array Detector (HPLC-DAD) and then with Ultra High Performance Liquid Chromatography (UPLC-MS) with Mass Spectrometry. The mass spectrometer features hybrid quadrupole - time of flight (Q-TOF) analyzer. For the HPLC-DAD analysis a reverse phase column (Luna C-18) was used with a gradient elution system with three solvents: ammonium acetate (CH3COONH4-10 mM), acetonitrile (AcCN) and methanol (MeOH) (Margianni, 2011). Moreover, the quantification of the major phenolic components system was done with a gradient elution system of CH3COONH4-10 mM and AcCN (modified from Tsao et al., 2003). UPLC-ESI-MS was performed on a reverse phase column (BEH C18) with a gradient elution system with two solvents: 0.1% formic acid in H2O and AcCN. Firstly, the results showed that none of the fractions contain anthocyanins while AcOEt fraction is more enriched in phenolic compounds, in comparison to the other fractions. Using UPLC-ESI-MS analysis, we identified several components including phenolic acids and various flavonoids. Interestingly, the Aqueous fraction contained only phenolic acids. The choice of the method of acid hydrolysis appears to be satisfactory for identification purposes, since the aglycones of glycosylated flavonols, and the cleavage products of the chlorogenic acid, was determined easily by UPLC-ESI-MS analysis. The phenolic compounds: chlorogenic acid, rutin, hyperoside, isoquercitrin and quercetin were quantified in blueberry leaf decoction using HPLC-DAD. Therefore, the decoction of cultivated blueberries is a good source of phenolic compounds.
42

Development and evaluation of sample preparation procedure for human plasma samples in LC/MS-based metabolomics

Kölfeldt, Niklas January 2015 (has links)
The aim of this master thesis project was to develop methods for sample preparation and analysis by LC-MS suitable for global metabolomics of human plasma samples. In this thesis six different methods was tested, based on precipitation, solid phase extraction (SPE), and ultrafiltration. The methods differ in their mechanisms of action, but the end goal is the same, to remove the proteins and other high molecular weight compounds from the samples and to retain as many metabolites as possible in a reproducible manner. The LC-MS analysis were performed on a C18 and a HILIC type column using electrospray ionization (ESI) with both positive and negative ionization to cover as much of the metabolome as possible. The MarkerLynx software was then used to extract features from the chromatograms. The coefficient of variation (CV) was calculated and the features with CV > 30 % were removed. The features were then used to compare the methods with each other in order to see whether any of the methods yielded the same capture of features. The largest amount of features was detected for precipitation with MeOH when using a C18 type column. For HILIC type columns precipitation with MeOH with a small addition of H3PO4 resulted in most unique features detected. The ionization mode was found to be less important, compared whit the choice of column, but more features was detected using positive mode than negative mode.
43

Desenvolvimento e validação de métodos analíticos e estudos de estabilidade da rivaroxabana

Wingert, Nathalie Ribeiro January 2015 (has links)
A análise de fármacos é fundamental nas diversas fases do desenvolvimento farmacêutico, tais como estudos de formulação, estabilidade e controle de qualidade do produto. A rivaroxabana (RIV) é um anticoagulante de uso oral indicado para prevenção da formação de coágulos venosos. A literatura pesquisada apresenta poucos relatos de determinação quantitativa e de estudos de estabilidade do fármaco em comprimidos. E ainda nenhum método analítico em compêndios oficiais Diante do exposto, o objetivo deste trabalho foi desenvolver e validar métodos analíticos para determinação qualitativa e quantitativa da RIV por cromatografia líquida de alta eficiência com detecção por UV e de ultra eficiência com detecção por espectrometria de massas (CLAE-UV e CLUE-EM) e eletroforese capilar (EC). Os resultados encontrados foram adequados conforme o preconizado nos guias oficiais nacionais e internacionais. Foi avaliada também a viabilidade da técnica de eletroforese capilar em microchip para análise de RIV. Através de método desenvolvido por CLAE foi realizado estudo de cinética de degradação e posterior avaliação do potencial tóxico in vitro das amostras de degradação forçada da RIV. A identificação de três produtos de degradação majoritários da RIV, formados a partir de estresse ácido, alcalino e fotolítico, foi realizada por CLUE-EM/EM, possibilitando a proposição da estrutura molecular de cada produto de degradação. O potencial tóxico da RIV antes e depois da exposição à degradação forçada foi avaliado através dos métodos in vitro MTT, Vermelho Neutro, Ensaio Cometa e DNA de baixo peso molecular. Não foram encontrados sinais de dano ao DNA celular, contudo, amostras de RIV expostas ao meio alcalino apresentaram maior redução da viabilidade celular. O trabalho avaliou ainda o perfil de dissolução da RIV em comprimidos baseado nos dados de absorção in vitro conforme modelagem in silico dos dados, estabelecendo uma correlação linear entre a fração absorvida e fração dissolvida. As diferentes metodologias e técnicas desenvolvidas e aplicadas nesse trabalho contribuem para o desenvolvimento do controle de qualidade farmacêutico na direção de ensaios mais confiáveis que garantam a segurança e eficácia de medicamentos. / Drug analysis is critical at various stages of pharmaceutical development, such as formulation studies, stability and quality control products. Rivaroxaban (RIV) is an oral anticoagulant indicated for prevention of thromboembolism. Literature contains few reports of quantitative determination and drug stability studies of RIV on pharmaceutical formulation. Analytical method for RIV quality control are not evaluable on official guides yet. This research work aimed to develop and validate analytical methods for qualitative and quantitative determination of RIV by high and ultra performance liquid chromatography with UV detection mass spectrometry detection (HPLC -UV and UPLC-MS) and capillary electrophoresis (CE). The results were adequate as recommended in national and international official guides. Reliability of RIV analysis by microchip capillary electrophoresis was also assessed. Through the method developed by HPLC degradation kinetic studies were performed, zero order kinetic has better description of RIV degradation behaviour. RIV toxic potential before and after exposure to forced degradation was assessed by in vitro methods of MTT, Neutral Red, Comet Assay, and Low Molecular Weight DNA. There were no signals of DNA damage however, RIV samples exposed to alkaline medium showed increased reduction in cell viability. Identification of RIV degradation products formed after exposure to acid and alkaline media and UVC radiation was performed by UPLC-MS / MS. It was possible to elucidate molecular structures of three major degradation products. This study also assessed the dissolution profile of RIV tablets based on in vitro absorption data, a linear point-to-point correlation was found for fraction absorbed and dissolved. Different methodologies and techniques developed and applied in this work can contribute to the development of pharmaceutical quality towards more reliable tests to ensure safety and efficacy of medicines.
44

Sledování obsahu biogeních aminů a polyaminů během skladování a tepelných úprav skopového masa. / Changes of biogenic amines and polyamines content during storage and heat treatments of mutton.

LÍSKOVCOVÁ, Lucie January 2012 (has links)
The aim of this thesis was to determine the content of biogenic amines and polyamines, specifically putrescine (PUT), spermidine (SPD) and spermine (SPM) in mutton meat during storage and heat treatment. The meat of slaughter animals is rich in these amines but, unfortunately, data on the content of mutton meat whether in slaughter bodies as well as during storage or heat treatments in the literature are still missing. The samples were provided by small farmers and the animals were hybrids of several breeds. The samples were taken from the thigh and back. The samples of lamb meat were frozen and the ones were watched from 0-6 months. The samples of leg were cooled and packed into three different types of packaging. It was the type of packaging in a polyethylene bag (PE), vacuum packed (VP) and controlled atmosphere packaging (MAP). All the samples were analyzed in the days and also on the initial concentration at day 0. For frozen and cooled (chilled) samples which were stored in PE and VP was observed the decrease in all monitored amines. Only the packaging in MAP occurred in the SPD to a slight increase over the initial content. From heat treatments were performed usual preparations of the meals which are made in central Europe and the meals were cooked on particular days. The highest decrease was measured in roasted meat, then stewed and cooked meat in this order. Reported data are comparable to published data for pork and beef meat stored under the same or similar conditions. I think that these data can help to extend the data in the literature.
45

Desenvolvimento e validação de métodos analíticos e estudos de estabilidade da rivaroxabana

Wingert, Nathalie Ribeiro January 2015 (has links)
A análise de fármacos é fundamental nas diversas fases do desenvolvimento farmacêutico, tais como estudos de formulação, estabilidade e controle de qualidade do produto. A rivaroxabana (RIV) é um anticoagulante de uso oral indicado para prevenção da formação de coágulos venosos. A literatura pesquisada apresenta poucos relatos de determinação quantitativa e de estudos de estabilidade do fármaco em comprimidos. E ainda nenhum método analítico em compêndios oficiais Diante do exposto, o objetivo deste trabalho foi desenvolver e validar métodos analíticos para determinação qualitativa e quantitativa da RIV por cromatografia líquida de alta eficiência com detecção por UV e de ultra eficiência com detecção por espectrometria de massas (CLAE-UV e CLUE-EM) e eletroforese capilar (EC). Os resultados encontrados foram adequados conforme o preconizado nos guias oficiais nacionais e internacionais. Foi avaliada também a viabilidade da técnica de eletroforese capilar em microchip para análise de RIV. Através de método desenvolvido por CLAE foi realizado estudo de cinética de degradação e posterior avaliação do potencial tóxico in vitro das amostras de degradação forçada da RIV. A identificação de três produtos de degradação majoritários da RIV, formados a partir de estresse ácido, alcalino e fotolítico, foi realizada por CLUE-EM/EM, possibilitando a proposição da estrutura molecular de cada produto de degradação. O potencial tóxico da RIV antes e depois da exposição à degradação forçada foi avaliado através dos métodos in vitro MTT, Vermelho Neutro, Ensaio Cometa e DNA de baixo peso molecular. Não foram encontrados sinais de dano ao DNA celular, contudo, amostras de RIV expostas ao meio alcalino apresentaram maior redução da viabilidade celular. O trabalho avaliou ainda o perfil de dissolução da RIV em comprimidos baseado nos dados de absorção in vitro conforme modelagem in silico dos dados, estabelecendo uma correlação linear entre a fração absorvida e fração dissolvida. As diferentes metodologias e técnicas desenvolvidas e aplicadas nesse trabalho contribuem para o desenvolvimento do controle de qualidade farmacêutico na direção de ensaios mais confiáveis que garantam a segurança e eficácia de medicamentos. / Drug analysis is critical at various stages of pharmaceutical development, such as formulation studies, stability and quality control products. Rivaroxaban (RIV) is an oral anticoagulant indicated for prevention of thromboembolism. Literature contains few reports of quantitative determination and drug stability studies of RIV on pharmaceutical formulation. Analytical method for RIV quality control are not evaluable on official guides yet. This research work aimed to develop and validate analytical methods for qualitative and quantitative determination of RIV by high and ultra performance liquid chromatography with UV detection mass spectrometry detection (HPLC -UV and UPLC-MS) and capillary electrophoresis (CE). The results were adequate as recommended in national and international official guides. Reliability of RIV analysis by microchip capillary electrophoresis was also assessed. Through the method developed by HPLC degradation kinetic studies were performed, zero order kinetic has better description of RIV degradation behaviour. RIV toxic potential before and after exposure to forced degradation was assessed by in vitro methods of MTT, Neutral Red, Comet Assay, and Low Molecular Weight DNA. There were no signals of DNA damage however, RIV samples exposed to alkaline medium showed increased reduction in cell viability. Identification of RIV degradation products formed after exposure to acid and alkaline media and UVC radiation was performed by UPLC-MS / MS. It was possible to elucidate molecular structures of three major degradation products. This study also assessed the dissolution profile of RIV tablets based on in vitro absorption data, a linear point-to-point correlation was found for fraction absorbed and dissolved. Different methodologies and techniques developed and applied in this work can contribute to the development of pharmaceutical quality towards more reliable tests to ensure safety and efficacy of medicines.
46

Perfil de compostos fenólicos extraídos de folhas de ora-pro-nóbis (Pereskia Aculeata Miller) / Phenolic compouds extracted from leaves of ora-pro-nóbis (Pereskia Aculeata Miller)

Souza, Thaís Cristina Lima de, 1989- 25 August 2018 (has links)
Orientador: Helena Teixeira Godoy / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-25T00:05:44Z (GMT). No. of bitstreams: 1 Souza_ThaisCristinaLimade_M.pdf: 979807 bytes, checksum: dc7c129a05318e6db72f5cdfcf42e98a (MD5) Previous issue date: 2014 / Resumo: O ora-pro-nóbis (OPN) (Pereskia aculeata Miller) é uma trepadeira arbustiva, pertencente à família Cactaceae. Suas folhas são muito utilizadas na culinária mineira, mas pouco usada e quase desconhecida pela população no resto do país. Dados referentes ao perfil de compostos fenólicos dessa planta são inexistem na literatura. Por esse motivo, o presente trabalho teve como objetivo otimizar um método de extração para os compostos fenólicos presentes nas folhas de OPN. Bem como, desenvolver e validar um método de cromatografia de ultra eficiência (CLUE), para separação e identificação do perfil desses fenólicos. A partir dos resultados obtidos para o planejamento fatorial empregado, as condições escolhidas de extração foram: água como solução extratora, com 1 Mol.L-1 de HCl, temperatura igual a 80 ºC e tempo de 90 minutos. O método cromatográfico desenvolvido apresentou resultados satisfatórios, em relação aos critérios de validação, mostrando-se adequado para a separação e quantificação dos cinco compostos fenólicos estudados. Para as amostras de OPN analisadas, os teores de compostos fenólicos encontrados, variaram entre 4051,05 e 5892,19 mg.Kg-1 para o ácido clorogênico, 353,48 e 1139,91 mg.Kg-1 para o ácido caféico, 327,52 e 469,35 mg.Kg-1 para o ácido p-coumárico entre 347,47 e 458,84 mg.Kg-1 para o ácido ferúlico. A presença desses derivados de ácidos hidroxicinâmicos nas amostras indica que as mesmas possuem uma alta atividade antioxidante, embora seja necessária a realização de análises adequadas para tal afirmação. Além disso, as concentrações encontradas para esse ácidos fazem do OPN uma importante fonte de fenólicos, e seu consumo pode contribuir para uma dieta mais saudável / Abstract: The ora-pro-nobis (OPN) (Pereskia aculeata Miller) is a climbing shrub belonging to the Cactaceae family. The leaves of this vegetable are widely used in the popular cuisine of the estate of Minas Gerais, Brasil, but little its almost unknown by the population in the rest of the country. There is no studies were found regarding the profile of phenolic compounds presented by the leaves of OPN, as far as we concerned. Therefore, this study aimed to optimize a method for extracting of phenolic compounds present in the leaves of OPN. As well as develop and validate a method of ultra performance liquid chromatography (UPLC) for separation and identification of these phenolic compounds. The results obtained for the factorial design employed, allowed to chose the extraction conditions: water as extraction solution, with 1 mol.L-1 HCl, temperature of 80 º C and a time of 90 minutes. The results acquired for the method validation showed good results for repeatability and intermediate precision, indicating that the method is suitable for the separation and quantification of the five phenolic compounds studied. For the OPN samples analyzed, the content of phenolic compounds found ranged from 4051.05 and 5892.19 mg.Kg-1 for chlorogenic acid; 353.48 and 1139.91 mg.Kg-1 for caffeic acid; 327.52 and 469.35 mg.Kg-1 for p-coumaric acid; 347.47 and 458.84 mg.Kg-1 for ferulic acid. The presence of these derivatives of hydroxycinnamic acids indicates that they possess a high antioxidant activity, while appropriate analyzes must be conducting for such a claim. Furthermore, the concentrations found for these acids make OPN an important source of phenolic and its consumption can contribute to a healthier diet / Mestrado / Ciência de Alimentos / Mestra em Ciência de Alimentos
47

Micotoxinas em matrizes de milho e trigo: validação de método analítico por ULPC-MS/MS e monitoramento em diferentes pontos da cadeia produtiva e comercial / Mycotoxins in matrices of maize and wheat: validation an analytical method by UPLC-MS/MS and monitoring at different points of supply and commercial chain

Souza, Darliana Mello 24 February 2014 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This study aims to validate an analytical multi-mycotoxin method using UPLC-MS/MS for 12 mycotoxins determination in wheat and maize matrices. The parameters evaluated for the validation were: calibration curve and linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy (recovery%), precision (RSD %) and matrix effect. The extraction of mycotoxins was performed using the modified QuEChERS method, whereby were used 12.5 g of slurry (suspension between sample and water), 4.5 g MgSO4 anhydrous and 10 ml of acidified acetonitrile at 1% acetic acid. After method validation, it was used to search, quantitatively, the occurrence of mycotoxins in 646 samples, 476 samples of wheat (the field trials, exported and imported grain type, grain processing and their fractions (flour and bran) and flour collected in supermarkets) and 170 samples of maize (grain exported type, flour collected in supermarkets, grains and brewer for the manufacture of animal feed). The results were satisfactory for all evaluated parameters, thus showing that the method validated for the matrices of wheat and maize, it is effective to determine these 12 mycotoxins studied. The matrix effect for some mycotoxins was outside the range -20 to +20%. These results for some analytes were compensated by matrix-mached calibration. All were contaminated by at least one of 12 mycotoxins in the study, regardless of origin. The mycotoxin DON was predominantly found in wheat samples, while fumonisin were determined in maize. In the field trials, factors such as genotype, environment and fungicide treatment had influence on DON concentration. Wheat grain for exportation and imported from Argentina had DON contamination in all samples. In wheat for exportation, also been determined contamination for FB1, FB2, ZEN and OTA. There is evidence that this is the first study to report the presence of fumonisins in Brazilian wheat, since it was not found other reports in the literature. In the sub-products of milling was observed redistribution of DON, a decreased concentration in white flour and increased in bran fraction when compared to the initial concentration in the grain, showing that this process is not effective for mycotoxins removal. It was determined DON and ZEN mycotoxins in flour samples purchased either in the city of Cruz Alta as Santa Maria as well. In maize samples for exportation was observed concomitant contamination by DON, ZEN, FB1 and FB2 and AFLA B1. In maize flour samples collected from supermarkets all samples were contaminated with fumonisins. Besides fumonisins evidenced the presence of DON, ZEN and AFLA B1 in some samples. Samples destined for the production of animal feed were determineted with aflatoxins (B1, B2, G1, G2), fumonisins (B1 and B2), DON and ZEN, and in some samples, the concentrations were higher than Brazilian MRL. The extraction method combined with modern chromatographic technique for the determination of analytes, were effective for the analysis of mycotoxins in wheat and maize. Even in concentrations below the legal limits, human been exposure to mycotoxins can occur constantly. Monitoring of mycotoxins in foods is extremely important for public health, seeking quality to make healthy products available at all points of the supply and commercial chain. / O trabalho teve por finalidade validar um método analítico multimicotoxinas empregando UPLC-MS/MS para determinação simultânea de 12 micotoxinas em matrizes de trigo e milho. Os parâmetros avaliados para validação do método foram: curva analítica e linearidade, limite de detecção (LOD), limite de quantificação (LOQ), exatidão (recuperação%), precisão (RSD%) e efeito matriz. A extração das micotoxinas foi realizada empregando o método QuEChERS modificado, no qual foram utilizados 12,5 g de slurry (suspensão entre amostra e água), 4,5 g MgSO4 anidro e 10 mL de acetonitrila acidificada a 1% com ácido acético. Após a validação do método, o mesmo foi empregado para pesquisar, quantitativamente, a ocorrência de micotoxinas em 646 amostras, sendo 476 amostras de trigo (ensaios a campo, grãos tipo exportação e importação, grãos para processamento e respectivas frações (farinha e farelo) e farinhas comercializados em supermercados) e 170 amostras de milho (grãos tipo exportação, farinhas coletadas em supermercados, grãos e quirera destinados à fabricação de ração animal). Os resultados obtidos foram satisfatórios para todos os parâmetros avaliados, mostrando desta forma, que o método validado para as matrizes de trigo e milho, é eficaz para determinar as 12 micotoxinas em estudo. O efeito matriz, para algumas micotoxinas ficou fora da faixa de -20 a +20%. Esse efeito pronunciado para alguns analitos foi compensado pela calibração por superposição da matriz. Este método pode então ser utilizado para avaliação das amostras, em que todas apresentaram contaminação por pelo menos uma das 12 micotoxinas estudadas, independente da origem. A micotoxina DON foi predominantemente encontrada em amostras de trigo, enquanto fumonisinas foram as micotoxinas predominante determinadas em milho. Nos ensaios a campo, fatores como genótipo, ambiente e tratamento fungicidas tiveram influência sobre as concentrações de DON. Grãos de trigo tipo exportação e importados da Argentina apresentaram contaminação por DON em todas as amostras. Em trigo tipo exportação, também foi determinado contaminação por FB1, FB2, ZEN e OTA. Há evidências de que este seja o primeiro trabalho a relatar a presença de fumonisinas em trigo brasileiro, visto que não foi encontrado outros relatos na literatura. Nos subprodutos derivados da moagem foi verificado redistribuição de DON, com redução das concentrações na farinha branca e incremento na fração farelo, quando comparados a concentração inicial no grão, evidenciando que tal processo não é eficaz para eliminação de micotoxinas. Foram determinadas as micotoxinas DON e ZEN em amostras de farinhas adquiridas tanto na cidade de Cruz Alta quanto de Santa Maria. Nas amostras de milho tipo exportação foi evidenciada contaminação concomitante por DON, ZEN, FB1 e FB2 e AFLA B1. Nas amostras de farinha de milho coletadas em supermercados todas estavam contaminadas por fumonisinas. Além de fumonisinas foi evidenciado a presença de DON, ZEN e AFLA B1 em algumas amostras. Em amostras destinadas a fabricação de ração animal foi determinada aflatoxinas (B1, B2, G1, G2), fumonisinas (B1 e B2), DON e ZEN, sendo que em alguns casos, as concentrações foram superiores aos limites tolerados pela legislação brasileira. O método de extração, aliado com a técnica cromatográfica para determinação dos analitos mostraram-se eficientes para a análise de micotoxinas em trigo e milho. Mesmo em concentrações abaixo dos limites legais, a exposição humana a micotoxinas pode ocorrer constantemente. O monitoramento de micotoxinas em alimentos é de extrema importância para a saúde pública, visando a disponibilização de produtos de qualidade em todos os pontos da cadeia produtiva e comercial.
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SOURCE, DISTRIBUTION AND FATE OF THE KEY NATURAL FREE AND CONJUGATED ESTROGENS IN THE AQUATIC ENVIRONMENT WITH RISK ASSESSMENT AND MITIGATION STRATEGIES / 水環境に見出される抱合体を含むエストロゲンの起源、分布、挙動に基づくリスク評価と対策

KUMAR, Vimal 23 March 2010 (has links)
Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第15364号 / 工博第3243号 / 新制||工||1488(附属図書館) / 27842 / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 田中 宏明, 教授 藤井 滋穂, 教授 米田 稔 / 学位規則第4条第1項該当
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Long-range Transport of Per- and Polyfluorinated Substances to Sweden : The Exposure in Mountain Grazing Reindeers

Johansson, Malin January 2016 (has links)
The aim of this study was to examine if perfluorinated alkylated substances (PFASs) reaches north of Sweden by long-range atmospheric transport. This was done by monitoring the levels of PFASs in reindeer livers at two locations in 2002 and 2010, respectively. The reindeers have lived all of their lives in the mountains and therefore the main source of exposure for PFASs is through air. The samples were extracted and analysed for 24 different PFASs using ultra performance liquid chromatography tandem mass spectrometer (UPLC-MS/MS). The most significant change concerns perfluorooctane sulfonic acid (PFOS) which decreased significantly from 6.1 ng/g at the most northern location (Ammarnäs/Biergenis) in 2002 to 0.87 ng/g 2010. At the other sampling location, Glen, PFOS decreased from 5.0 to 3.2 ng/g during the eight years. Mainly PFOS and longer chain carboxylates were found. The results revealed that the levels of many compounds decreased in time. The location seems to have an impact on the level of perfluorinated compounds present and most likely the distribution of them in the air, since certain PFASs have increased and decreased differently in time between the two locations. Since PFASs are non-volatile, they are believed to be degradation products of volatile compounds such as fluorotelomer alcohols (FTOHs) and perfluoroalkylated sulfonamido alcohols (FOSEs). FTOHs and FOSEs are released, translocated by long-range atmospheric transport and degraded to perfluorinated compounds in organisms or atmosphere.
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Stabilita vybraných mykotoxinů v pivu / Stability of selected mycotoxins in beer

Štáblová, Taťána January 2020 (has links)
Mycotoxins are secondary metabolites of moulds, which attack cereals, for example barley, from which mycotoxins then get to beer. This submitted work is focused on ochratoxin A, deoxynivalenol and zearalenone, which can occur in beer. The first part of this master’s thesis consists of literary research, which describes mycotoxins in general, points out their occurrence, prevention of their formation and delivers information about their physical and chemical properties and toxicity. Furthermore, the research contains basis of malt and beer technology, the occurrence of mycotoxins in beer and raw materials for its production. The research describes changes in concentration of mycotoxins across malt and beer production. The next part deals with possibilities of determination of mycotoxins in barley, malt and beer, compares individual methods of their determination and points out many difficulties of some analyses. The experimental part of this work pursues determination of ochratoxin A, deoxynivalenol and zearalenone in different types of beer with the help of UPLC-FLR, HPLC-MS and ELISA. Instrumental techniques are validated and gathered results are compared with the results in literature. The goal of this master’s thesis is to assess the stability of ochratoxin A and deoxynivalenol in beer over time. The gained results show that there are changes in the concentration of ochratoxin A over time, nevertheless those changes show no pattern. Overall, there was a decrease in concentration in 47 % of the samples and an increase in 28 % of them. In the rest of the samples the concentration did not change. The concentration of deoxynivalenol does not change over time. One of the other goals of this thesis is monitoring of selected mycotoxins in beer. The average concentration of ochratoxin A in the samples was 39 ng/l and deoxynivalenol 9,9 g/l. Zearalenone did not occur in any of the samples when determined by liquid chromatography. All results agree with literature. Next, the thesis compares different analytical methods for determination of ochratoxin A, deoxynivalenol and zearalenone. The screening method ELISA is compared to UPLC-FLR and HPLC-MS. The determination of ochratoxin A by ELISA has shown to be time consuming, nevertheless the results responded to instrumental technique. ELISA overestimated the results of determination of deoxynivalenol in beer by 363–697 % and with zearalenone there were found false positive results.

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