This master thesis deals with monitoring of a content of deoxynivalenol, its metabolite deoxynivalenol-3-b-D-glucopyranoside and ochratoxin A in beer samples collected from retail market in the Czech Republic, Poland and Slovakia. The theoretical part describes general characteristics of mycotoxins, its transfer from field barely through malt to beer and its occurrence in beers. Malting process and brewing technology were also mentioned. Subsequently possibilities for a determination of the mycotoxins by the chromatografic and immunochemical method were presented. The experimental section describes analysis of 30 samples of beer. The analyses were conducted using ultra high-performance liquid chromatography with fluorimetric detection (UPLC/FLR) for ochratoxin A and high-performance liquid chromatography coupled with mass spectrometer (HPLC/MS) for deoxynivalenol and its metabolite. Ochratoxin A was detected in 25 of the 30 samples in concentration range of 0,6 - 82,5 ng·l-1. Deoxynivalenol was found in 24 of the 30 samples with concentration range of 2,29 - 12,57 ug·l-1 and deoxynivalenol-3-b-D-glucopyranoside was occure in 19 of the 30 samples in concentration range of 2,45 - 12,47 ug·l-1. It was also assessed the relationship between beer gushing and presence of mycotoxins in beer. No connection between the parameters has been found. Consequently it is not possible to predict beer gushing from the presence of mycotoxins.

The topic of this Master thesis is The Monitoring of Biologically Active Substances of Coffee. The technological production of coffee beans from harvesting the crops to the final packaging is described in the theoretical part, together with the chemical composition of both green and roasted coffee beans. The next part sums up the current knowledge of biologically active substances that can be found in coffee and their effect on human health. The main focus has been put on phenolic compounds and their antioxidant properties. The last chapter of the theoretical part tells of modern ways which are used to define phenolic compounds. The practical part of the thesis identifies phenolic compounds in coffee beans of two kinds, Coffea arabica and Coffea canephora, roasted at different temperatures and in the range from very raw beans to over-roasted ones. A highly efficient High Performance Liquid Chromatography in connection with Mass Spectrometry has been used to detect the most significant phenolic compounds.

The thesis deals with monitoring of ascorbic acid and other substances in selected fruit drinks. The theoretical part begins with a summary of knowledge about the occurrence and importance of ascorbic acid and their physiological effects. Furthermore, the content of vitamin C in individual fruits is compared. The following part deals with the division of soft drinks and raw materials, used for the production of soft fruit drinks. Part of the thesis is focused on the technology of fruit juice production obtained by direct pressing of fruit material and technology of fruit drinks production from fruit concentrates. The practical part is focused on determination of vitamin C concentration as well as vitamins of group B (B1, B2, B3, B5, B6) and organic acids (citramic acid, citric acid, malic acid, pyruvic acid and succinic acid) in samples of direct fruit juices and juice from concentrate. Mass spectrometer-coupled high-performance liquid chromatography (HPLC-MS) was used to detect vitamin C and other substances.

The thesis on Monitoring alkaloids in tomatoes describes a group of alkaloids and also some of them. The thesis focuses on the Solanaceae family, especially the tomato plant, tomato production, important substances and their influence on human health. The thesis presents information about tomato products and their quality which is influenced by the general material. Furthermore, separative and identification methods which can qualify alkaloids are described. In the practical part of the thesis the content of alkaloids in whole tomato plant is found out qualitatively by DESI and DART technic, the amount of the present alkaloids in unripe fruit, semi-ripe fruit and ripe fruit quantitatively by High Performance Liquid Chromatography connected with Mass Spectrometry (HPLC/MS). The volume of alkaloids in tomato juice, ketchup and tomato paste are determined.

Tumors of the adrenal gland belong to the most frequent neoplasms in humans with a prevalence of 3–10 % in adults. The aim of the diagnostic workup is the identification of potentially hormone-secreting and / or malignant tumors, because most of these tumors will require surgical resection. Malignant adrenocortical carcinomas (ACC) are very rare and associated with a poor prognosis in advanced stages, therefore, an early and accurate diagnosis is crucial. Within this thesis, two liquid chromatography tandem mass spectrometry (LC-MS/MS) methods for the quantification of steroids in different biomaterials were developed to improve the diagnostic workup of adrenal tumors. First, an LC-MS/MS method for the simultaneous quantification of cortisol and dexamethasone in serum samples after dexamethasone suppression test (DST) was developed, validated, and applied to 400 clinical samples. Newly established method-specific threshold concentrations for cortisol and dexamethasone increased DST specificity from 67.5 % to 92.4 % while preserving 100 % sensitivity. Second, an LC-MS/MS method for the quantification of eleven urinary steroids was developed and validated to improve the differentiation between ACC and adrenocortical adenomas (ACA). A decision tree requiring only two steroids was trained for classification and tested based on 24 h urine samples from 268 patients with adrenal tumor. Malignancy was excluded with a negative predictive value of 100 % in an independent validation cohort of 84 samples of 24-h urine. A newly proposed simplified diagnostic workflow with urinary steroid profiling as first tier test could obviate additional adrenal-specific imaging in 42 of 64 patients with ACA. The new DST method is already in clinical use at the University Hospital Würzburg, whereas the classification model based on urinary steroid profiling will require prospective validation in a larger cohort. / Nebennierentumoren gehören zu den häufigsten Neoplasmen beim Menschen und treten mit einer Prävalenz von 3–10 % bei Erwachsenen über 50 Jahren auf. Häufig wird die Raumforderung zufällig im Rahmen einer bildgebenden Untersuchung erkannt. Die meisten dieser sogenannten Inzidentalome sind gutartige und hormoninaktive Nebennierenrindenadenome (ACA), die keine therapeutische Intervention erfordern. Das Ziel der Nebennierentumor-Diagnostik ist die Abklärung potentieller Hormonaktivität und Malignität, denn diese Tumoren müssen zum Großteil operativ entfernt werden. Hormonaktive Tumoren können benigne oder maligne sein und sind durch die autonome Sekretion von Steroidhormonen charakterisiert. Maligne Nebennierenrindenkarzinome (ACC) sind sehr selten, aber aggressiv und mit einer schlechten Prognose im fortgeschrittenen Tumorstadium assoziiert. Da die therapeutischen Möglichkeiten für das ACC limitiert sind, ist eine schnelle und sichere Diagnostik erforderlich. Im Rahmen dieser Doktorarbeit wurden zwei Flüssigchromatographie-Tandemmassenspektrometrie (LC-MS/MS) Methoden zur Quantifizierung von Steroiden in Biomaterialien entwickelt, um damit die Diagnostik von Nebennierentumoren zu verbessern. Der 1 mg-Dexamethason-Hemmtest (DST) ist ein häufig durchgeführter Screening-Test zur Untersuchung auf autonome Cortisolsekretion. Dabei wird die Supprimierbarkeit der Cortisolsekretion durch die orale Einnahme von Dexamethason überprüft. Eine LC-MS/MS Methode zur simultanen Quantifizierung von Cortisol und Dexamethason im Serum wurde entwickelt, validiert und zur Messung von 400 DST-Patientenproben genutzt. Durch methodenspezifische Schwellenwertkonzentrationen für Cortisol und Dexamethason konnte die klinische Testspezifität von 67.5 % auf 92.4 % bei unveränderter Sensitivität von 100.0 % erhöht werden. Der zweite Teil dieser Arbeit befasst sich mit der Verbesserung der Unterscheidung von ACC und ACA. Dafür wurde eine LC-MS/MS Methode zur Quantifizierung von elf Steroiden im Urin entwickelt und validiert. Über die Messung von 24 h Sammelurinproben von 268 Nebennierenrindentumor-Patienten wurde ein Klassifikationsmodell, das auf nur zwei Steroiden basiert, trainiert und getestet. Sowohl die analytische Methode als auch das Klassifikationsmodell wurden hinsichtlich Robustheit und Zeiteffizienz optimiert, um sich möglichst gut in die klinische Routine implementieren zu lassen. Außerdem lag der Fokus auf einer einfachen, nachvollziehbaren und direkten Datenauswertung und -interpretation. Als ein Hauptergebnis konnte Malignität in einer unabhängigen Validierungskohorte von 84 Patienten mit einem negativen prädiktiven Wert von 100 % ausgeschlossen werden. Nach einem vereinfachten diagnostischen Schema mit der Urin-Steroid-Analytik als erstem Screening-Test könnte bei 42 von 64 Patienten mit ACA auf eine zusätzliche nebennierenspezifische Bildgebung verzichtet werden. Des Weiteren wurden erstmals Spontanurinproben als Surrogatmatrix für 24 h Sammelurin in der Validierungskohorte getestet. Dabei unterschied sich der positive prädiktive Wert der Spontanurine mit 86.7 % kaum von den 87.5 % der 24-h Sammelurine, während auch mit Spontanurin ein negativer prädiktiver Wert von 100 % erzielt werden konnte, was einen wichtigen Schritt in die Richtung einer vereinfachten Probensammlung darstellt. Sowohl die simultane Quantifizierung von Cortisol und Dexamethason als auch die 24-h Urin-Steroid-Methode haben ihre Eignung für die klinische Routineanwendung bewiesen. Der Transfer der Urinmethode auf den deutlich einfacheren Spontanurin erfordert jedoch eine prospektive Validierung in einer größeren Patientenkohorte. Die neue DST-Methode wurde bereits im September 2021 in die klinische Routine am Universitätsklinikum Würzburg eingeführt.

En marge d'expériences actuelles visant à développer une méthodologie analytique sur la pharmacocinétique-pharmacodynamique de la N-acétyl-cystéine (NAC) en prévention de la néphropathie liée à l'exposition aux substances de contraste (NESC), une mesure de la clairance des substances de contraste a été mise au point comme marqueur de filtration glomérulaire (FG) étant donné que celles-ci sont totalement éliminées par FG. Ainsi, la mesure de la FG a été déterminée par la clairance de l'iohexol, substance de contraste utilisée en imagerie médicale. L'originalité de ce projet est triple: (1) mesurer la clairance de l'iohexol (Omnipaque) chez des patients recevant également de l'iodixanol (Visipaque), substance de contraste de plus en plus utilisée; (2) explorer la mesure de la clairance d'iodixanol et (3) utiliser la spectrométrie de masse couplée à la chromatographie liquide, qui depuis les dernières années s'est taillée une place de plus en plus importante, pour le dosage de l'iohexol et de l'iodixanol. Le projet actuel s'est déroulé chez 17 sujets avec divers niveaux de fonction rénale devant subir des examens d'imagerie avec des substances de contraste. Une dose-traceur d'iohexol (5 ml) a été co-administrée avec l'iodixanol (environ 95 ml). Des spécimens sanguins ont été obtenus 0, 1, 2, 3, 4, 8 et 24 heures post-imagerie pour mesurer les clairances de l'iohexol et de l'iodixanol. Le comportement des autres marqueurs conventionnels de FG, soit le taux créatinine plasmatique et la clairance de la créatinine, ainsi que la clairance de la cystatine C et la clairance d'iodixanol ont été comparés à la clairance d'iohexol. Par conséquent, un protocole scientifique par HPLC-MSD Tof a été développé afin de séparer et de quantifier les molécules iohexol et iodixanol co-administrées dans le plasma des sujets. Les mesures des taux plasmatiques de ces deux molécules ont permis de déterminer par des calculs pharmacocinétiques que la clairance de l'iohexol discrimine bien la fonction rénale des sujets avec une fonction rénale normale de ceux avec une fonction rénale diminuée. De plus, il a été démontré qu'une seule mesure post-4 heures est suffisante pour diagnostiquer l'état de la fonction rénale d'un patient qui a subi une intervention demandant une exposition aux substances de contraste. Les corrélations entre la clairance de l'iohexol et d'autres marqueurs conventionnels de FG ainsi que celle de l'iodixanol ont illustré que la clairance de la créatinine calculée soit par l'équation MDRD (r = 0,714 et p = 0,001) ou par Cockcroft et Gault (r = 0,518 et p = 0,033) et la clairance de la cystatine C (r = 0,671 et p = 0,003) corrèlaient de manière significative avec l'étalon d'or, soit la clairance de l'iohexol. C'est pourquoi, il pourrait être possible de se fier à la mesure de la clairance de l'iohexol comme meilleur marqueur de FG afin de prévenir, de diagnostiquer et de traiter la NESC. De plus, des expériences scientifiques en recherche fondamentale pourront enfin être menées pour déterminer la relation pharmacodynamique- pharmacocinétique de la N-acétylcystéine dans la prévention de la NESC à l'aide de la mesure de la clairance de l'iohexol comme marqueur fiable de la FG. Enfin, les mécanismes d'action qui interviennent dans la NESC pourront être mieux évalués.

As micotoxinas são compostos produzidos por fungos, sendo potencialmente perigosos à saúde humana e animal. A Ocratoxina A (OTA) é uma das micotoxinas mais amplamente estudadas, sendo encontrada em várias matrizes alimentícias. A concentração dessa micotoxina nos alimentos é geralmente muito baixa (da ordem de ng g-1), sendo, portanto, necessário o emprego de técnicas de preparo de amostras que realizem a purificação e pré-concentração no analito. Os métodos de separação e detecção empregados na análise de OTA também devem oferecer sensibilidade adequada para a quantificação do analito. Logo, os objetivos do trabalho foram desenvolver uma metodologia utilizando a técnica in-tube SPME no modo de extração única (flow through extraction) com partículas de C18 como fase extratora e separação e detecção por HPLC-MS/MS. Além disso, otimizar e validar a metodologia proposta e detectar e quantificar a OTA em amostras de vinho. Para isso, a técnica in-tube SPME foi configurada e um tubo de PEEK foi empacotado com partículas de C18, o qual foi utilizado na extração. A otimização do método foi realizada utilizando-se um planejamento experimental composto central 22 + 3 pontos centrais, tendo como fatores a porcentagem de ACN e o tempo durante o carregamento da amostra. A validação da metodologia empregada foi realizada conforme o guia de validação da ANVISA e, posteriormente, amostras de vinho tinto seco e vinho branco seco foram analisadas. O método proposto foi desenvolvido, tendo sua funcionalidade atestada e suas condições de análise melhoradas, sendo utilizado 22 % de ACN e 6 minutos no carregamento da amostra. O método foi validado, mostrando sensibilidade adequada, com limites de detecção e quantificação iguais à 0,02 e 0,05 µg L-1, respectivamente. A linearidade e precisão da metodologia foram avaliadas, apresentando coeficiente de correlação igual a 0,996 e DPR menor que 6%, respectivamente. O método mostrou-se exato nos níveis de concentração médio e alto e a recuperação máxima obtida para o nível alto foi próximo 73%. Amostras brasileiras e estrangeiras de vinho tinto seco e vinho tinto seco branco foram analisadas e a OTA não foi detectada em nenhuma delas. Entretanto, a OTA pode essa estar presente nas amostras analisadas em concentrações mais baixas que as determinadas pelos limites de detecção e quantificação, não sendo potencialmente perigosos à saúde. / Mycotoxins are compounds produced by fungus, being a potential danger to human and animal health. Ochratoxin A (OTA) is a mycotoxin widely studied, being found in a varied of food matrices. OTA concentration in food is generally low (the order of ng g-1), being, therefore, necessary the use of sample preparation techniques to perform the analyte purification and preconcentration in the sample. The separation and detection methods used in OTA analysis also should offer proper sensibility in order to quantify the analyte adequately. In short, the goals of the present work were to develop a methodology using in-tube SPME in flow through extraction mode with C18 particles as extraction phase and separation and detection by HPLC-MS/MS. Further, optimize and validate the proposed methodology and detect and quantify OTA in wine samples. For this, in-tube SPME was configured and a PEEK tube was packed with C18 particles, which was used in the extraction step. The method optimization was achieved using a central composite 22 + 3 central points experimental design, having as factors the percentage of ACN and time during sample loading step. Validation method was done following ANVISA validation guide after which red dry wine and white dry wine samples were analyzed. The proposed method was developed, having its functionalities attested and its analysis conditions enhanced, using 22% of ACN and 6 minutes in sample loading. The method was validated, demonstrating proper sensitivity, with detection and quantification limits equal to 0.02 and 0.05 µg L-1, respectively. Linearity and precision were evaluated, exhibiting correlation coefficient equal to 0,996 e RSD under 6%, respectively. The method was accurate in medium and high concentration levels and maximum recovery was 73% in high concentration level. Brazilian and foreign red dry wine and white dry wine samples were analyzed and OTA was not detected in any of them. However, OTA may be present in samples analyzed in lower concentrations than that ones determined by detection and quantification limits, not being a potential danger to human health.

As micotoxinas são compostos produzidos por fungos, sendo potencialmente perigosos à saúde humana e animal. A Ocratoxina A (OTA) é uma das micotoxinas mais amplamente estudadas, sendo encontrada em várias matrizes alimentícias. A concentração dessa micotoxina nos alimentos é geralmente muito baixa (da ordem de ng g-1), sendo, portanto, necessário o emprego de técnicas de preparo de amostras que realizem a purificação e pré-concentração no analito. Os métodos de separação e detecção empregados na análise de OTA também devem oferecer sensibilidade adequada para a quantificação do analito. Logo, os objetivos do trabalho foram desenvolver uma metodologia utilizando a técnica in-tube SPME no modo de extração única (flow through extraction) com partículas de C18 como fase extratora e separação e detecção por HPLC-MS/MS. Além disso, otimizar e validar a metodologia proposta e detectar e quantificar a OTA em amostras de vinho. Para isso, a técnica in-tube SPME foi configurada e um tubo de PEEK foi empacotado com partículas de C18, o qual foi utilizado na extração. A otimização do método foi realizada utilizando-se um planejamento experimental composto central 22 + 3 pontos centrais, tendo como fatores a porcentagem de ACN e o tempo durante o carregamento da amostra. A validação da metodologia empregada foi realizada conforme o guia de validação da ANVISA e, posteriormente, amostras de vinho tinto seco e vinho branco seco foram analisadas. O método proposto foi desenvolvido, tendo sua funcionalidade atestada e suas condições de análise melhoradas, sendo utilizado 22 % de ACN e 6 minutos no carregamento da amostra. O método foi validado, mostrando sensibilidade adequada, com limites de detecção e quantificação iguais à 0,02 e 0,05 µg L-1, respectivamente. A linearidade e precisão da metodologia foram avaliadas, apresentando coeficiente de correlação igual a 0,996 e DPR menor que 6%, respectivamente. O método mostrou-se exato nos níveis de concentração médio e alto e a recuperação máxima obtida para o nível alto foi próximo 73%. Amostras brasileiras e estrangeiras de vinho tinto seco e vinho tinto seco branco foram analisadas e a OTA não foi detectada em nenhuma delas. Entretanto, a OTA pode essa estar presente nas amostras analisadas em concentrações mais baixas que as determinadas pelos limites de detecção e quantificação, não sendo potencialmente perigosos à saúde. / Mycotoxins are compounds produced by fungus, being a potential danger to human and animal health. Ochratoxin A (OTA) is a mycotoxin widely studied, being found in a varied of food matrices. OTA concentration in food is generally low (the order of ng g-1), being, therefore, necessary the use of sample preparation techniques to perform the analyte purification and preconcentration in the sample. The separation and detection methods used in OTA analysis also should offer proper sensibility in order to quantify the analyte adequately. In short, the goals of the present work were to develop a methodology using in-tube SPME in flow through extraction mode with C18 particles as extraction phase and separation and detection by HPLC-MS/MS. Further, optimize and validate the proposed methodology and detect and quantify OTA in wine samples. For this, in-tube SPME was configured and a PEEK tube was packed with C18 particles, which was used in the extraction step. The method optimization was achieved using a central composite 22 + 3 central points experimental design, having as factors the percentage of ACN and time during sample loading step. Validation method was done following ANVISA validation guide after which red dry wine and white dry wine samples were analyzed. The proposed method was developed, having its functionalities attested and its analysis conditions enhanced, using 22% of ACN and 6 minutes in sample loading. The method was validated, demonstrating proper sensitivity, with detection and quantification limits equal to 0.02 and 0.05 µg L-1, respectively. Linearity and precision were evaluated, exhibiting correlation coefficient equal to 0,996 e RSD under 6%, respectively. The method was accurate in medium and high concentration levels and maximum recovery was 73% in high concentration level. Brazilian and foreign red dry wine and white dry wine samples were analyzed and OTA was not detected in any of them. However, OTA may be present in samples analyzed in lower concentrations than that ones determined by detection and quantification limits, not being a potential danger to human health.

Les floculants à base de polyacrylamide (PAM) sont produits à partir du monomère toxique : l’acrylamide (AMD) et peuvent en contenir des quantités résiduelles (jusqu’à 0,1% en Europe). Après utilisation pour faciliter la séparation solide/liquide des eaux de procédés dans les industries de granulat, ces floculants sont stockés avec les boues de décantation dans des lagunes à partir desquelles une dissémination de l’AMD et du PAM vers les eaux de surface ou les eaux souterraines peut avoir lieu. Dans ces travaux de thèse, les interactions du PAM et de l’AMD avec des particules de boue et des phases argileuses (kaolinite et illite, utilisées pour étanchéifier les lagunes de décantation) ont été étudiées. Pour pouvoir quantifier correctement l’AMD, une méthode d’analyse basée sur la HPLC/MS/MS en injection directe a été développée. Cette méthode a été validée avec les normes Afnor NF T 90-210 et NF T 90-220 avec une limite de quantification égale à 1 µg/L. L’étude de l’interaction de l’AMD avec des particules de boue d’un site de granulat et deux argiles (kaolinite et illite) a mis en évidence une faible adsorption de l’AMD sur ces phases solides (<10%), indépendante du temps, de la concentration en AMD et du pH. Inversement, le PAM s’adsorbe fortement et irréversiblement sur la boue, la kaolinite et l’illite avec une cinétique rapide de 1er ordre. Les isothermes d’adsorption sont bien corrélées avec les modèles de Langmuir et de Freundlich. Les quantités d’adsorption du PAM sont indépendantes du pH des suspensions mais fortement impactées par la force ionique qui influence les interactions électrostatiques entre le PAM et les surfaces solides. / Polyacrylamide (PAM) based floculants are produced from the highly toxic acrylamide (AMD) monomer and can contain residual amounts (up to 0.1% in Europe) of AMD. After they are used to facilitate liquid/solid separation of process water in aggregate quarries, PAM floculants are stored, with the sewage sludge, in decantation lagoons. Dissemination of AMD and PAM to groundwater and surface water from these lagoons can occur. In this work, we aimed to study the interactions of AMD and PAM with sludge particles and clays (kaolinite and illite used for decantation lagoon sealing) from aggregate quarry. To correctly quantify the AMD, analytical method based on HPLC/MS/MS with direct injection was developed. This method was validated according to the Afnor guidelines (NF T 90-210 and NF T 90-220) with a limit of quantification of 1 µg/L. Results of AMD adsorption experiments showed a low adsorption of AMD to sludge and clay (kaolinite and illite) particles, which is independent of time, AMD concentration and pH. Inversely, PAM was found to adsorb strongly and irreversibly to sludge, kaolinite and illite with a rapid kinetic of adsorption which consists of first order kinetic. Adsorption isotherms are well correlated with Langmuir and Freundlich models. PAM adsorption quantities are independent on the pH of suspensions, but are strongly impacted by the ionic strength which affects electrostatic interactions between PAM and solid surfaces.

A oxidação do DNA por espécies reativas de oxigênio, como o oxigênio molecular singlete [O2 (1&#916;g)] , pode estar relacionada ao aparecimento de mutações e ao desenvolvimento de doenças. O O2 (1&#916;g) pode ser gerado biologicamente por reação de fotossensibilização, pela reação de H2O2 e HOCl e pela decomposição de peróxidos orgânicos contendo hidrogênio alfa (&#945;-ROOH), na presença de metais de transição (Fe2+, Cu2+) ou HOCl. A decomposição de &#945;-ROOH, como hidroperóxidos de lipídeos ou proteínas na presença de metais de transição, pode gerar O2 (1&#916;g) via mecanismo de Russell. Neste mecanismo, a oxidação de &#945; -ROOH gera radicais peroxila, que podem reagir entre si, formando um intermediário tetraóxido linear. Este intermediário tetraóxido linear pode decompor através de um mecanismo cíclico e produzir O2 (1&#916;g), um álcool e um composto carbonílico. Como a decomposição de &#945;-ROOH pelo mecanismo de Russell pode ser uma importante fonte biológica de O2 (1&#916;g) decidimos investigar se o &#945;-hidroperóxido de timina, 5-(hidroperoximetil)uracil (5-HMPU), poderia gerar esta espécie reativa na presença de metais (Ce4+, Fe2+, Cu2+) e HOCl. Outro objetivo foi avaliar os efeitos oxidativos, em DNA plasmidial (pBR322), da decomposição de 5-HPMU na presença de Cu2+. A geração de O2 (1&#916;g) na reação de 5-HPMU e Ce4+ ou HOCl foi demonstrada por meio do monitoramento da emissão de luz monomolecular de O2 (1&#916;g) na região do infravermelho próximo (IR-próximo, &#955; = 1270 nm) e bimolecular na região do visível (&#955; = 634 e 703 nm). A aquisição do espectro de emissão de O2 (1&#916;g) forneceu evidências inequívocas da geração desta espécie reativa na reação de 5-HPMU e Ce4+ ou HOCl. Além disto, a formação de O2 (1&#916;g) na reação de 5-HPMU e Fe2+, Cu2+ ou HOCl foi demonstrada através da captação química de O2 (1&#916;g) utilizando 9,10- divinilsulfonatoantraceno (AVS) e detecção por HPLC/MS/MS do endoperóxido (AVSO2) formado. A detecção por HPLC/MS/MS dos produtos de decomposição de 5-HPMU, 5- (hidroximetil)uracila (5-HMU) e 5-formiluracila (5-FoU), reforçaram a hipótese de geração de O2 (1&#916;g) pelo mecanismo de Russell. A análise dos resultados da incubação de pBR322, 5-HPMU e crescente concentração de Cu2+ mostraram o aumento da forma circular aberta (OC), indicando a formação de quebra de fita simples do DNA, provavelmente proveniente da presença dos radicais peroxila e alcoxila de 5-HPMU. Já a utilização das enzimas de reparo FPG e NTH na incubação de pBR322, 5-HPMU e Cu2+ forneceu evidências da formação preferencial de purinas oxidadas, especialmente de 2&#8217;-desoxiguanosina (dGuo). O aumento significativo da forma OC na presença de FPG indicou a formação de 8-oxo-2&#8217;-desoxiguanosina, resultante da oxidação da dGuo por O2 (1&#916;g) e/ou pelos radicais derivados de 5-HPMU. Podemos concluir que 5-HPMU pode ser uma importante fonte biológica de O2 (1&#916;g) . Além disto, a presença de 5-HPMU pode levar a propagação dos danos oxidativos no DNA, pois sua decomposição pode gerar radicais peroxila e alcoxila / Oxidation of DNA by singlet molecular oxygen O2 (1&#916;g) can be involved in the development of mutations and diseases. In vivo, O2 (1&#916;g) can be generated by photosensitization reaction, H2O2 and HOCl reaction and decomposition of organic hydroperoxides with &#945;-hydrogen (&#945;-ROOH) in the presence of metal ions (Fe2+, Cu2+) or HOCl. The &#945;-ROOH decomposition, such as lipid or protein hydroperoxides in the presence of metal ions or HOCl can generate O2 (1&#916;g) by Russell mechanism. In this mechanism, the self-reaction of peroxyl radicals generates a linear tetraoxide intermediate that decomposes to O2 (1&#916;g) , an alcohol and an aldehyde. Therefore, the purpose of this work is to investigate if O2 (1&#916;g) can be generated by &#945;-thymine hydroperoxide, 5- (hydroperoxymethyl)uracil (5-HPMU) in the presence of Ce4+, Fe2+, Cu2+ or HOCl. Another purpose is to study base modification and strand breaks formation in plasmid DNA (pBR322) by 5-HPMU decomposition in the presence of Cu2+. The generation of O2 (1&#916;g) in the reaction of 5- HPMU and Ce4+ or HOCl was monitored by monomol light emission in the near-infrared region (NIR, &#955; = 1270 nm) and dimol light emission in the visible region (&#955; = 634 e 703 nm). The generation of O2 (1&#916;g) during the reaction of 5-HPMU and Ce4+ or HOCl was confirmed by acquisition of the light emission spectrum in the NIR. Furthermore, the generation of O2 (1&#916;g) produced by 5-HPMU and Fe2+, Cu2+ or HOCl was also confirmed by chemical trapping using anthracene-9,10-divinylsulfonate (AVS) and HPLC/MS/MS detection of the corresponding endoperoxide (AVSO2). The detection by HPLC/MS/MS of 5-(hydroxymethyl)uracil (5-HMU) and 5-formyluracil (5-FoU), two 5-HPMU decomposition products, support the Russell mechanism. Plasmid results from pBR322, 5-HPMU and Cu2+ reaction showed formation of DNA open circular form (OC), probably produced by 5-HPMU peroxyl and alkoxyl radicals. Additionally, the reaction of pBR322, 5-HPMU and Cu2+ following by Fpg and NTH enzyme treatment demonstrated evidences of purine modification, especially 2&#8217;-deoxyguanosine (dGuo). The use of FPG enzyme indicated the formation of 8-oxo-7,8-dihydro-2&#8217;-deoxyguanosine, a dGuo oxidation product formed by O2 (1&#916;g) and/or 5-HPMU peroxyl and alkoxyl radicals. We can conclude that 5-HPMU can be a biological source of O2 (1&#916;g)] and 5-HPMU decomposition can lead to an enhancing of DNA oxidative damage by 5-HPMU peroxyl and alkoxyl radicals formation