In this thesis, it is shown how aflatoxins can be determined in biological material. The thesis is a summary of five papers. Aflatoxins are carcinogenic mycotoxins produced by Aspergillus moulds. Methods were developed for the determination of aflatoxins in samples of airborne dust and human urine collected at feed factories. For the dust samples from such agricultural products as copra, cotton seed and maize, methods were developed for the determination of aflatoxins B1, B2, G1 and G2. For urine samples, methods were developed for analysing the four aflatoxins above that naturally occur in dust, and the metabolites aflatoxins M1 and Q1. Sample preparation of dust samples included solvent extraction, filtration and immunoaffinity column extraction. Urine samples were cleaned up using immunoaffinity column extraction or solid-phase extraction using ethyl bonded-phase columns. All extractions with these columns were automated by means of a laboratory robot. Reversed-phase liquid chromatography was used to separate the aflatoxins in the cleaned-up extracts. Detection was performed by fluorescence after post-column derivatization by addition of bromine. Parameters for the derivatization were studied using factorial designs. To confirm the identity of aflatoxins in naturally contaminated airborne dust samples and spiked urine, liquid chromatography was combined with electrospray mass spectrometry. The detection limits of the aflatoxins in dust samples were in the range 1.8-3.1 ng/g in 10-mg dust samples using fluorescence detection. Aflatoxins were determined in spiked urine down to the 6.8-18 pg/ml level. In naturally contaminated dust of copra and cotton seed, aflatoxins were detected with a content of 9-50 pg/mg of aflatoxin Bi. No aflatoxins could be detected in any urine sample obtained from feed factory workers that were less than 6.8 pg/ml of aflatoxins B1, B2, G1 and G2 and less than 18 pg/ml of aflatoxins M1 and Q1. / <p>Diss. (sammanfattning) Umeå : Univ., härtill 5 uppsatser</p> / digitalisering@umu

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-04-18T19:29:49Z No. of bitstreams: 1 2012 - Felipe Machado Trombete.pdf: 1177577 bytes, checksum: 5ad9ebc406a8cd78d15ebfdc7acb27ff (MD5) / Made available in DSpace on 2017-04-18T19:29:49Z (GMT). No. of bitstreams: 1 2012 - Felipe Machado Trombete.pdf: 1177577 bytes, checksum: 5ad9ebc406a8cd78d15ebfdc7acb27ff (MD5) Previous issue date: 2012-02-29 / CAPES / The grated parmesan cheese is a food commonly consumed in Brazil and, in the last decade, few studies evaluated their quality. The aim of this research was to evaluate the adequacy and the levels of aflatoxin M1 in the grated parmesan cheese marketed in the Metropolitan Region of Rio de Janeiro in relation to the recommendations of current legislation. For this, were analyzed 30 samples representing 10 major brands sold in the region. In the evaluation of quality, were analyzed the levels of moisture, water activity, pH, acidity, sorbic acid and indicator microorganisms of hygienic quality and sanitary. The research of AFM1 was carried out by high performance liquid chromatography with fluorescence detection (HPLC-DFL) preceded by purification by immunoaffinity chromatography. Only 14 of the 30 samples analyzed (46.7%) were in accordance with the legislation that regulates the product quality. Beyond the lack of uniformity in production, the major irregularities were due to excessive moisture content and also by the abusive addition of the preservative sorbic acid. These results suggest the occurrence of faults on Good Manufacturing Practices by the industries responsible for the brands tested, which represents beyond economic fraud, risks to consumers health, even if indirectly. With relation to research of AFM1, all samples showed satisfactory values with the national legislation. However, the existing limit for aflatoxin in this product is excessively high when compared with those established by others countries. If compared with the regulation prevailing in the European Union, 8 samples (26.7%) could be considered contaminated. / O queijo parmes?o ralado ? um alimento popularmente consumido no Brasil e, na ?ltima d?cada poucos trabalhos objetivaram estudar sua qualidade. Esta pesquisa objetivou avaliar a adequa??o do queijo parmes?o ralado comercializado na Regi?o Metropolitana do Rio de Janeiro em rela??o ao preconizado pela legisla??o atual e tamb?m pesquisar os ?ndices de aflatoxina M1 (AFM1) no produto. Para tal, foram analisadas 30 amostras representativas das 10 principais marcas comercializadas na regi?o. Na pesquisa da qualidade, foram analisados os teores de umidade, atividade de ?gua, pH, acidez titul?vel, conservante ?cido s?rbico e microrganismos indicadores da qualidade higi?nica e sanit?ria. J? a pesquisa de AFM1 foi realizada por cromatografia l?quida de alta efici?ncia com detec??o por fluoresc?ncia (CLAE-DF), precedida de purifica??o por Cromatografia de Imunoafinidade. Apenas 14 amostras das 30 analisadas (46,7%) estavam em acordo com a legisla??o que regulamenta a qualidade do produto. Al?m da falta de uniformidade na produ??o, as principais irregularidades constatadas foram referentes ao excessivo teor de umidade e tamb?m pela adi??o abusiva do conservante ?cido s?rbico. Tais resultados sugerem a ocorr?ncia de falhas nas Boas Pr?ticas de Fabrica??o pelas ind?strias respons?veis pelas marcas analisadas, o que representa al?m de fraude econ?mica, riscos ? sa?de do consumidor, mesmo que de forma indireta. Com rela??o a pesquisa de AFM1, todas as amostras se adequaram a legisla??o nacional. No entanto, o limite existente para a presen?a da toxina neste produto ? excessivamente alto quando comparado com os estabelecidos por outros pa?ses. Se comparado com a regulamenta??o predominante na Uni?o Europ?ia, 8 amostras (26,7%) poderiam ser consideradas contaminadas.

Fumonisins, carcinogenic mycotoxins produced by various Fusarium species, occur naturally in maize and maize-based food products. They are hazards for animal and human health as they cause cancer in rodents and have been associated with oesophageal cancer and neural tube defects in humans. The most abundant naturally occurring fumonisins analogues in maize are fumonisin B1, B2 and B3 (FB1, FB2 and FB3). For analytical determination, they mostly require suitable extraction, clean-up and pre or post-column derivatization together with reversed-phase HPLC separation. o- Phthaldialdehyde (OPA) had been adopted as the most widely used derivatization reagent for fumonisins as they lack useful chromophores or fluorophores. Alternative derivatization reagents, naphthalene-2,3- dicarboxaldehyde (NDA) and dansyl chloride (DnS-Cl), were investigated in this study

Fumonisins, carcinogenic mycotoxins produced by various Fusarium species, occur naturally in maize and maize-based food products. They are hazards for animal and human health as they cause cancer in rodents and have been associated with oesophageal cancer and neural tube defects in humans. The most abundant naturally occurring fumonisins analogues in maize are fumonisin B1, B2 and B3 (FB1, FB2 and FB3). For analytical determination, they mostly require suitable extraction, clean-up and pre or post-column derivatization together with reversed-phase HPLC separation. o- Phthaldialdehyde (OPA) had been adopted as the most widely used derivatization reagent for fumonisins as they lack useful chromophores or fluorophores. Alternative derivatization reagents, naphthalene-2,3- dicarboxaldehyde (NDA) and dansyl chloride (DnS-Cl), were investigated in this study

Masters of Science / Fumonisins, carcinogenic mycotoxins produced by various Fusarium species, occur naturally in maize and maize-based food products. They are hazards for animal and human health as they cause cancer in rodents and have been associated with oesophageal cancer and neural tube defects in humans. The most abundant naturally occurring fumonisins analogues in maize are fumonisin B1, B2 and B3 (FB1, FB2 and FB3). For analytical determination, they mostly require suitable extraction, clean-up and pre or post-column derivatization together with reversed-phase HPLC separation. o- Phthaldialdehyde (OPA) had been adopted as the most widely used derivatization reagent for fumonisins as they lack useful chromophores or fluorophores. Alternative derivatization reagents, naphthalene-2,3- dicarboxaldehyde (NDA) and dansyl chloride (DnS-Cl), were investigated in this study. / South Africa

Preterm birth (PTB) results in over 15 million early births annually and is the leading cause of neonatal deaths. There are no clinical methods currently available to evaluate risk of PTB at early stages in pregnancy; thus, a rapid diagnostic to analyze PTB risk would be beneficial. Microfluidic immunoaffinity extraction is a promising platform for preparing complex samples, such as maternal serum with PTB risk biomarkers. 3D printed microfluidic devices have advantages over conventional microfluidic systems including simple fabrication and potential for iterative optimization to improve designs. In this work, I developed immunoaffinity monoliths in 3D printed microfluidic devices modified with antibodies to enrich PTB biomarkers from human blood serum. I retained and eluted a peptide PTB biomarker in both buffer and blood serum using an immunoaffinity column. An additional three PTB biomarkers were also successfully extracted either from buffer or blood serum on single-antibody columns. Both polyclonal and monoclonal antibodies to PTB biomarkers were characterized by dot blots, biolayer interferometry, and surface plasmon resonance to determine their specificity and dissociation constants. I created multiplexed immunoaffinity columns to simultaneously enrich three PTB biomarkers from depleted human blood serum in a single extraction. This is the first demonstration of multiplexed immunoaffinity columns for PTB biomarkers in a 3D printed microfluidic device. My work is a key step towards the future development of 3D printed microfluidic devices for rapid PTB testing.