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Knight, S. J. "Separation and identification of RA2000 photographic developing solution components using LC, LC-MS and LC-MS-MS techniques". Thesis, Swansea University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637812.
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The analysis of photographic developing solutions presents an interesting and challenging problem for the analytical chemist. The developing agents themselves contain a wide range of components of various different chemistries, both inorganic and organic components are present at a wide range of concentrations. The developing agents as well has having a complex chemistry of their own, on use, are further complicated by the formation of products which can further affect the developing solutions performance. This work uses a variety of chromatographic and mass spectrometric techniques to examine a range of compounds present in the black and white Kodak developer RA2000. Emphasis is given to the application of these techniques to solving the analytical problem. The first chapter gives a theoretical introduction to mass spectrometry and liquid chromatography, with a discussion on the general principles in interfacing the two techniques. Chapter two gives a theoretical introduction to photography as well as an in depth discussion of developing solutions, specifically the RA2000 black and white developing solution. Analysis of RA2000 by liquid chromatography and capillary electrophoresis is also described. Chapter three provides an in depth discussion of solid phase extraction techniques as an alternative sample preparation method to liquid / liquid solvent extraction. Analysis of RA2000 by solid phase extraction and liquid chromatography was carried out in an attempt to concentrate the components formed after use, as well as to try and separate out the heavily concentrated compounds. Chapter four describes the analysis of RA2000 by liquid chromatography-thermospray-mass spectrometry and liquid chromatography-particle beam-mass spectrometry. An in depth discussion of both techniques is given. A column switching arrangement was used to allow analysis of the lower concentration components.
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Müller, Claudia. "Entwicklung von Screeningverfahren für Arzneistoffe und Metaboliten mittels LC-MS und LC-MS-MS". [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972115633.
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Seiwert, Bettina. "Ferro-based derivatizing agents for LC/MS an LC/EC/MS". Enschede : University of Twente [Host], 2007. http://doc.utwente.nl/57888.
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Gong, H. "Studies of nucleobases, nucleosides and nucleotides by LC, CZE, LC-MS, CZE-MS and MS techniques". Thesis, Swansea University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637073.
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This work employs RP-HPLC and CE separation techniques, soft ionisation MS techniques (ESI and APCI), and on-line LC/MS, CE/MS and MS/MS techniques to analyse both the standards and nucleic acid constituents in mice livers. Emphasis is given to the method developments and the application of these techniques to tackle and solve biological and chemical problem. Chapter one gives an introduction to mass spectrometry, liquid chromatography and its separation modes, and also introduces and discusses several LC/MS interfaces based on their advantages, restrictions and their applications. Chapter two introduces capillary electrophoresis, its separation modes and CE/MS interfacing techniques with discussion of both sheath-liquid based on sheathless based CE/ME interfaces. Chapter three describes the analysis of nucleobases, nucleosides and nucleotide standards and nucleic acid constituents of the mice livers by on-line LC-APCI/MS and tandem MS/MS techniques, LSQ ion-trap and TSQ 700 were used to carry out the work above. Chapter four investigates fully and characterizes nucleobases, nucleosides, nucleotides and their isomers in several solvent systems by electrospray mass spectrometry (ES/MS). Develops analytical methods with LC-ES/MS, LC/MS/MS techniques and applies these techniques to examine the standards and identify several nucleobases, nucleosides and nucleotides in mice livers. Chapter five describes separation methods for nucleobases, nucleosides and nucleotides and their isomers by capillary electrophoresis with both uncoated silica combination techniques were employed to analyse standards of nucleobases, nucleosides, nucleotides and their isomers; and to analyse nucleic acid constituents in mice livers. Chapter six gives the conclusions and further research work in future. The relative merits of the use of LC-APCI/MS, LC-ESI/MS and CZE/MS techniques for the studies of nucleic acid constituents are compared.
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Hellmuth, Christian. "LC-MS/MS applications in Targeted Clinical Metabolomics". Diss., Ludwig-Maximilians-Universität München, 2014. http://nbn-resolving.de/urn:nbn:de:bvb:19-168254.
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Leavens, W. J. "Chemical derivatisation for LC-MS". Thesis, Swansea University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637863.
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The investigation of the chemical derivatisation of low molecular weight compounds containing carboxylic acid, amine, alcohol, aldehyde or ketone functional groups by novel reagents designed to enhance their response by liquid chromatography-electrospray ionisation mass spectrometry (LC-ESI/MS) is described. A series of novel reagents containing functionalised ferrocene or tris(2,4,6-trimethoxyphenyl)phosphonium (TMPP) moieties were synthesised for pre-column derivatisation of the target analytes. The ferrocene reagents enabled facile electrospray ionisation, through formation of the molecular cation or the protonated molecular ion, whilst the TMPP reagents provided a molecular cation (or "pre-charged" species). Additionally, the ferrocene reagents provided an elemental tag to facilitate analysis of the derivative by inductively coupled plasma mass spectrometry (ICP/MS). Carboxylic acids were activated by chloromethylpyridinium iodide in the presence of an organic base or by a water-soluble carbodiimide and reacted with an amine to produce a stable amide linkage. Both carboxylic acid and amine-containing analogues of ferrocene and TMPP were synthesised for use with this coupling reaction. Derivatisation of aldehydes and ketones was achieved by reaction of hydrazino analogues of TMPP to form hydrazone derivatives. Additionally, derivatisation was also achieved through the use of activated esters of ferrocene and TMPP and their nucleophilic displacement reaction with amines.
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Castelazo, Anahi Santoyo. "Comprehensive folate profiling in plants using LC-MS/MS". Thesis, University of Nottingham, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.508152.
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Geiger, Armin Guntram. "Network-based contextualisation of LC-MS/MS proteomics data". Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/96116.
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Thesis (MSc)--Stellenbosch University, 2014.ENGLISH ABSTRACT: This thesis explores the use of networks as a means to visualise, interpret and mine MS-based proteomics data. A network-based approach was applied to a quantitative, cross-species LCMS/ MS dataset derived from two yeast species, namely Saccharomyces cere- visiae strain VIN13 and Saccharomyces paradoxus strain RO88. In order to identify and quantify proteins from the mass spectra, a workflow consisting of both custom-built and existing programs was assembled. Networks which place the identifed proteins in several biological contexts were then constructed. The contexts included sequence similarity to other proteins, ontological descriptions, proteins-protein interactions, metabolic pathways and cellular location. The contextual, network-based representations of the proteins proved effective for identifying trends and patterns in the data that may otherwise have been obscured. Moreover, by bringing the experimentally derived data together with multiple, extant biological resources, the networks represented the data in a manner that better represents the interconnected biological system from which the samples were derived. Both existing and new hypotheses based on proteins relating to the yeast cell wall and proteins of putative oenological potential were investigated. These proteins were investigated in light of their differential expression between the two yeast species. Examples of proteins that were investigated included cell wall proteins such as GGP1 and SCW4. Proteins with putative oenological potential included haze protection factor proteins such as HPF2. Furthermore, differences in capacity for maloethanolic fermentation between the two strains were also investigated in light of the protein data. The network-based representations also allowed new hypotheses to be formed around proteins that were identified in the dataset, but were of unknown function.
AFRIKAANSE OPSOMMING: Hierdie studie verken die gebruik van netwerke om proteonomiese data te visualiseer, te interpreteer en te ontgin. 'n Netwerkgebaseerde benadering is gevolg ter ontleding van 'n kwantitatiewe LC-MS/MS datastel wat afkomstig was van twee gis-spesies nl, Saccharomyces cerevisiae ras VIN1 en Saccharomyces paradoxus ras RO88. Die massaspektra is met bestaande en selfgeskrewe rekenaarprogramme verwerk om 'n werkvloei saam te stel ter identifisering en kwantifisering van die betrokke proteïene. Hierdie proteïene is dan aan bestaande biologiese databasisse gekoppel om die proteïene in biologiese konteks te plaas. Die gekontekstualiseerde is dan gebruik om biologiese netwerke van die data te bou. Die kontekste beskou onder meer lokalisering van selaktiwiteite, ontologiese beskrywings, ooreenkomste in aminosuur-volgordes en interaksies met bekende proteïene asook assosiasie en verbintenisse met metaboliese paaie. Hierdie kontekstuele, netwerk-gebaseerde voorstelling van die betrokke prote- ïene het effektief duidelike data-tendense en patrone opgelewer wat andersins nie opmerkbaar sou wees nie. Daarby het die kombinering van eksperimentele data en bestaande biologiese bronne 'n beter perspektief aan die data-analise verleen. Beide bestaande en nuwe hipoteses tov gis-selwandproteïene en prote ïene met moontlike wynkundige potensiaal is ondersoek in die lig van hul differensiële uitdrukking in die twee gis-spesies. Voorbeelde wat ondersoek is sluit in selwandproteïene soos GGP1 en SCW4 asook waasbeskermingsfaktorproteïen HPF2. Verskille tov kapasiteit mbt malo-etanoliese gisting is ook gevind. Die netwerk-gebaseerde voorstellings het ook aanleiding gegee tot die formulering van nuwe hipoteses mbt datastel-proteïene waarvan die funksies tans onbekend is.
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Harder, Ulrike. "Amino acid analysis in biofluids using LC-MS/MS". Diss., Ludwig-Maximilians-Universität München, 2014. http://nbn-resolving.de/urn:nbn:de:bvb:19-166180.
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Klinische Studien zeigen, dass die Zusammensetzung von zirkulierenden, freien AS im Blut, ein Marker für monogene und multigenetische Krankheiten ist. Die Analyse von hohen Probandenzahlen in klinischen Studien wird oftmals durch aufwendige und lange Probenaufarbeitungsschritte begrenzt. Im Rahmen der Metabolomics Plattform, die im Dr. von Haunerschen Kinderspitals etabliert wurde, wurde eine Hochdurchsatzmethode entwickelt, die eine selektive, sensitive, präzise und robuste Quantifizierung von 22 AS aus kleinen Probenvolumina ermöglicht. Im Laufe der Zeit konnten noch weitere Aminosäuren zur Methodik hinzugefügt werden. Dabei können innerhalb von 36 Stunden 96 Proben analysiert werden. Mit Hilfe eines deuterierten, interenen Standards in methanolischer Lösung werden Proteine aus nur 10 μL Probenvolumen gefällt. Zur Quantifizierung der AS wird anschliessend der eingedampfte Überstand derivatisiert und in Kombination mit einem Ionen-Paar- Reagenzes chromatographiert. Der Methodenaufarbeitung liegt eine umfassende und ausführliche Validierung zugrunde, die einer Interday Precision von 3.1 -10.8 % für alle Analyten erzielt. Zusätzlich unterzieht sich unsere Methode jedes Jahr an einem Ringversuch, der eine exakte Bestimmung aller Analyten gewährleistet.
Im Zusammenhang mit der Programmierung des Stoffwechsels durch die Ernährung im Säuglingsalter wurde die neu entwickelte AS-Methode zur Quantifizierung von 726 Serum Proben in einer randomizierten klinischen Studie eingesetzt. Dabei wurde der Bezug zwischen Proteinzufuhr (Formelnahrung mit hohem Eiweißanteil bzw. niedriegem Eiweißanteil) und AS-Profil bei 6 Monate alten Säuglingen analysiert. Eine signifikante Veränderung der Plasmakonzentrationen zeigte sich in der Gruppe der formelernährten Kindern mit hohem Proteinanteil für folgende AS: BCAA, Gly, Lys, Met, Phe, Pro, Thr, Trp und Tyr. Essentielle AS werden über die Nahrung aufgenommen und vermutlich über das L-Transportsystem in die Zirkulation freigesetzt. Im Vergleich dazu werden nicht essentielle AS im Darm katabolisiert und mit Hilfe der de novo Synthese in gleichbleibenden Konzentrationen reguliert, sodass kein signifikanter Unterschied in beiden Gruppen beobachtet wurde. Durch eine proteinreiche Nahrung können AS vermehrt an der Aktivierung von Wachstumshormonen (mTOR, IGF-1) teilhaben, was sich im vermehrten Zellwachstum und –proliferation manifestiert. Nichts desto trotz kann die vermehrte Wachstumshormonaktivierung Krankheiten wie Insulinresistenz, Diabetes oder auch Übergewicht hervorrufen. Aufgrund des erhöhten Krankheitsrisikos ist einerseits von einer proteinreichen Ernährung im frühen Säuglingsalter abzuraten, andererseits kann das Stillen bzw. eiweißänhnliche Brustmilchzusammensetzung gesundheitsunterstützend sein.
Auch im Rahmen eines Supplementierungsprojektes bei Kühen, hat sich die neu entwickelte AS-Methode bewährt. Dazu wurden jeweils 10 Kühe kurz vor und nach der Geburt mit CLA (CLA-Gruppe) oder mit Linolsäure (Kontroll-Gruppe) supplementiert. Ziel der Studie war es, den Zusammenhang zwischen CLA Supplementierung und AS- Profil im Blut zu analysieren. Dazu wurden zu insgesamt 8 Zeitpunkten vor und nach der Geburt, Blutproben entnommen. Es kristallisierten sich 3 verschiedene Zeitverläufe heraus, wobei die meisten AS-Konzentrationen nach der Geburt abfallen und langsam wieder auf ihre Ausgangswerte ansteigen. AS wie Glu sinken vor der Geburt stark ab, was dafür sprechen könnte, dass der Fetus mit ausreichend Glu versorgt wird und nach der Geburt vermehrt in die Milch transportiert wird. Gly, HPro, MHis und Ser steigen bis zur Geburt an und fallen dann wieder ab wobei Mhis durch den Muskelproteinabbau keinen Konzentrationsanstieg in den ersten 12 Laktationswochen erfährt. Die Supplementierung mit CLA zeigte keinen signifikanten Unterschied beider Gruppen auf das AS-Profil und zeigte somit keine Auswirkungen auf die AS-Synthese.Clinical studies show that the composition of circulating free AA in blood, are a marker for monogenetic and multigenetic diseases. The analysis of a large number of subjects in clinical trials is often limited by complicated and long sample preparation steps. As part of the metabolomics platform established at the Dr. von Hauner Children ́s Hospital, a high-throughput method was developed which allows a selective, sensitive, precise and robust quantification of 22 AA from very small sample volumes. Over time further AA were added to the methodology. All AA of 96 samples can be measured within 36 hours. Using an internal standard in methanolic solution proteins were precipitated from only 10 μL sample volume. For AA quantification, the evaporated supernatant is derivatized and analyzed with an ion-pair reagent. The methodology is based on a comprehensive and detailed validation with an interday precision of 3.1- 10.8% for all analytes. Every year we participate in a collaborative study which ensures an accurate determination of all analyses. In the context of early programming, the newly developed AA method was used for quantifying 726 serum samples in a randomized clinical trial. Here, the relation between different protein intake (formula with high or low protein content) and AA profiles at 6 month old infants was analyzed. A significant alteration in serum concentration was found in the HP group for following AA: BCAA, Gly, Lys, Met, Phe, Pro, Thr, Trp und Tyr. Essential AA were taken by nutrients and probably released from the L-transport system into circulation. In comparison, non essential AA are catabolized in the intestine and regulated by de novo synthesis in equal concentrations. Therefore, no significant difference of non essential AA was observed between HP and LP group. High protein diet leads to an activation of growth hormones (mTOR, IGF-1) by enhanced availability of AA which is manifested in increased cell growth and proliferation. Nevertheless, the increased hormone activation can causes diseases such as insulin resistance, diabetes or obesity. Because of the increased risk for diseases a high protein diet in early infancy is not recommended but breast feeding or low protein diet can have beneficial effects for health. Within a cow supplementation project, the newly developed AA method has proved effective. From two weeks before to nine weeks after expected calving one group (CLA group, n=10) was supplemented with CLA and one group (control group, n=10) was supplemented with linoleic acid. The aim of the study was to analyze the relation between CLA supplementation and AA profiles in blood samples. These were taken at a total of eight times before and after delivery. We observed three different time courses of AA. In most cases AA levels decreased after delivery and afterwards concentrations increased slowly to their initial values. Glu is decreased before delivery which may indicate that the fetus is supplied sufficient with Glu. After delivery Glu is increasingly transported in the milk. Gly, HPro, MHis and Ser increased after delivery and then moved back to basal values where MHis did not increase in the first 12 weeks due to muscle protein breakdown. CLA supplementation showed no significant difference between the two groups on the AA concentrations and thus showed no effect on AA synthesis.
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Couchman, Lewis. "LC-MS/MS analysis of buprenorphine and norbuprenorphine in urine". Thesis, Queen Mary, University of London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.511397.
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Moura, Eliel Rogério Rolim de. "Determinação de pesticidas no Rio Piquiri por LC/MS/MS". Universidade Tecnológica Federal do Paraná, 2013. http://repositorio.utfpr.edu.br/jspui/handle/1/841.
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A qualidade da água e preservação dos ambientes aquáticos assumiu papel fundamental para a sustentabilidade, não só relacionado ao abastecimento, mas também à preservação destes ecossistemas. O uso da água, especialmente para abastecimento dos centros urbanos e irrigação na agricultura tem favorecido a tendência à diminuição das reservas de águas limpas e consequentemente a menor diluição de poluentes presentes, entre eles os pesticidas. Os pesticidas fazem parte do grupo de poluentes que podem gerar impactos significativos nos ambientes em que são inseridos, impactos dos quais alguns ainda não são totalmente conhecidos. Em função do crescente aumento da demanda por alimentos e sua consequente necessidade de se obter maior produtividade, o uso de pesticidas tem aumentado significativamente favorecendo o aumento destes impactos. Este modelo agrícola de produção é predominante em todo o mundo e resulta na presença destes poluentes nos mais diversos ambientes aquáticos, especialmente os superficiais próximos a regiões de cultivo. Neste contexto, o monitoramento destes poluentes em campo indica seu destino nos ambientes próximos à sua aplicação demonstrando mais fielmente seu comportamento neles, bem como fornece informações de referência para programas de monitoramento e avaliação de pesticidas nestes ambientes. O presente estudo avaliou amostras de água e sedimento do Rio Piquiri, localizado em uma região de alta produção de trigo, soja e milho, no estado do Paraná, Brasil. Este rio sofre influência direta da aplicação de pesticidas das lavouras da região. As amostras de água foram extraídas com uma mistura de diclorometano:hexano e as amostras de sedimento com uma mistura de acetona:hexano, tendo sido concentradas 500 vezes para as amostras de água e 25 vezes para as de sedimento. Os extratos foram analisados em LC/MS/MS e confirmaram a presença dos herbicidas e fungicidas utilizados na região do estudo conforme dados oficiais de comercialização no período das coletas. Os resultados mais expressivos nas amostras de água foram do herbicida Atrazina, 0,030 μg L-1 e do fungicida Carbendazim, 0,178 μg L-1. No sedimento os maiores valores encontrados foram para os fungicidas Carbendazim 26,8 μg L-1 e Azoxistrobina, 0,712 μg L-1,
ambos na terceira coleta no ponto de coleta 3.Water quality and conservation of aquatic environments assumed a leading condition for sustainability, not only related to the supply, but also the preservation of these ecosystems. The use of water, especially for supply to urban centers and irrigation in agriculture has favored upon the decrease of the reserves of clean water and therefore less dilution of pollutants, including pesticides. Pesticides are among the group of pollutants that can generate significant impacts on environments in which they are entered, some of which impacts are not yet fully known. Due to the growing demand for food and the consequent need to achieve greater productivity, pesticide use has increased significantly favoring the increase f these impacts. This agricultural production system is prevalent in the world and results in the presence of such pollutants in various aquatic environments, especially the surface regions, near of crop areas. In this context, monitoring of these pollutants in the field indicates its fate in the environment near its application showing more accurately its behavior in field, and provides reference information for program monitoring and evaluation of pesticides in these environments. This study examined samples of water and sediment Piquiri River, located in a region of high production of wheat, soybeans and corn in the state of Paraná, Brazil. This river is under direct influence of the application of pesticides of the region. Water samples were extracted with a mixture of dichloromethane:hexane and sediment samples with acetone:hexane and was concentrated 500 times for water and 25 times for sediment. The extracts were analyzed by LC / MS / MS and confirmed the presence of herbicides and fungicides used in the study region according to official data of the marketing period of the collections. The most impressive results in the water samples were the herbicide Atrazine, 0,030 μg L-1 and the fungicide Carbendazim, 0,178 μg L-1. In the sediment, the highest values were found for the fungicide Carbendazim, 26.8 μg L-1 and Azoxystrobin, 0.712 μg L-1, both in the third collection at the collection point 3.
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Zhou, Bin. "Computational Analysis of LC-MS/MS Data for Metabolite Identification". Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/36109.
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Metabolomics aims at the detection and quantitation of metabolites within a biological system. As the most direct representation of phenotypic changes, metabolomics is an important component in system biology research. Recent development on high-resolution, high-accuracy mass spectrometers enables the simultaneous study of hundreds or even thousands of metabolites in one experiment. Liquid chromatography-mass spectrometry (LC-MS) is a commonly used instrument for metabolomic studies due to its high sensitivity and broad coverage of metabolome.
However, the identification of metabolites remains a bottle-neck for current metabolomic studies. This thesis focuses on utilizing computational approaches to improve the accuracy and efficiency for metabolite identification in LC-MS/MS-based metabolomic studies. First, an outlier screening approach is developed to identify those LC-MS runs with low analytical quality, so they will not adversely affect the identification of metabolites. The approach is computationally simple but effective, and does not depend on any preprocessing approach. Second, an integrated computational framework is proposed and implemented to improve the accuracy of metabolite identification and prioritize the multiple putative identifications of one peak in LC-MS data. Through the framework, peaks are likely to have the m/z values that can give appropriate putative identifications. And important guidance for the metabolite verification is provided by prioritizing the putative identifications. Third, an MS/MS
spectral matching algorithm is proposed based on support vector machine classification. The approach provides an improved retrieval performance in spectral matching, especially in the presence of data heterogeneity due to different instruments or experimental settings used during the MS/MS spectra acquisition.Master of Science
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Bodi, Dorina. "LC-MS/MS-Bestimmung von Kokzidiostatika in Futtermittel und Ei". Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2014. http://dx.doi.org/10.18452/16982.
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Kokzidiostatika werden in der Kleintiermast als Futtermittelzusatzstoffe zur Vorbeugung der Kokzidiose eingesetzt. Die Verwendung der Wirkstoffe ist in der Europäischen Union gesetzlich geregelt und unterliegt der amtlichen Lebens- und Futtermittelkontrolle. In der vorliegenden Arbeit wurden Methoden zur flüssigchromatographisch tandem-massen¬spektro¬metrischen (LC-MS/MS-) Bestimmung von Kokzidiostatika in Futtermitteln und in Ei entwickelt. Durch Bestandteile des Probenmaterials traten Störungen des Analytsignals auf. Die Untersuchung solcher Matrixeffekte ist in der pharmazeutischen und der Pestizidanalytik üblich. Zu Matrixeffekten bei der LC-MS/MS-Analytik in Futtermitteln gibt es kaum Daten. Ein Schwerpunkt dieser Arbeit war daher die Untersuchung der Einflussfaktoren auf Matrixeffekte bei der Analyse von Kokzidiostatika. Aufgrund der gewonnenen Erkenntnisse wurde eine Methode zur Bestimmung von Verschleppungen von Kokzidiostatika in Futtermittel für Nichtzieltierarten entwickelt und validiert. Weitere LC-MS/MS-Methoden wurden zur Bestimmung Maduramicins in Futtermittel, Eiweiß und Eigelb optimiert. Diese wurden zur wurden zur Untersuchung des Übergangs des Kokzidiostatikums aus dem Futtermittel in das Ei benötigt. Dazu wurde eine Fütterungsstudie mit Legehennen durchgeführt. Futtermittel mit drei Konzentrationen von Maduramicin bis zum Höchstgehalt in Futtermittel für Nichtzieltierarten wurden hergestellt und je einer Gruppe von Legehennen verabreicht. Das aufgenommene Maduramicin ging ausschließlich ins Eigelb über, es ergab sich eine Carry-over-Rate von 8 %. Der für Eier festgelegte Höchstgehalt von 2 µg/kg wurde überschritten, obwohl die Konzentrationen Maduramicins in den verfütterten Futtermitteln unterhalb des Höchstgehaltes für Futtermittel lagen. Als Folge dieser Ergebnisse wurde der Maduramicin-Höchstgehalt in Ei auf 12 µg/kg angepasst. Der in Verordnung (EG) Nr. 124/2009 festgelegte Höchstgehalt wurde durch die Verordnung (EU) 610/2012 geändert.Prevention of coccidosis by anticoccidial feed additives is of great economic importance in poultry farming. Application of these substances is regulated by European law and is a matter of official feed and food control requiring appropriate determination methods for coccidiostats. In this study, liquid chromatographic tandem mass spectrometric (LC-MS/MS-) methods for the quantification of coccidiostats in feed and eggs were developed. The influence of the sample material resulted in poor method performance. These matrix effects are intensively investigated in other analytical fields like drug or pesticide analysis. In contrast, there are limited data concerning matrix effects in LC-MS/MS analysis in feedingstuffs. This study therefore focussed on the systematic investigation of factors influencing matrix effects during analysis of coccidiostats. The findings were implemented in the development and validation of a method for the determination of cross-contamination levels of authorized coccidiostats in feed for non-target animals. This method was optimized for the determination of the anticoccidial feed additive maduramicin in feed, egg white, and egg yolk for a carry-over study. By means of the conducted feeding trial with laying hens the carry-over of maduramicin from feed into eggs was comprehensively characterized. Three feedingstuffs containing different levels of maduramicin up to the maximum tolerable level in non-target animal feed were prepared and fed to groups of ten laying hens. Maduramicin is exclusively transferred into egg yolk, and a carry-over rate into whole eggs of 8 % was calculated. Although the applied diets were in compliance with the maximum level in feed, resulting concentrations in whole eggs exceeded the maximum level in eggs. As a consequence of these findings, the maximum permitted level of maduramicin in eggs was adapted to 12 µg/kg. The maximum level assigned by Regulation (EC) No. 124/2009 was amended in Regulation (EU) 610/2012.
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Egle, Hannes. "Schnelles und zuverlässiges therapeutisches Drug-Monitoring mit HPLC-UV und LC-LC, MS-MS aus komplexen Matrizes". [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=974035548.
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Silcocks, S. E. "Component analysis of natural products by Lc, Lc-Api-Ms, and Lc-Api-MSN techniques". Thesis, Swansea University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.639034.
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Natural products provide a wide and virtually inexhaustible source of novel, useful, and often hard to synthesise compounds. However, due to the origin of these products, the matrices tend to be complex, and individual components are difficult to isolate and conclusively identify. The majority of this thesis focuses on the separation, identification, and quantification of certain species inherent within natural product samples. Liquid chromatography atmospheric pressure ionisation mass spectrometry techniques were utilised for this research. Chapter One provides a brief history and introduction to the principles and applications of liquid chromatography, mass spectrometry, and their use as an interfaced combined system. Chapter Two incorporates an investigation into the main component groups of cashew nut shell liquid (i.e. cardanol, cardol, 2-methylcardol, and anacardic acid). Compositional trends relative to the degree of applied heat treatment were examined. The compositions of certain regional samples were also compared. Chapter Three encompasses four synthesised phyto-oestrogen compounds known to naturally occur in plant-derived sources suspected as having potential cancer-protective activity. A separation of the four compounds is described, along with an account of their mass spectral identification and characterisation. Selected ion and selected reaction monitoring techniques were utilised for the determination of the limits of detection of each analyte. Chapter Four investigates the highly complex composition of propolis, a natural product manufactured by bees, and reported to provide a range of medicinal benefits. A liquid chromatographic separation of the substance is described. Additionally, differently sourced samples were mass spectrally analysed, and each one characterised and compared by their eight most abundant compounds. Chapter Five is an exception to the majority of the thesis and covers novel double-charge-transfer spectrometry investigations into the double-ionisation energies of acetonitrile and fluorinated benzene molecules. A brief appraisal of theorised values is also included.
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Cao, Xiaoyu. "Mass Exclusion list for RNA modification mapping using LC-MS/MS". University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1495807992024166.
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Li, Huawen. "Quantitative Analysis of Bleomycin in Rat Plasma by LC-MS/MS". Cleveland State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=csu1528851820162444.
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Khedr, Tawfeek. "Bitter sweet: Exploring alkaloid synthesis in lupin using LC-MS/MS". Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2024. https://ro.ecu.edu.au/theses/2811.
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Lupin is a dominant legume crop in Western Australia, with strong domestic and export markets. Due to its high protein and fibre content, coupled with low levels of carbohydrates and fat, lupin has garnered significant interest over other legumes. It is cultivated for a variety of food and animal feed applications. However, lupin products may pose health risks to consumers due to the presence of toxic quinolizidine alkaloids (QAs). Quinolizidine alkaloids serve as natural plant defence mechanisms, and they have wide industrial applications. However, they can be toxic to humans and animals if consumed above the industrial limits (200 mg/kg). The levels of alkaloids in sweet lupin species vary and can occasionally surpass safe consumption thresholds. An accurate and validated methodology for quantifying QAs in lupin seeds is important for monitoring their concentrations across different sweet lupin varieties. Furthermore, the factors contributing to variations in QA levels within lupin seeds demand additional exploration. Currently, most proteins implicated in the biosynthesis and transportation of QAs remain unidentified. This thesis comprises two parts: the first involves establishing a new method for QAs determination in lupin grain and tracking their concentrations across various lupin species and under different daylight durations. The second part explores proteins associated with alkaloid biosynthesis and transportation in lupin through proteomics analysis of lupin leaves, correlating with alkaloid levels.
Chapter 1 of the thesis presents an extensive literature review on the occurrence of QAs in lupin seeds, highlighting the primary gaps in current knowledge. Alkaloids serve a crucial role in defending lupins against insect attacks and enabling plants to adapt to various environmental changes. However, when QAs are present in high concentrations in lupin seeds, they pose toxicity risks to both humans and animals. Since alkaloids are synthesized in lupin leaves and then translocated to the seeds, it is possible to develop a "bittersweet" lupin accession. This accession would contain high levels of alkaloids in the leaves for protection while maintaining low levels in the seeds to ensure safety for consumption. To achieve this goal, there is a need for a precise and accurate method for analysing alkaloids in both lupin seeds and leaves. Additionally, there is a need to develop a proteomics approach to identify key proteins involved in the biosynthesis and transportation of alkaloids.
Chapter 2 of the thesis focuses on the development and validation of an LC-MS/MS method for the quantification of QAs in lupin seeds. This method facilitated the determination of alkaloid levels in seeds from major Lupinus species (Lupinus angustifolius, L. cosentinii, L. albus, L. luteus, and L. mutabilis), obtained from the Australian Grains Genebank. Demonstrating high accuracy and precision, with low limits of detections, the method enabled the identification of trace levels of QAs in individual lupin seeds. Subsequent QAs analysis of narrow-leafed lupin (NLL) accessions is presented in Chapter 3. Seeds from both commercial and wild NLL accessions were cultivated under greenhouse conditions, and their QAs contents were evaluated using the validated LC-MS/MS method. The analysis revealed a broad spectrum of QA levels and profiles among different NLL accessions. For instance, low-alkaloid accessions like Geebung exhibited QA levels below 10 mg/kg, whereas bitter accessions such as GRC5011A reached QA concentrations as high as 100,000 mg/kg. The study also found that the level of biological variation was greater in sweet accessions (CV > 100%) compared to bitter ones (CV < 30%).
In Chapter 4, the thesis explores the intra-plant variability of QA content across three NLL genotypes: Tanjil, Quillinock, and P22660. This analysis extended to assess QA levels in seeds from the same and different plants: within pods, between branches, within individual plant replicates, and across the mentioned accessions. The findings indicated that while variation in QA levels among seeds from the same pods within any given lupin plant was relatively low (CV < 30%) for all studied accessions, variability within a single replicate of a lupin plant could reach as high as 94%. This suggests that intra-plant variation in QA content can, at times, exceed the variation observed between different plant replicates. Additionally, the thesis examines the impact of extended daylight hours, a condition typical within a ‘speed breeding’ greenhouse, on the QA levels in seeds of the Tanjil cultivar. The data suggest that speed breeding growth conditions may influence QA levels in NLL accessions, highlighting a potential area for further research on how controlled environmental conditions can affect alkaloid biosynthesis in lupins.
Chapter 5 introduces a comprehensive multi-omics approach for analysing proteomics and QAs in lupin leaves. This methodology includes the extraction of proteins and alkaloids from the same tissue using a mixture of urea, thiourea, and CHAPS. The method was further validated for alkaloid quantification using LC-MS/MS. By employing the quantitative proteomics SWATH-MS technique and DIA-NN data analysis tool, 4,768 proteins were quantified in leaves of sweet and bitter NLL varieties. Through correlation analysis between protein levels and QA concentrations, the research elucidated connections within the proteome profiles, confirming previously identified proteins involved in QA biosynthesis. From all positively significant modules, we selected the top 351 protein groups, with VIP score > 1, which indicates a strong association between the biosynthesis and transport of QAs. Some proteins were specifically correlated with distinct alkaloid profiles, suggesting their involvement in the biosynthesis of individual alkaloids.
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Brown, Stacy D., e J. Carmichael. "Phospholipid Depletion Techniques in LC-MS Bioanalysis". Digital Commons @ East Tennessee State University, 2019. https://dc.etsu.edu/etsu-works/7850.
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Revised and Expanded Handbook Provides Comprehensive Introduction and Complete Instruction for Sample Preparation in Vital Category of Bioanalysis
Following in the footsteps of the previously published Handbook of LC-MS Bioanalysis, this book is a thorough and timely guide to all important sample preparation techniques used for quantitative Liquid Chromatography–Mass Spectrometry (LC-MS) bioanalysis of small and large molecules. LC-MS bioanalysis is a key element of pharmaceutical research and development, post-approval therapeutic drug monitoring, and many other studies used in human healthcare.
While advances are continually being made in key aspects of LC-MS bioanalysis such as sensitivity and throughput, the value of research/study mentioned above is still heavily dependent on the availability of high-quality data, for which sample preparation plays the critical role. Thus, this text provides researchers in industry, academia, and regulatory agencies with detailed sample preparation techniques and step-by-step protocols on proper extraction of various analyte(s) of interest from biological samples for LC-MS quantification, in accordance with current health authority regulations and industry best practices. The three sections of the book with a total of 26 chapters cover topics that include:
Current basic sample preparation techniques (e.g., protein precipitation, liquid-liquid extraction, solid-phase extraction, salting-out assisted liquid-liquid extraction, ultracentrifugation and ultrafiltration, microsampling, sample extraction via electromembranes) Sample preparation techniques for uncommon biological matrices (e.g., tissues, hair, skin, nails, bones, mononuclear cells, cerebrospinal fluid, aqueous humor) Crucial aspects of LC-MS bioanalytical method development (e.g., pre-analytical considerations, derivation strategies, stability, non-specific binding) in addition to sample preparation techniques for challenging molecules (e.g., lipids, peptides, proteins, oligonucleotides, antibody-drug conjugates) Sample Preparation in LC-MS Bioanalysis will prove a practical and highly valuable addition to the reference shelves of scientists and related professionals in a variety of fields, including pharmaceutical and biomedical research, mass spectrometry, and analytical chemistry, as well as practitioners in clinical pharmacology, toxicology, and therapeutic drug monitoring.
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Bui, Thinh Quang. "ANALYSIS OFMERCURY THIOL COMPLEXESBY LC ICP-MS". Thesis, Umeå universitet, Kemiska institutionen, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-163383.
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Měřínská, Radana. "Analýza flavonoidů v pivu metodou LC-MS". Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2010. http://www.nusl.cz/ntk/nusl-216608.
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Presented diploma thesis is focused on analysis of phenolic compounds in various types of beers. The aim of this work was to find possible differences among several types of beers and also between Czech beers and beers of foreign production. Theoretical part contains detailed description of beer technology, review of important analytical methods for determination of phenolic compounds and total antioxidant activity. The main attention is focused on instrumental technique LC/MS. In the experimental part values of total phenolics and total flavonoids and results of antioxidant status in analyzed beers were determined spectrophotometrically. Basic brewing characteristics were determined by pycnometry. On-line liquid chromatography with photo diode array detection and mass spectrometry detection was used for identification and quantification of individual phenolic compounds. Spectrophotometric analysis of phenolic and flavonoid levels seems to be less specific, that is consistent with findings in accessible literature. It was proved, that iso- bitter compounds exhibit about 65.44 – 90.93 % of the total bitter substances. These components are responsible for the main part of beer bitterness. The HPLC/PDA/ESI-MS was necessary to use for determination of characteristic phenolic compounds in individual types of beer. Within our measurement three columns were tested, the most favourable results were obtained using the column Restek C18. When compared with foreing beers, in Czech beers higher level of majority of phenolic compounds was detected and specific distribution of individual derivatives was found as well.
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Amparo, Maura Roquete. "Desenvolvimento e validação de métodos SPE-LC-MS e MEPS-LC-MS para quantificação de fluoroquinolonas em matrizes aquosas". Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/75/75135/tde-30072013-091333/.
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Os antimicrobianos, especialmente a classe das fluoroquinolonas (FQs), são utilizados em grandes quantidades na medicina humana e veterinária. Uma atenção especial deve ser dada à ocorrência desses fármacos em diferentes matrizes ambientais, devido a potencialidade de propagação da resistência bacteriana. As principais fontes dessa contaminação são os esgoto industrial, urbanos, esgoto sanitário de hospital e de fazendas que utilizam antibióticos com finalidades veterinárias. Após a ingestão, os antimicrobianos são excretados na sua forma inalterada e, devido a baixa eficiência dos sistemas convencionais de tratamento de esgoto, são eventualmente liberados para o meio aquático. Diferentes métodos têm sido desenvolvidos para a determinação de FQs em amostras aquosas diversas, tais como esgoto sanitário , água de abastecimento, águas superficiais e esgoto sanitário de hospital. A maior parte dessas amostras ambientais é complexa e exige uma série de etapas de preparo, limpeza e pré-concentração; de maneira que, nos últimos anos, extensos esforços têm sido feitos para o desenvolvimento de novas técnicas de preparo de amostra que reduzam o tempo, trabalho, consumo de solvente e que permitam melhor desempenho do processo analítico. Nesse estudo foram desenvolvidos dois métodos de extração - a extração em fase sólida (SPE ) e a microextração por sorvente empacotado (MEPS) - sendo a separação, identificação e quantificação feitos por HPLC-MS/MS. Os métodos foram avaliados e validados segundo os parâmetros: precisão, exatidão, recuperação, linearidade, limite de detecção (LD), limite de quantificação (LQ), seletividade, efeito matriz, eficiência total do processo e robustez. Posteriormente, foi feita aplicação dos métodos desenvolvidos para investigação de FQs em águas superficiais e amostra de esgoto coletadas em diferentes pontos da cidade de São Carlos-SP. Os métodos apresentaram valores de recuperação maiores que 80% para as FQs estudadas, e valores de exatidão e precisão menores que 30% . A comparação entre as técnicas de extração desenvolvidas permitiu listar vantagens e desvantagens particulares de cada técnica. Além do menor consumo de solventes e volume de amostras, valores insignificantes de efeito matriz foram alcançados para a técnica MEPS; no entanto a SPE, devido ao seu maior fator de concentração, permitiu a quantificação de duas fluoroquinolonas em amostra de esgoto doméstico e detecção das mesmas em amostra de rio.Antimicrobials, particularly the fluoroquinolones (FQs) class, are widely used in human and veterinary medicine. Particular attention must be given to the occurrence of these drugs in different environmental matrices, due to the potential spread of bacterial resistance. Effluents from industries, residential districts, hospitals and animal farms are the main sources of contamination by antibiotics. After ingestion, the antimicrobials are excreted in its unchanged form. Due to the low efficiency of conventional wastewater treatments, these antimicrobials are eventually released into the aquatic environment. Several methods have been developed for the determination of FQs in different water samples, such as municipal wastewater, tap water, river water, and hospital sewage. Most of these environmental samples is complex and requires a number of preparation steps, cleaning and preconcentration. For this reason, recently, extensive efforts have been made to develop new techniques for sample preparation in order to reduce: time, number of steps, solvent consumption and achieve better performance on the analytical process. This work describes the development of two methods of extraction - by solid phase extraction (SPE) and microextraction by packed sorbent (MEPS) - and separation, identification and quantification by HPLC-MS/MS. These methods were evaluated and validated by studying the following parameters: accuracy, precision, recovery, linearity, limit of detection (MDL), limit of quantification (MQL), selectivity, matrix effect, process efficiency and robustness. These methods were subsequently applied for FQs investigation in surface water and sewage sample collected at different points in the city of Sao Carlos/SP, Brazil. The methods recoveries achieved values greater than 80% for the studied FQS and the accuracy and precision values were satisfactory when compared to the values acceptable by regulatory agencies such as EPA and AOAC. A comparison between the extraction techniques developed allowed listing advantages and disadvantages of each particular technique. Besides the lowest solvent consumption and volume of samples, negligible values of matrix effects were achieved for MEPS technique. However, SPE, due to its higher pre-concentration, allowed the quantification of two fluoroquinolones in a sample of sewage and the detection in river sample.
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GIACCONE, VITA. "Identificazione e quantificazione delle Micotossine prodotte da Alternaria in alimenti e mangimi, mediante LC-MS/MS e LC/HRMS". Doctoral thesis, Università degli studi di Modena e Reggio Emilia, 2022. http://hdl.handle.net/11380/1276559.
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Le micotossine sono contaminanti significativi negli alimenti e nei mangimi e sono causa di gravi effetti tossici sulla salute umana e animale. Diversi studi hanno dimostrato l’esistenza di una moltitudine di metaboliti fungini che contaminano alimenti e mangimi. Recentemente, le autorità sanitarie internazionali hanno espresso preoccupazione per la presenza di micotossine "emergenti" negli alimenti. Tra le specie fungine responsabili della produzione di tali metaboliti, la specie Alternaria ha la capacità di produrre più di 70 tossine, come Alternariol (AOH), Alternariol monomethyl ether (AME), Tenuazonic Acid (TeA) e Tentoxin (TEN), presenti nei cereali, in prodotti a base di pomodoro, nell’olio d'oliva, nella frutta e nella verdura fresca. Queste micotossine sono state recentemente oggetto di pareri scientifici dell'Autorità Europea per la Sicurezza Alimentare (EFSA), che ha espresso preoccupazione per la scarsa disponibilità di dati sull'incidenza negli alimenti destinati al consumo umano e animale. Esiste, infatti, un alto grado di incertezza legato alla rappresentatività degli alimenti attualmente testati. Inoltre, la mancanza di informazioni sul metodo analitico utilizzato contribuisce ulteriormente a creare incertezza sui livelli di tossine da Alternaria. Sono necessari ulteriori studi per aggiornare la valutazione del rischio da parte dell'EFSA e, pertanto, l'obiettivo specifico di questo progetto era incentrato sullo sviluppo di metodi LC-MS/MS e LC/HRMS accurati per l'analisi delle tossine da Alternaria. Il progetto è stato sviluppato in collaborazione con l'Istituto Zooprofilattico Sperimentale della Sicilia. Il metodo LC-MS/MS è stato utilizzato per l'analisi target delle micotossine emergenti nelle matrici alimentari. In particolare sono state svolte le seguenti attività:
• ottimizzazione dei parametri del metodo per lo screening simultaneo di Alternariol (AOH), Alternariol monometiletere (AME), Acido tenuazonico (TeA), Ocratossine e Zearalenone (ZEA), Fumonisina B1, B2, B3, tossina T-2, HT-2 tossina e deossinivalenolo (DON) (vomitossina);
• sviluppo di un protocollo di preparazione del campione, da applicare a cereali e frutta secca; il protocollo di preparazione del campione si è basato su una doppia estrazione (estrazione liquida) e purificazione mediante estrazione in fase solida (SPE).
• validazione del metodo secondo le linee guida comunitarie (Decisione della Commissione 2002/657/CE); il metodo è stato ottimizzatoo valutando i seguenti parametri: specificità, precisione, linearità strumentale, recupero, limite di decisione (CCα), capacità di rilevamento (CCβ), effetto matrice e robustezza.
La cromatografia accoppiata alla spettrometria di massa ad alta risoluzione (UHPLC-Q-HRMS) è stata utilizzata per la determinazione, sensibile e specifica, delle tossine da Alternaria. Le prestazioni ottenute sono state confrontate con quelle ottenute mediante cromatografia liquida ad alte prestazioni. Tutti e due i metodi hanno mostrato una buona linearità e ripetibilità. Si dice che lo spettrometro di massa Q-Exactive sia più adatto per il rilevamento in tracce rispetto ai metodi MS/MS basati sul triplo quadrupolo, perché, nonostante abbia prestazioni comparabili, ha una migliore selettività.
Il progetto di ricerca avrebbe dovuto fornire un'ampia indagine sul contenuto emergente di micotossine in vari prodotti alimentari, contribuendo a una stima dell'esposizione al rischio di micotossine. Le difficoltà legate alla pandemia in corso hanno reso difficile la ricerca, inizialmente prevista in questo progetto. Nonostante tutto, lo scopo di questo lavoro è stato colmare il vuoto di dati e fornire informazioni rilevanti per migliorare la sicurezza dei prodotti locali.Mycotoxins are significant contaminants in food and feeds. These molecules have demonstrated serious effects in both human and animal health. Different studies showed the presence of a multitude of fungal metabolites that contaminate food and feed. Recently, the international health authorities have expressed concerns about the presence of "emerging" mycotoxins in foodstuffs. The term “emerging mycotoxins” is commonly referred to those compounds that are currently under the spotlight of the scientific community and the policy-makers, due to their toxicological profile. Among the fungal species responsible for the metabolite production, Alternaria species have the ability to produce more than 70 toxins, such as Alternariol (AOH), Alternariol monomethyl ether (AME), Tenuazonic Acid (TeA) e Tentoxin (TEN), found in cereals, tomato products, olive oil, fresh fruits and vegetables. These mycotoxins have been recently covered by scientific opinions from the European Food Safety Authority (EFSA), who has expressed concern about the low availability of incidence data in food for human and animal consumption. There is, indeed, a high degree of uncertainty related to the representativeness of the food currently tested because it contains too many inaccuracies. Furthermore, the lack of information on the analytical method used further contributes to the uncertainty of the reported Alternaria toxin levels. More comprehensive studies are required to update the risk evaluation by the EFSA and, therefore, the specific aim of this project was focussed on the development of accurate LC-MS/MS and LC/HRMS methods for the analysis of emerging Alternaria toxins. The protocol was employed in collaboration with the Istituto Zooprofilattico Sperimentale della Sicilia. LC-MS/MS method was used for the target analysis of emerging mycotoxins in food matrices. In particular, the following activities were carried out: • optimisation of the method parameters for simultaneous screening of Alternariol (AOH), Alternariol monomethyl ether (AME), Tenuazonic Acid (TeA), Ochratoxins and Zearalenone (ZEA), Fumonisin B1, B2, B3, T-2 toxin, HT-2 toxin and deoxynivalenol (DON) (vomitoxin); • development of a sample preparation protocol, apply to cereals and dry fruits; the sample preparation protocol was based on a double extraction (Liquid extraction) and purification through solid-phase extraction (SPE). • validation of the method according to EU guidelines (Commission Decision 2002/657/EC); the method was performed by evaluating the following parameters: specificity, precision, instrumental linearity, recovery, decision limit (CCα), detection capability (CCβ), matrix effect and ruggedness. The ultrahigh-performance chromatography coupled to quadrupole-orbitrap high-resolution mass spectrometry (UHPLC-Q-HRMS) was applied to the sensitive and specific determination of the emerging Alternaria toxins. Performances were compared to those obtained by high-performance liquid chromatography detection. All two methods showed good linearity and repeatability. The Q-Exactive mass spectrometer is said to be better suitable for trace detection than state-of-the-art MS/MS methods based on the triple quadrupole, because, despite having performance comparable, it has better selectivity. The research project should have provided a broad investigation of the emerging mycotoxin content in various food products, contributing to an estimate of mycotoxin risk exposure. The difficulties linked to the pandemic in progress made difficult research, initially planned within this project. Despite everything, the purpose of this work was to fill the data gap and provide relevant information to improve the safety of local products.
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Junza, Martínez Alexandra. "Desarrollo de métodos de determinación e identificación de antibióticos y sus metabolitos en alimentos de origen animal por LC-MS y LC-MS/MS". Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/308127.
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Los antibióticos se usan en medicina veterinaria para curar enfermedades, para prevenirlas (uso profiláctico) y como promotores del crecimiento, aunque este último uso está prohibido en la Unión Europea desde 2006. La presencia de residuos de antibióticos en muestras alimentarias de origen animal supone un riesgo para la salud de los consumidores. Estos residuos pueden provocar problemas de alergias y toxicidad en individuos sensibles y generar resistencia bacteriana. Con el fin de proteger la seguridad alimentaria del consumidor, la UE estableció en la Regulación 2377/90/EC, unos límites máximos de residuos (MRL), es decir, concentraciones máximas de fármaco que pueden estar presentes en los alimentos de origen animal, para que sean seguros para el consumo humano. Durante esta tesis doctoral se han desarrollado y validado cuatro métodos multiresiduo para la determinación de quinolonas y β-lactamas (penicilinas y cefalosporinas) en leche de vaca siguiendo la normativa Europea 657/2002 y la guía de la FDA. Los métodos optimizados se basan en distintos tratamientos de muestra (extracción en fase sólida (SPE), microextracción líquido líquido dispersiva (DLLME) y extracción asistida por ultrasonidos seguida de una extracción en fase sólida dispersiva (USE-d-SPE)) y se analizaron por cromatografía de líquidos acoplada a la espectrometría de masas en tándem (LC-MS/MS).
Con el fin de que la leche pueda ser apta para el consumo humano, es necesario que pase un determinado tiempo entre la última administración del antibiótico al animal y la recogida de la leche, con el fin de que pueda eliminarse del organismo los antibióticos y sus metabolitos. Si no se respeta este tiempo, la leche procedente de vacas medicadas con antibióticos puede contener residuos de éstos, además de compuestos resultantes de la metabolización en el animal. Por otro lado, también requiere que se eliminen los microorganismos patógenos a través de la aplicación de determinados tratamientos térmicos. Es de especial interés el estudio de la metabolización de los antibióticos y como pueden afectar los tratamientos térmicos sobre éstos, dando lugar a productos de transformación (TPs). Al igual que los antibióticos administrados, tanto los metabolitos como los TPs pueden provocar efectos adversos como toxicidad, alergias y en el caso de mantener la actividad antibacteriana, resistencia bacteriana. Así, en el segundo bloque de esta tesis, se ha estudiado la metabolización de diferentes antibióticos (ENR, CIP, DIF, SAR, AMOX, PENG, PIR y TIO), y la influencia de los tratamientos térmicos en la estructura de los antibióticos. Para conseguir este objetivo se han analizado diferentes muestras de leche fortificadas con quinolonas y β-lactamas, y también se han estudiado muestras de leche procedentes de animales medicados con enrofloxacina (ENR) y benzilpenicilina (PENG) y recogidas durante los tres días de tratamiento farmacológico y durante los cuatro días posteriores a la finalización de éste. Las muestras se analizaron mediante LC-ToF y LC-LTQ-Orbitrap. Se han determinado y caracterizado más de 60 TPs y metabolitos, siendo más de la mitad descritos por primera vez.The presence of antibiotic residues in food samples from animal origin is a risk to consumer health. These residues can cause allergies and toxicity problems in sensitive individuals and create bacterial resistance. In order to protect food consumer safety, the EU established in Regulation 2377/90/EC, a maximum residue levels (MRL). During this PhD thesis four multi-residue methods for the determination of quinolones and β-lactams (penicillins and cephalosporins) in cow's milk according to the European regulation 657/2002 and FDA guidance have been developed and validated. Optimized methods are based on various sample treatments (solid phase extraction (SPE), liquid dispersive liquid microextraction (DLLME) and ultrasound assisted extraction followed by a dispersive solid phase extraction (USE-d-SPE)) and analyzed by liquid chromatography coupled to tandem mass spectrometry (LC-MS / MS). If a cow medicated is milked too soon, before all antibiotic and its metabolites are eliminated from the body, residues of the administered antibiotic and their metabolites can be found in the milk. These can pass to humans through the food chain causing health problems such as allergies, toxicity and resistant bacterial strains. On the other hand, milk is treated thermally (pasteurisation and sterilization) before human consumption to eliminate pathogens microorganisms. These processes can affect the residues of antibiotics and their metabolites modifying their structures and given several transformation products (TPs). Thus, in the second part of this thesis, we have studied the metabolism of different antibiotics (ENR, CIP, DIF, SAR, AMOX, PENG, PIR and TIO) and the influence of heat treatment on the structure of antibiotics. To achieve this goal different samples of milk fortified with quinolones and β-lactams have been analyzed. Samples of milk from animals medicated with enrofloxacin (ENR) and benzylpenicillin (PENG) and collected during the three-day of pharmacologic treatment and during the four days following the end of it have also studied. Samples were analyzed by LC-ToF and LC-LTQ-Orbitrap. They have been identified and 60 characterized TPs and metabolites, over half first described
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Becker, Matthias. "LC-MS/MS-Methoden zur Rückstandsanalyse von Penicillinen, Cephalosporinen und Aminoglycosid-Antibiotika". [S.l. : s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=974085324.
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Zerck, Alexandra [Verfasser]. "Optimal precursor ion selection for LC-MS/MS based proteomics / Alexandra Zerck". Berlin : Freie Universität Berlin, 2014. http://d-nb.info/1047579065/34.
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Malone, Edward Martin. "The determination of veterinary residues in edible matrices using LC-MS/MS". Thesis, Queen's University Belfast, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.534621.
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Utami, Wahyu. "Ion pairing LC-MS/MS method for analysis of intracellular phosphorylated metabolites". Thesis, University of Nottingham, 2015. http://eprints.nottingham.ac.uk/30566/.
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Nucleoside analogues have been extensively used in medication. The nucleoside analogue cordycepin is the principal bioactive compound found in the caterpillar fungi (Cordyceps and Ophiocordyceps). It has been shown to have biological activity, including anti-inflammatory, immunomodulatory and anti-proliferative activity in many kinds of malignant cells. Intracellular drug interactions at the nucleotide level can be explained by understanding the intracellular metabolism of nucleoside analogues as well as their plasma metabolism since their efficacy of therapy or toxicity does not associate with the plasma level of nucleoside. Therefore, investigation of the metabolism of nucleoside analogues is required for a full understanding of their pharmacological activity and toxicity. For that reason, here an ion pairing LC-MS/MS method has been developed for quantitative analysis of the nucleoside analogue cordycepin and the metabolites and its application to cell culture, using in vitro and in vivo studies. Several HPLC parameters and extraction techniques have been optimised, followed by optimisation of the mass spectrometry method by examining the fragmentation of nucleotides. The method was then validated and applied to study the metabolism of cordycepin in vitro and in vivo, to investigate the effect of the cordycepin treatment with or without pentostatin on the intracellular level of endogenous nucleotides, and to examine the intracellular metabolism of nucleoside analogue 4-thiouridine and the effect of its metabolite on the metabolic balance of adenine and uridine nucleotides. The study on the intracellular metabolism of cordycepin in MCF7 and HeLa cells shows that cordycepin was rapidly metabolized into the deaminated form by adenosine deaminase (ADA) in culture medium as well as in cancer cells; therefore combination with pentostatin, an ADA inhibitor, resulting in the highly accumulated phosphorylated metabolite intracellularly. In contrast, cordycepin in C. militaris extracts showed much lower degradation in non-heat-treated serum compared with pure cordycepin that indicates a strong evidence of the presence of a deaminase inhibitor in the extract of Cordyceps. Moreover, the determination of concentrations of cordycepin and the metabolites in the plasma and liver of rats dosed with cordycepin proves that the half-life of cordycepin and its metabolites are very short in the plasma; nevertheless they are accumulated in the liver with repeated administration. Treatment using cordycepin initially caused an increase in the intracellular concentrations of nucleoside triphosphate, but in the long term, the active metabolite of cordycepin likely induced a long term change in the cell resulting in a drop in nucleotide levels. Pentostatin on its own reduced nucleoside triphosphates levels in the long term and combination with cordycepin increased the effect of cordycepin on nucleotide concentrations. High levels of the accumulated cordycepin triphosphate led to a massive decline in nucleotide levels. A study on the intracellular metabolism of nucleoside analogue 4-thiouridine has shown that generally the uptake of 4-thiouridine into NIH 3T3 cells was fast and the phosphorylated metabolite rapidly was developed only after two min labelling. However, it was also shown that its phosphorylation was not very efficient, but the level of the phosphorylated metabolite increased in serum-stimulated cells likely because the enzyme was upregulated in the presence of growth factor. Moreover, the present study provides additional evidence that 4-thiouridine and its metabolite have no adverse effect on the metabolic balance of adenine and uridine nucleotides. This study confirms that pharmacological activity of nucleosides analogues and their cytotoxicity highly rely on the accumulation of their phosphorylated metabolites. Consequently, the activity and the level of the enzymes involved in their metabolism are highly influential on their pharmacological action as well as their toxicity.
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Pereira, Mararlene Ulberg. "Determinação de resíduos de ionóforos poliéteres em leite por LC-MS/MS". reponame:Repositório Institucional da FIOCRUZ, 2013. https://www.arca.fiocruz.br/handle/icict/7864.
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Fundação Oswaldo Cruz. Instituto Nacional de Controle de Qualidade em Saúde
Os ionóforos poliéteres são antibióticos utilizados em bovinos como promotores de crescimento, para aumentar a produção de leite em vacas lactentes e prevenir e tratar a coccidiose. Entretanto, poucos são os métodos para determinação destes resíduos em leite e não há dados de monitoramento disponíveis no Brasil. Este trabalho teve como objetivo desenvolver, validar e aplicar um método para a determinação de resíduos de seis antibióticos da classe dos ionóforos poliéteres (lasalocida, maduramicina, monensina, narasina, salinomicina e senduramicina) em leite cru, UHT, pasteurizado e em pó empregando a extração QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) e a cromatografia líquida de alta eficiência acoplada à espectrometria de massas sequencial (LC-MS/MS). Recuperações globais de 92,8 a 112,7% e desvios padrão relativos inferiores a 16% foram obtidos em condições de precisão intermediária. Os valores de CCα calculados não ultrapassaram 20% do Limite Máximo de Resíduo (LMR) para a monensina e 25% dos Níveis Máximos (NM) para as demais substâncias. Os limites de detecção estimados variaram de 0,03 µg/L a 0,4 µg/L e os limites de quantificação de 0,07 µg/L a 0,9 µg/L para a salinomicina e maduramicina, respectivamente. Estes resultados demonstraram que o método desenvolvido e validado é adequado para a determinação de resíduos de lasalocida, maduramicina, monensina, narasina, salinomicina e senduramicina em leites em pó, cru, UHT e pasteurizado, para fins de verificação da conformidade de amostras em relação aos limites recomendados pelo Codex Alimentarius e pela Comunidade Europeia. O método foi aplicado em 102 amostras de leite integral UHT comercializadas na região metropolitana do Rio de Janeiro, fornecendo dados inéditos no Brasil sobre a ocorrência de resíduos de ionóforos poliéteres neste produto de origem animal. A substância monensina foi detectada em 13,7% das amostras, mas nenhuma apresentou resultados acima dos limites regulatórios. O método validado poderá ser utilizado no INCQS para análises de rotina, contribuindo para ações de vigilância sanitária.
Polyether ionophores are antibiotics used in cattle to promote growth, enhance milk production in dairy cows and prevent and treat coccidiosis. However, there are just a few methods for determining these residues in milk and no monitoring data available in Brazil. This study aimed to develop, validate and apply a method for determining residues of six antibiotics belonging to the polyether ionophore class (lasalocid maduramicin, monensin, narasin, salinomycin and semduramicin) in raw, UHT, pasteurized and powdered milk using QuEChERS extraction (Quick, Easy, Cheap, Effective, Rugged, Safe) and high performance liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Overall recoveries from 92.8 to 112.7% and relative standard deviation lower than 16% were obtained in intermediate precision conditions. CCα calculated values did not exceed 20% the Maximum Residue Limit (MRL) for monensin and 25% the Maximum Levels (ML) for the remaining substances. Estimated detection limits ranged from 0.03 µg/L to 0.4 µg/L and limits of quantification from 0.07 µg/L to 0.9 µg/L for salinomycin and maduramicin, respectively. These results showed that the developed and validated method is suitable for the determination of residues of lasalocid, maduramicin, monensin, narasin, salinomycin and semduramicin in powder, raw, pasteurized and UHT milk, for sample compliance evaluation regarding the limits recommended by Codex Alimentarius and European Community. The method was applied for 102 samples of UHT whole milk marketed in the metropolitan region of Rio de Janeiro, Brazil, providing unpublished data on the occurrence of polyether ionophores residues in this animal product. The substance monensin was detected in 13.7% of samples, but none of them showed results above the regulatory limits. The validated method could be used in INCQS for routine analysis, contributing to health surveillance actions.
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Guldberg, Trude Sophie Kristensen. "Deteksjon og kvantifisering av lipofile algetoksiner i skjell ved LC-MS/LC-MSMS". Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-25267.
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Mikroskopiske plantealger kan danne marine algetoksiner i svært lave konsentrasjoner, og disse algetoksinene kan under gitte forhold akkumulere i skjell. I næringsmiddelsammenheng kan inntak av giftige skjell føre til alvorlige forgiftninger eller død.Det finnes fire ulike grupper av marine algetoksiner: diarégivende, paralyserende, nevrotoksiske og det såkalte hukommelsestaptoksinet. De fettløselige algetoksinene – okadasyre, dinophysistoksiner, azaspiracid toksiner, pectenotoksiner, yessotoksiner, spirolider og gymnodiminer – danner en gruppe komponenter som kalles lipofile algetoksiner. I henhold til regelverkskravet fra myndighetene for å sikre folkehelsen, skal forekomster og konsentrasjoner av lipofile algetoksiner i skjell overvåkes. Inntil nylig har biologisk testing i mus vært referansemetoden innen EU for påvisning av toksiske nivåer av lipofile algetoksiner i skjellmat. Dette er nå endret slik at det skal benyttes kjemiske analysemetoder hvor væskekromatografi kombineres med tandem-massespektrometri (LC-MSMS).Målet med denne oppgaven var å gjøre en vurdering av LC-MSMS-metodene som er foreslått i EU-Harmonised Standard Operating Procedure for determination of Lipophilic marine biotoxins in molluscs by LC-MSMS (EU-SOP). To av metodene som beskrives i EU-SOP (sur og basisk metode) ble sammenlignet med pH-nøytral metode (LC-MS). Den sistnevnte er siden 2007 blitt benyttet rutinemessig ved Avdeling for Klinisk Farmakologi, St Olavs Hospital.For de fleste toksinene var alle kvalitetskriterier ved de tre undersøkte elueringsbetingelsene i samsvar med hva EU-SOP anser som akseptabelt ved kvantitativ analyse. Det ble påvist forskjeller mellom metodene, både når det gjaldt kromatografisk toppfasong, linearitet og endringer i instrumentfølsomhet i løpet av analyseserien, så vel som signal-til-støy forhold. Kromatografiske betingelser hadde relativt stor effekt på følsomhet og matrikseffekt. pH nøytral metode viste generelt minst matrikseffekt, selv om matriksstyrken var høyest i ekstraktene som ble analysert på LC-MS. Både sur og basisk metode krever tiltak for å håndtere matrikseffekt for de fleste toksinene og dermed redusere kvantifiseringsfeil.Denne studien viste at matrikseffekt kan være artsavhengig, og at graden av matrikseffekt kan variere med årstid. Variasjon i matrikspåvirkning innen kamskjell relatert til de undersøkte årstidene, var større enn variasjonen innen blåskjell. Resultatene tyder på at valg av kamskjell som blankmateriale for standardkurve bør følge inneværende sesong. Det ble utført sammenligning av toksinkonsentrasjon i naturlig kontaminerte skjell ved standardaddisjon og kvantifisering ved bruk av matriksmatchende standardkurve. Resultatene viste at matriksmatchende standarder i stor grad eliminerte matrikseffekten. I tillegg antydet resultatene at toksinestimering i blåskjell og kamskjell kan gjøres ved å bruke samme kalibreringsmatriks, selv om egen matriks som kalibreringsmatriks ga noe bedre resultater for nøyaktighet og presisjon. Undersøkelse i forbindelse med innføring av potensielle internstandarder viste utfordringer i forhold til å finne egnede forbindelser som er i stand til å kompensere for responsvariasjon og matrikseffekt ved analyse av lipofile algetoksiner. Lovende resultater ble indikert for enkelte toksiner, men ytterligere undersøkelser er nødvendig for å kunne konkludere.Alle tre metodene er egnet for bestemmelse av marine algetoksiner. Imidlertid må matrikseffekt vurderes nøye og tas i betraktning før kvantifisering av toksininnhold. Total analysetid ble betydelig redusert ved bruk av LC-MSMS-metodene. Muligheten ved bruk av dynamisk MRM som sørger for rask polaritetsbytte, fjerner kravet til full baselinjeseparasjon i tillegg til å gi høy sensitivitet ved analyse av komplekse prøver som inneholder mange analytter i lav konsentrasjon i ulike matrikser. Likevel må enkelte kompromisser ofte gjøres i analytiske metoder som inkluderer mange forbindelser, og valget av en rutinemetode for toksinovervåking bør gjøres med vekt på forventet toksinprofil i skjellene.
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Miranda, e. Silva Lígia Maria 1982. "Validação de método de análise de multiresíduos de defensivos agrícolas por GC-MS/MS e LC-MS/MS". [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/254815.
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Orientador: Marcelo Alexandre PradoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos
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Resumo: O crescente aumento populacional em escala mundial, tornou necessário um grande esforço por parte da agricultura para aumentar, a cada ano, a produção de alimentos para atender as necessidades do mercado externo e interno do Brasil. Recursos técnicos e científicos passaram então, a serem aplicados em busca da melhoria na produção dos cultivos,principalmente mediante o uso de fertilizantes e praguicidas. Com isso, a sociedade se deparou com problemas de ordem de equilíbrio ambiental e saúde pública, pois devido à contínua diversificação dos fitoparasitas, surgem, a todo momento, reduções do período de tempo entre aplicações consecutivas, e mais importante talvez, usos de doses mais altas e emprego simultâneo de diferentes pesticidas, por parte dos agricultores, objetivando complementar ações específicas ou alcançar efeitos sinérgicos para maiores rendimentos na produção. Tal situação traz como conseqüência óbvia e direta, o aumento, inaceitável, dos riscos de contaminação do meio ambiente com resíduos químicos de defensívos da área agropecuarista prejudiciais à saúde, o que leva a inúmeros problemas relativos à segurança alimentar dos produtos consumidos, e à uma preocupação de âmbito nacional evidenciada pela criação do Programa de Análise de Resíduos de Agrotóxicos em alimentos (PARA) da ANVISA. O aumento na necessidade de detecção e quantificação destes compostos, acarretou o desenvolvimento de pesquisas no setor, a fim de atingir uma melhoria na eficiência,qualidade e rapidez de resposta nas análises. A possibilidade do estudo de não apenas um de cada vez, mas de até 300 compostos sendo extraídos, detectados e quantificados simultâneamente se tornou a saída mais viável, tanto qualitativa quanto economicamente, facilitando o monitoramento contínuo do fornecimento de produtos do setor alimentício pelos chamados métodos multiresíduos. O presentre trabalho teve como princípio a validação de um método multiresíduo para análise de 14 analitos usando uma técnica de alto poder de concentração e limpeza do extrato como o GPC (Gel Permeation Chromatography) e detecção e quantificação por GC-MS/MS e LC-MS/MS. Os pesticidas investigados englobam classes como: acaricidas, inseticidas, fungicidas, nematicidas e formicidas de aplicação foliar, em sementes ou em solo, sendo que o acefato, metamidofós, acetamiprido e o thiamethoxan foram extraídos de amostras de batata e feijão e analisados por LC-MS/MS e a azoxistrobina, bifentrina, carbofuran, chlorotalonil, clorpirifós, clorfenapir, etofenprox, famoxadone,metalaxil, procimidone e o tebuconazole em amostras de batata e tomate e analisados por GCMS/MS. Os limites de detecção (LD) encontrados variaram de 0,06 a 2,89µg/L, e os coeficientes de variação (CV), de 0,036 a 2,036%. As recuperações foram determinadas em cada tipo de amostras, e os valores encontrados estavam entre 93,34% e 109,67%. Nenhuma das matrizes utilizadas apresentaram resultados insatisfatórios e o método utilizado mostrouse robusto e de fácil aplicação para todos os analitos testados
Abstract: The growing population worldwide, has required a great effort on the part of agriculture to increase each year, the production of food to meet the needs of external and internal market of Brazil. Technical and scientific resources spent then, to be applied in pursuit of improved crop production, mainly through the use of fertilizers and pesticides.With this, the company encountered problems in the balance of environmental and public health, since due to the continuous diversification of plant parasites, arise at any moment,reductions in the time period between consecutive applications, and perhaps most important,uses more doses high and simultaneous use of different pesticides by farmers, aiming to complete specific actions or to achieve synergistic effects in producing higher yields. This situation brings obvious and direct consequence, the increase unacceptable risk of environmental contamination with chemical residues from pesticides in farms are harmful to health, which leads to numerous problems relating to food safety of the products consumed, and to a concern nationwide evidenced by the creation of the Program Analysis of Pesticide Residues in Food (TO) of ANVISA. The increase in the necessity for detection and quantification of these compounds, led the development of research in the sector in order to achieve an improvement in efficiency, quality and responsiveness in the analyzes. The possibility of studying not just one at a time, but up to 300 compounds being extracted,detected and quantified simultaneously output became more viable, both qualitatively and economically, facilitating continuous monitoring of the supply of products by the food industry called methods multiresidue. The principle presentre work was the validation of a multiresidue method for analysis of 14 analytes using a technique of high power concentration and cleanup of the extract as GPC (Gel Permeation Chromatography) and detection and quantification by GC-MS/MS and LC- MS / MS. The pesticides investigated include classes such as acaricides, insecticides, fungicides, insecticides and nematicides foliar, seed or soil,and acephate, methamidophos, and Acetamiprid thiamethoxan were extracted from samples of potatoes and beans and analyzed by LC-MS / MS and azoxystrobin, bifenthrin, carbofuran,chlorothalonil, chlorpyrifos, chlorfenapyr, etofenprox, famoxadone, metalaxyl, procymidone and tebuconazole in samples of potato and tomato and analyzed by GC-MS/MS. The limits of detection (LOD) ranged from 0.06 to 2.89 mg / L, and the coefficients of variation (CV), 0.036 to 2.036%. The recoveries were determined for each type of samples, and the values were between 93.34% and 109.67%. None of the arrays used had unsatisfactory results and method proved to be robust and easy to apply for all analytes tested
Mestrado
Ciência de Alimentos
Mestra em Ciência de Alimentos
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Kirk, John Daniel. "Particle beam LC/MS with fast atom bombardment". Thesis, Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/27127.
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Alsuidan, Abdulelah. "Identification of ink degradation products by LC-MS". Thesis, Loughborough University, 2009. https://dspace.lboro.ac.uk/2134/34532.
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The aging processes of ink dyes in ballpoint inks were determined using modem chromatographic and spectrometric methods with their possible application. Two main methods were applied IP–HPLC method with photodiode array detection for ink dyes separation and LC–MS method for the identification of ink degradation products as a function of age, for this purpose the two methods were developed and validated. The aging processes of standard dyes as reference substances at different conditions (light and heat) were investigated. These processes were used then on ink entries on paper. Dye components and their degradation products were successfully separated and identified by their retention time, UV-visible absorption profiles and mass spectra. Different blue ballpoint inks were identified and discriminated by comparing their relative peaks areas (RPA) to obtain the aging profiles. Moreover, other types of ink (gel pens, fibre tips and different colours) were also analysed and discriminated successfully by the developed method. In addition, several months' entries from multiple inks entries exposed to normal sunlight and samples stored in the dark were compared. A typical and expected degradation of ink dyes was characterized by the de-alkylation process (loss of CH2– or CH2–CH3 groups). Crystal violet and Victoria blue dye groups, two major dyes used in ballpoint ink industries were thoroughly investigated. In this work, mass spectrometric methods were developed and validated to describe the ageing mechanism of ballpoint ink dyes. Furthermore, factors influencing the aging process (heat, light, natural aging factors) were studied. For real forensic cases the storage conditions of the paper and type of pen used should be known.
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Donato, Filipe Fagan. "Resíduos de agrotóxicos em água potável usando SPE e determinação rápida por LC-MS/MS e GC-MS/MS". Universidade Federal de Santa Maria, 2012. http://repositorio.ufsm.br/handle/1/10528.
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Conselho Nacional de Desenvolvimento Científico e TecnológicoThe use of pesticides always has been associated with the effective control of pests or invasive weeds to ensure an increase in the food production. However, the indiscriminate use of these substances has caused the degradation of water resources. In Brazil, the Ministry of Health through Ordinance 2914 defines several parameters of potability, among them, the maximum limits allowed for same pesticides. In this work it was developed and validated a method for the determination of residues of 70 pesticides in drinking water using (SPE) for sample preparation and determination by Gas and Liquid Chromatography coupled to tandem mass spectrometry, triple quadrupole analyzer (GC-(TQ)MS/MS and LC- (TQ)MS/MS). It was evaluated different sample volume, sorbents and solvent of elution. The best results were obtained using 100 mL sample acidified at pH 2.5, Oasis® SPE cartridge HLB 60 mg/3 mL and dichloromethane/methanol as eluent. Analytical curves were linear between 10 and 250 Sg L-1, with r2 values greater than 0.99 for all compounds. The values of method LOQ were 0.02 Sg L-1 for aldrin, dieldrin and chlordane and 0.5 Sg L-1 for the other compounds. To evaluate accuracy the blank samples ware fortified at 0.5, 1.5 and 4.0 Sg L- 1 and an extra level at 0.02 Sg L-1 for aldrin, dieldrin and chlordane. The method showed good precision, with RSD values below to 20% and good accuracy, with recoveries between 70 and 120%. Only the compounds methamidophos, aldicarb, benfuracarb, terbufos, benomyl and thiophanate methyl were not recovered adequately. The matrix effect was evaluated, showing upper 10% for the most compounds. In order to compensate this effect, analytical curves were obtained with standarts prepared in blank extracts of the matrix. The validated method was applied to 12 samples of drinking water of different characteristics (river, shed, well and treated water), and just one of the river samples presented residues of lambda-cyhalothrin. The results indicate that the proposed method is suitable for analysis of pesticides residues in drinking water, since all the validation parameters met the suggested limits and parameters for validation of chromatographic methods.
O uso de agrotóxicos sempre esteve associado à efetividade no controle de pragas ou plantas invasoras para aumentar a produção de alimentos. No entanto, o uso indiscriminado dessas substâncias vem causando a degradação dos recursos hídricos. No Brasil, o Ministério da Saúde através da Portaria 2914 define diversos parâmetros de potabilidade, entre eles, os limites máximos permitidos para alguns agrotóxicos. No presente trabalho foi desenvolvido e validado um método para a determinação de resíduos de 70 agrotóxicos em água potável, utilizando Extração em Fase Sólida (SPE) para o preparo de amostra e determinação por Cromatografia Gasosa e Líquida, acopladas à Espectrometria de Massas sequencial, com analisador triplo quadrupolo (GC-(TQ)MS/MS e LC- (TQ)MS/MS). Foram avaliados diferentes volumes de amostra, sorventes e solventes de eluição. Os melhores resultados foram obtidos com 100 mL de amostra acidificada em pH 2,5, cartucho SPE Oasis® HLB 60 mg/3 mL e diclorometano/metanol como eluente. As curvas analíticas apresentaram linearidade entre 10 e 250 Sg L-1, com valores de r2 maiores que 0,99 para todos os compostos. Os valores de LOQ do método foram 0,02 Sg L-1 para aldrin, dieldrin e clordano e de 0,5 Sg L-1 para os demais compostos. Para avaliação da exatidão as amostras branco foram fortificadas em 0,5, 1,5 e 4,0 Sg L-1 e um nível extra em 0,02 Sg L-1 para os compostos aldrin, dieldrin e clordano. O método apresentou boa precisão, com valores de RSD inferiores a 20% e boa exatidão, com recuperações entre 70 e 120%. Apenas os compostos metamidofós, aldicarbe, benfuracarbe, terbufós, benomil e tiofanato metílico não foram recuperados de forma adequada. O efeito matriz foi avaliado, mostrando-se superior a 10% para a maioria dos compostos. A fim de compensar este efeito, utilizou-se curvas analíticas preparadas no extrato branco da matriz. O método validado foi aplicado em 12 amostras de água potável de diferentes características (rio, vertente, poço e água tratada), sendo que apenas uma das amostras de água de rio apresentou resíduos de lambda-cialotrina. Os resultados indicam que o método proposto é adequado à análise de resíduos de agrotóxicos em água potável, visto que todos os parâmetros de validação atenderam os limites e parâmetros sugeridos para validação de métodos cromatográficos.
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Ho, Ngoc Huy. "Quantification par LC/MS/MS des formes conjuguées des métabolites de la nandrolone /". Sion, 2006. http://doc.rero.ch/search.py?recid=7938&ln=fr.
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Joyner, Jeffrey Clark. "The Use of 2D-LC-MS/MS in disease characterization and global proteomics". Connect to resource, 2006. http://hdl.handle.net/1811/6604.
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Thesis (Honors)--Ohio State University, 2006.Title from first page of PDF file. Document formatted into pages: contains 46 p.; also includes graphics. Includes bibliographical references (p. 46). Available online via Ohio State University's Knowledge Bank.
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Orives, Andreia Maria Lopes Guermani. "Determinação de amlodipina atraves da tecnica LC-MS-MS em estudo de bioequivalencia". [s.n.], 2004. http://repositorio.unicamp.br/jspui/handle/REPOSIP/311841.
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Orientador: Ronilson Agnaldo MorenoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas
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Resumo: O objetivo deste estudo foi avaliar a bioequivalência de duas formulações de amlodipina em comprimidos ( Amlodipina® 5 mg comprimidos, Laboratório Teuto Brasileiro Ltda., formulação teste e Norvasc ® 5 mg, Laboratórios Pfizer Ltda., como referência ) após administração oral a 24 voluntários adultos sadios de ambos os sexos. O estudo foi aberto, randomizado com duas fases, onde os voluntários receberam uma dose única de besilato de amlodipina 5 mg. As amostras de plasma foram obtidas em um período total de 144 h. As concentrações de amlodipina plasmáticas foram analisadas por um método baseado na cromatografia líquida acoplada ao espectrômetro de massa usando como fonte de ionização eletrospray íon positivo ( LC-MS-MS ) e desipramina como padrão interno. Foram obtidos os seguintes parâmetros das curvas de concentração plasmática x tempo: AUClast, AUCO-inf , AUC0-144h and Cmax. O intervalo estatístico proposto foi de 80 a 125% de acordo com o FDA
Abstract: The aim of this study was to assess the bioequivalence of two amlodipine tablet formulations ( Amlodipine ® 5 mg tablet formulation elaborated by Laboratório Teuto Brasileiro Ltda., Brazil as test formulation and Norvasc ® 5 mg tablet formulation from Laboratórios Pfizer Ltda., Brazil as reference formulation ) after their oral admistration to 24 healthy adult volunteers of both sexes. The study was conducted using an open, randomized two-period crossover design, in which twenty-four healthy volunteers received a single oral dose of amlodipine besylate tablet 5 mg. Plasma samples were obtained over a 144 h period. Plasma amlodipine concentrations were analysed by a method based on liquid chromatography with positive ion electrospray ionization ( LC-MS-MS ) using desipramine as internal standard. From the amlodipine plasma concentration vs time curves, the following pharmacokinetic parameters were obtained: AUClast, AUCO-inf, AUC0-144h and Cmax. The statistical interval proposed was 80 to 125% according to the US Food and Drug Administration Agency
Mestrado
Mestre em Farmacologia
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Zhao, Ruoxia. "Investigation of Ribonucleic Acid Post-transcriptional Modifications by Optimized LC-MS/MS Methods". University of Cincinnati / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1623240214971428.
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Ghezal, Salma. "Etude métabolomique par LC-MS/MS chez Plasmodium Falciparum, parasite responsable du Paludisme". Thesis, Montpellier 2, 2014. http://www.theses.fr/2014MON20179.
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La forme la plus sévère de paludisme est causée par le parasite unicellulaire P. falciparum. Lors de la phase intra-érythrocytaire de son développement, P. falciparum met en place des fonctions métaboliques nécessaires à son développement dans l'érythrocyte, à sa multiplication et enfin à sa dissémination vers d'autres érythrocytes. Comprendre et élucider les structures et les dynamiques du réseau métabolique chez le parasite, permettent de découvrir de nouvelles voies métaboliques et des étapes clefs qui peuvent jouer un rôle important dans le développement du parasite. Elles permettent également de déterminer le mécanisme d'action des agents antipaludiques et de mieux comprendre les résistances associées aux traitements existants. Dans cet objectif, une approche métabolomique ciblée, utilisant la chromatographie liquide couplée à la spectrométrie de masse en tandem (LC-MS/MS) a été utilisée. Cette approche consiste en une quantification absolue de métabolites impliqués dans les voies de biosynthèse des phospholipides membranaires du parasite mais également d'autres métabolites qui reflètent son statut métabolique. Nous avons dans un premier temps, déterminé les distributions et les quantités absolues des métabolites présents dans un érythrocyte infecté par P. falciparum en comparaison avec un érythrocyte sain. Nous avons également mis en évidence les perturbations causées par cette infection sur le métabolisme de l'érythrocyte humain ainsi que les différents échanges qu'entretien le parasite avec sa cellule hôte mais également avec le milieu extracellulaire. Le métabolisme phospholipidique de Plasmodium est complexe car il possède plusieurs voies de synthèses opérant à partir de précurseurs initiaux distincts et conduisant à la synthèse d'un même produit final. Dans l'objectif d'étudier la contribution relative des différentes voies métaboliques dans la biosynthèse des phospholipides majoritaires chez P. falciparum (PC et PE), nous avons développé une approche qui consiste à incuber les érythrocytes infectés en présence de précurseurs marquésThe most severe form of malaria is caused by the single-celled parasite P. falciparum. During the intra-erythrocytic stage of its development, P. falciparum implements several metabolic functions necessary for its development in the erythrocyte, its multiplication and finally to its spread to other erythrocytes. Understand and elucidate the structures and the dynamics of the parasite's metabolic network is useful to discover new metabolic pathways and key steps that may play an important role in the development of the parasite. They also help determine the mechanism of action of antimalarial agents and better understand the resistances associated with available treatments. For this purpose, a targeted metabolomics approach, using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used. This approach consists of an absolute quantitation of metabolites involved in the biosynthesis of membrane phospholipids of the parasite but also other metabolites that reflect its metabolic status. We initially determined the distributions and the absolute amounts of metabolites in infected erythrocytes in comparison with healthy erythrocytes. We also highlighted the disruption caused by this infection on the metabolism of the human erythrocyte and the various interactions between the parasite and its host cell as well as the extracellular medium. The phospholipids metabolism of Plasmodium is complex because it has several synthetic pathways operating from separate initial precursor and leading to the synthesis of a single end product. With the aim to study the relative contribution of these different metabolics pathways in the biosynthesis of the most important phospholipids in P. falciparum (PC and PE), we have developed an approach that involves incubation of infected erythrocytes in the presence of labeled precursors
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Castleberry, Colette M. "Quantitative Identification of Non-coding RNAs by Isotope Labeling and LC-MS/MS". University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1258474676.
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Gallardo, Alcayaga Karem Daniela. "Quantitative profile of lysine methylation and acetylation of histones by LC-MS/MS". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-222245.
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Histone post-translational modifications (PTMs), as the histone code assumes, are related with regulation of gene transcription, an important mechanism of cells in the differentiation process. Many PTMs are simultaneously present in histone proteins, and changes in the PTM stoichiometric ratios can have several effects, like changes in the chromatin structure leading to a transcriptionally active or repressive state. Significant progresses were made to map variations of histone PTMs by mass spectrometry (MS), and although many protocols were developed there are still some drawbacks. Incomplete and side reactions were identified, which can directly affect the quantification of histone PTMs, because both (incomplete and side reactions) can be misinterpreted as endogenous histone post translational modifications.
Therefore, a protocol for derivatization of histones with no noticeable undesired reactions (<10%) was required. In this thesis a new chemical modification methodology is presented, which allows the improvement of sequence coverage by acylation with propionic anhydride of lysine residues and N-terminal (free ε- and α- amino groups) and trypsin digestion. more than 95% of complete reaction was achieved with the new derivatization methodology. This strategy (chemical derivatization of histones), in combination with bottom-up MS approach, allows the quantification of lysine methylation (Kme) and acetylation (Kac) in histones from Saccharomyces cerevisiae (S.cerevisiae), mouse embryonic stem cells (mESCs) and human cell lines. The results showed histone H3 PTM pattern as the most variable profile regarding histone Kme and Kac across the three different organisms and experimental conditions. Therefore, it was concluded that quantification of H3 PTM pattern can be used to examine changes in chromatin states when cells are subjected to any kind of perturbation.
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Paes, Claudia Maria Dias. "Desenvolvimento de método LC/MS/MS para análise multirresíduo de agrotóxicos em café". Universidade Federal de Minas Gerais, 2012. http://hdl.handle.net/1843/SFSA-8YBQJP.
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Coffee is a major tropical agricultural commodity and represents a significant fraction to the economy of many countries. However, unwanted species of plants or animals that cause damage or interfere with the production, transport and storage of coffee can harm their trade. A solution to this is the use of pesticides, which in some cases harm to human health and the environment.
Considering environmental risks and food security, it is necessary the development of performing methodologies to the determination of pesticides residues in coffee. An ideal analytical method must be able to analyze the large number of existing pesticides, without interference of the matriz, to detect and quantify unequivocally the analytes involved at low levels of concentration, accurately and with a small number of measurement that provide time-saving.
This work consisted in the development of a multirresidue method for analysis of pesticides in coffee by high performance liquid chromatography coupled to mass spectrometry (LC/MS/MS). The extraction procedure used was the so-called QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe). The optimizations were carried out in order that the extraction of coffee was efficient and selective.
The following parameters were evaluated: selectivity, analytical range, linearity, limit of detection (LOD), limit of quantification (LOQ), precision (RSD) and recovery of the method. 160 analytes were studied and 128 were validated. The results showed that the method is selective. The best working range was between 10.0 and 100.0 g kg-1. The method presented good linearity with determination coefficients R2 between 0.9922 and 0.9999. The sensitivity, recovery and precision were adequate for the multirresidue analysis of pesticides in coffee. The LOD varied from 0.05-18.48 ìg kg-1 and LOQ varied from 0.11-40.12 ìg kg-1 . The recovery varied between 70 and 120% with values of RSD < 20% .
The method was applied to the analyses of 15 coffee samplesO café é uma mercadoria agrícola tropical de grande importância econômica e representa fração significativa para a economia de muitos países. No entanto, espécies indesejáveis de plantas ou animais que causam danos ou interferem na produção, no armazenamento e no transporte do café podem prejudicar seu comércio. Uma solução para isso é o uso de agrotóxicos, que em alguns casos fazem mal à saúde humana e ao meio ambiente. Considerando os riscos ambientais e a segurança alimentar, é necessário o desenvolvimento de metodologias eficientes e seguras para a determinação de resíduos de agrotóxicos em café. Um método analítico ideal deve ser capaz de analisar o grande número de agrotóxicos existentes, sem interferência da matriz, de detectar e quantificar de forma inequívoca os analitos envolvidos, em baixos níveis de concentração, de forma precisa e com um pequeno número de medidas que proporcione economia de tempo. Este trabalho consistiu no desenvolvimento de um método multirresíduo para análise de agrotóxicos em café por cromatografia líquida acoplada à espectrometria de massas sequencial (LC/MS/MS). O procedimento de extração utilizado foi o denominado QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe). Foram feitas otimizações para que a extração do café fosse eficiente e seletiva. Foram avaliados os seguintes parâmetros: seletividade, faixa de trabalho, linearidade, limite de detecção (LD), limite de quantificação (LQ), precisão (S) e grau de recuperação do método. 160 analitos foram estudados e 128 foram validados. Os resultados mostraram que o método é seletivo. A faixa de trabalho mais adequada estava compreendida entre 10,0 e 100,0 µg kg-1. O método apresentou boa linearidade com coeficientes de determinação R2 entre 0,9922 e 0,9999. A sensibilidade, a recuperação e a precisão mostraram-se adequadas para a análise multirresíduos de agrotóxicos em café. Os LD variaram entre 0,05 a 18,48 µg kg-1 e os LQ entre 0,11 a 40,12 µg kg-1. A recuperação variou entre 70 a 120% com valores de S< 20%. O método foi aplicado à análise de 15 diferentes amostras de café
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Redmond, Amy, Darshan Shah, Jason Pryor e Stacy D. Brown. "Monitoring Buprenorphine and Metabolite Concentrations in Infant Cord Blood by LC-MS/MS". Digital Commons @ East Tennessee State University, 2013. https://dc.etsu.edu/etsu-works/5279.
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Santos, Clarissa Marques Moreira dos. "Espécies de arsênio em moluscos bivalves determinadas por LC-ICP-MS E LC-CVG-ICP-MS após extração assistida por microondas". Universidade Federal de Santa Maria, 2013. http://repositorio.ufsm.br/handle/1/4249.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorIn this work, the aim of this study is to evaluate sample preparation procedures and liquid chromatography-inductively coupled plasma mass spectrometry (LC-ICP-MS) and LC coupled to chemical vapor generation (CVG) and ICP-MS (LC-CVG-ICP-MS) for identification and quantification of As species in mollusks collected in BTS. Conditions related to As species extraction were assessed with the use of microwave assisted extraction (MAE) and ultrasound-assisted extraction (UAE). The influence of the main parameters involved in extraction of As species such as the type and concentration of extraction solution, sample mass, temperature and extraction time were evaluated. The extraction was possible by using water at 80 °C (0.2 g sample and 6 mL of w ater) for 6 min using MAE. For the chromatographic separation the type of mobile phase [(NH4)2CO3 and (NH4)2HPO4] concentration (1 to 20 mmol L-1), pH (5.0 to 9.0), flow rate (1.05 to 1.45 mL min-1) and elution mode (isocratic and gradient) were evaluated. The volume of sample injected into the chromatograph was fixed to 200 μL. For the separation of As species an anion exchange column (Hamilton PRP-X100, 250 x 4.1 mm) was used. Six As species were detected in the mollusks being identified arsenobetaine (AsB), As(III), dimethylarsenic acid (DMA) and ρ- arsanilic acid (ρ-ASA). The best separation of the As species was obtained by gradient elution mode and using the following program: 0 to 1.4 min using 6 mmol L-1 (NH4)2HPO4 to 1.4 to 2.7 min using 20 mmol L-1 (NH4)2CO3 and 2.7 to 15 min using 6 mmol L-1 (NH4)2HPO4). The mobile phase flow rate was set at 1.25 mL min-1. CVG parameters were evaluated and the concentrations of NaBH4 and HCl, and carrier gas flow rate were set to 1.0% (m/v) 1.0 mol L-1 and 1.15 L min-1, respectively. The extraction procedures and determination of total As were evaluated using certified reference materials BCR 627 (Tuna Fish Tissue), DORM-2 (Dogfish Muscle) and NIST 1566b (Oyster tissue). The agreement of the results obtained was 95 ± 3 to 101 ± 5%, respectively. The sum of the concentrations of As species determined by LC-ICP-MS and the total As concentration in digested samples and extracts measured, determined by ICP OES were also in good agreement on a confidence level of 95% (Student t-Test). The developed methods by employing the LC-ICP-MS and LC-CVGICP- MS for As speciation analyses in bivalves mollusks are considered suitable.
Neste trabalho foi avaliado o preparo da amostra e o uso da cromatografia a líquido acoplada à espectrometria de massa com plasma indutivamente acoplado (LC-ICP-MS) e LC acoplado ao sistema de geração química de vapor (CVG) e ICP-MS para a identificação e quantificação das espécies de As presentes em tecidos de moluscos bivalves. Condições relacionadas à extração das espécies de As foram avaliadas com o emprego de extração assistida por micro-ondas (MAE) e ultrassom (UAE). A influência dos principais parâmetros envolvidos na extração das espécies de As, como o tipo e concentração da solução extratora, massa de amostra, temperatura e o tempo de extração por MAE e o tempo de sonicação por US foram avaliados. Extração de As foi possível usando água a 80 °C (0,2 g de amostra e 6 mL de água) durante 6 min com MAE. Para a separação cromatográfica foram avaliados o tipo de fase móvel [(NH4)2CO3 e (NH4)2HPO4], a concentração (1 a 20 mmol L-1), o pH (5,0 a 9,0), a vazão (1,05 a 1,45 mL min-1) e o modo de eluição (isocrático e gradiente). O volume de amostra injetada no cromatógrafo foi fixado em 200 μL. Para a separação das espécies de As foi utilizada uma coluna de troca aniônica (Hamilton PRPX100, 250 x 4,1 mm). Foram detectadas seis espécies de As nos moluscos, sendo identificadas somente a arsenobetaína (AsB), o As(III), o dimetilarsênio (DMA) e o ácido ρ- arsanílico (ρ-ASA). A melhor separação das espécies de As foi obtida por eluição gradiente utilizando as seguintes condições: 0 a 1,4 min empregando 6 mmol L-1 de (NH4)2HPO4, 1,4 a 2,7 min empregando 20 mmol L-1 de (NH4)2CO3 e 2,7 a 15 min utilizando 6 mmol L-1 de (NH4)2HPO4. A vazão da fase móvel foi fixada em 1,25 mL min-1. Os parâmetros de CVG avaliados foram a concentração de NaBH4 e HCl e a vazão do gás de arraste, as quais foram fixadas em 1,0 % (m/v), 1,0 mol L-1 e 1,15 L min-1, respectivamente. Os procedimentos de extração e determinação de As total foram avaliados utilizando os materiais de referência certificados BCR 627 (Tuna Fish Tissue), DORM-2 (Dogfish Muscle) e NIST 1566b (Oyster tissue). A concordância entre os resultados obtidos foi de 95 ± 3 a 101 ± 5%, respectivamente. Os valores entre a soma das concentrações das espécies de As obtidos por LC-ICP-MS e As total nos digeridos e extratos obtidos, determinado por ICP OES também foram concordantes em um nível de confiança de 95% (Teste t-Student). Desta forma, o método desenvolvido empregando LC-ICP-MS e LC-CVG-ICP-MS foi considerado adequado para determinação de espécies de As em moluscos bivalves.
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Kussumi, Tereza Atsuko. "Desenvolvimento de método multiresíduo para determinação de pesticidas benzimidazóis, carbamatos e triazinas em milho por cromatografia líquida acoplada à espectrometria de massas em tandem e sua certificação". Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-13062008-101303/.
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O presente trabalho apresenta os dados obtidos no estudo para o desenvolvimento de método multirresíduo de pesticidas dos grupos de benzimidazol (carbendazim, tiabendazol e tiofanato metílico), carbamatos (aldicarbe, aldicarbe sulfona, aldicarbe sulfóxido, carbaril, carbofurano, metomil, metiocarbe, pirimicarbe, propoxur) e triazinas (atrazina e simazina) em amostras de milho verde. Os pesticidas foram extraídos em acetona, sob agitação, diluídos em água e injetados no sistema LC/MS/MS. A técnica analítica de quantificação e confirmação utilizada foi a Cromatografia Líquida acoplada à Espectrometria de Massas em Tandem com ionização por Electrospray no modo positivo. A validação do método multirresíduo foi submetida em conformidade com a norma EC/2002/657 da Comunidade Européia. Para quantificação dos analitos utillizouse as curvas analíticas dos princípios ativos, nas concentrações que variaram de 0,04 a 8,0 ng/ml, correspondentes a 2,0 a 400 ?g.kg-1 na amostra. Para o estudo da recuperação, os pesticidas foram avaliados em cinco níveis, de ½ Limite de quantificação (LOQ) a 5 LOQ, correspondentes a níveis de fortificação de 4,0 a 200 ?g.kg-1 . Os resultados da recuperação apresentaram, em níveis aceitáveis, na faixa de 80 a 110% e com precisão satisfatórias, CV <=20%, com exceção de aldicarbe e de aldicarbe sulfona. Os limites de quantificação do método variaram de 8 a 40 ?g.kg-1 e os limites de detecção do método, de 0,2 a 2,9 ?g.kg-1. Os limites de quantificação do método atendem aos limites máximos de resíduos da legislação brasileira em vigor. Nas amostras estudadas, não foram encontrados resíduos de pesticidas acima do limite de quantificação do método. Por outro lado, todos os pesticidas, exceto carbaril e pirimicarbe, foram detectados em todas as amostras e em níveis acima dos limites de detecção do método. A alta incidência da presença de resíduos de pesticidas se deve possivelmente ao uso inadequado de agrotóxico, quando não autorizado o seu uso para a cultura de milho no Brasil ou proveniente de alguma contaminação, como o tratamento de agrotóxicos aplicados em outras culturas plantadas no mesmo solo.The present work presents the results of a study of development about a multiresidue method for determining pesticides of the following groups in corn: benzimidazolic compounds (carbendazim, thiabendazol and methyl thiofanate), carbamates (aldicarb, aldicarb sulfone, aldicarb sulfoxide, carbaryl, carbofuran, methomyl, methiocarb, pirimicarb, propoxur), and triazines (atrazine and simazine). The pesticides were extracted in acetone under constant stirring, diluted in water and injected in the LC/MS/MS system. The analytical technique for quantification and confirmation was Liquid Chromatography coupled to tandem Mass Spectrometry with Electrospray ionization in the positive mode The validation of the multiresidue method underwent the European Community EC/2002/657 standard. For the quantification of the analytes, calibration curves of the substances in concentrations ranging from 0.04 to 8.0 ng/mL were used, corresponding to 2.0 to 400 ?g.kg-1 in the sample. For recovery tests, the pesticides were assessed on five levels, from ½ Limit of Quantification (LOQ) to 5 LOQ, corresponding to the fortification levels of 4.0 to 200 ?g.kg-1. The results of the tests showed a recovery of 80-110% with satisfactory precision, and CV <=20%, except for aldicarb and aldicarb sulfone. The limits of quantification of the method ranged from 8 to 40 ?g.kg-1 and the limits of detection ranged from 0.2 to 2.9 ?g.kg-1. The limits of quantification of the method meet the maximum residue limit allowed by the Brazilian law. In the studied samples, pesticide residues above the limit of quantification of the method were not found. On the other hand, all pesticides, except for carbaryl and pirimicarb, in all samples, were detected and level above the limits of detection of the method. The high incidence of residues of these pesticides is probably due to their inadequate use, since it is not allowed on corn cultures in Brazil, or any kind of contamination like the use of such pesticides on other cultures over the same soil.
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Hiba, Abdallah. "Analyse multi-résidus de sulfonamides et de leurs métabolites dans les tissus d’origine animale". Thesis, Pau, 2014. http://www.theses.fr/2014PAUU3034.
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Les sulfonamides sont parmi les antibiotiques les plus couramment utilisés en élevage. Ils peuvent en effet, si leur utilisation n’est pas conduite de manière raisonnable, être une source de nombreux risques pour la santé publique. Au Liban, il n’existe pas à l’heure actuelle de règlementation fixant les limites de résidus des sulfonamides dans les tissus d'origine animale. En outre, aucune investigation sur la présence des résidus des sulfonamides sous leurs formes actives ou métabolisée dans les denrées animales n’a été menée. L'analyse d'une matrice complexe telle que la viande a nécessité la mise en œuvre d’une préparation d'échantillon rigoureuse afin obtenir une analyse reproductible, et suffisamment sensible pour atteindre les limites de détection requises. Cette thèse décrit le développement de deux méthodes analytiques pour la détermination de sulfonamides et de leurs métabolites à l’état de traces dans les tissus d’origine animale (bœuf, volaille, porc…). Elles sont basées sur une étape d'extraction utilisant la méthode QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) suivie d'une analyse par HPLC couplée à un analyseur triple quadripôle MS/MS ou LTQ-Orbitrap Velos. Les performances analytiques de ces méthodes ont été évaluées et comparées. Les méthodes d’analyse ont été validées suivant les recommandations de la décision de l’UE (2002/657/EC) et lors d’une étude de validation inter-laboratoires organisée par FAPAS (Food Analysis Performance Assessment Scheme). Au vu des performances obtenues, une étude de contrôle a été réalisée sur les résidus des sulfonamides et de leurs métabolites dans plus de 300 échantillons de différents tissus d’origine animale dérivant de poulets de chair, bœufs, brebis et porcs collectés dans différentes régions d’élevage libanaisesSulfonamides are amongst the most commonly used veterinary antibiotics. The uncontrolled exposure to sulfonamides upon consumption of meat products can be harmful to human health. In Lebanon, there are no current regulations that specify the safe levels of sulfonamides in animal products. In addition, no studies describing the presence of sulfonamides residues in their active or metabolized form in animal tissues exist. The analysis of residues at trace levels in complex matrices such as meat required the implementation of a rigorous sample preparation and analytical protocol that yields reproducible results at very low concentration levels. This thesis describes the development of two analytical methods for the determination of sulfonamides and their metabolites in animal tissues (e.g. poultry, sheep, pork) at trace levels. They are both based on an extraction step using QuEChERS extraction (Quick, Easy, Cheap, Effective, Rugged and Safe) followed by HPLC. In terms of mass analysers the use of LTQ-Orbitrap Velos and triple quadrupole MS/MS was optimized and the figures of merit were compared. The analytical methods were validated according to the EU decision (2002/657 / EC) criteria and by the participation in an inter-laboratory validation study organized by FAPAS (Food Analysis Performance Assessment Scheme). The methods were applied to carry out a monitoring study to detect and quantify residues of sulfonamides and their metabolites in more than 300 different samples of animal tissues derived from poultry, beef, sheep and pork collected from different regions of Lebanon
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Silva, André Luiz Scridelli. "Otimização do processo fermentativo para produção do antibiótico nigericina por Streptomyces". Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/59/59138/tde-05082014-140438/.
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Metabólitos secundários produzidos por Streptomyces com atividade antibiótica apresentam relevante importância biotecnológica para as indústrias farmacêuticas e agroquímicas. Dentre estes metabólitos, podemos destacar a nigericina, um antibiótico poliéter usado como aditivo em ração animal atuando como promotor de crescimento e no tratamento de algumas doenças, como a malária, em carcinoma nasofaríngeo, a vaccínia, entre outras. Neste trabalho foram avaliadas duas cepas de actinobactérias potenciais produtoras de nigericina, a EUCAL 26 e a EUCAL 74. As duas actinobatérias foram fermentadas em cinco meios de cultivo diferentes (BD, Czapek, ISP2, M29 e TSB). A cepa EUCAL 26 foi a mais promissora na produção de nigericina em meio Czapeck. A partir da EUCAL 26, foi feito um estudo da máxima produção de nigericina em meio Czapek variando o pH do meio, temperatura de fermentação, e período de fermentação. As melhores condições encontradas foram em pH 7,0 a 25 °C por 27 dias. Foi realizado também um estudo de otimização de aumento de escala de fermentação, de um volume de meio Czapeck de 50 mL, para um volume de 4 L. Também foram avaliados dois resíduos agroindustriais (Farmal e Melaço de Soja) para a produção de nigericina. O meio de Melaço de Soja aumento a produção em aproximadamente 300x quando comparado com o meio Czapeck padrão. Os efeitos dos nutrientes do meio Czapeck também foram avaliados. A retida do K2HPO4 do meio produziu um aumento de 50x na produção de nigericina, quando comparado com o meio Czapeck controle. Também foi avaliado o efeito da adição de -butirolactonas sintéticas, moléculas de sinalização hormonal, para a produção de nigericina. Das 15 -butirolactonas testadas, a DP21A foi a mais eficiente, pois além de aumentar a produção de nigericina em 23x, também diminui o período máximo de sua produção. Todas as analises realizadas neste trabalho para o monitoramento da produção de nigericina, foram feitas empregando a espectrometria de massas sequencial acoplada à cromatografia liquida de ultra eficiência.Secondary metabolites produced by Streptomyces with antibiotic activity have significant biotechnological importance for the pharmaceutical and agrochemical industries. Among them, nigericin stands out as an antibiotic polyether used as growth promoter in animal feed and for treatment of some diseases such as malaria, nasopharyngeal carcinoma, and vaccinia. In this study, two actinobacteria strains considered potential producers of nigericin named EUCAL 26 and 74 were tested. The two actinobacteria were fermented in five different culture media (BD, Czapek, ISP2, M29 and TSB). EUCAL 26 strain was the most promising in producing nigericin in amid Czapeck media. For EUCAL 26, a study of maximum production of nigericin in Czapek medium at varying the pH, fermentation temperature and fermentation period have been performed. As a result, the best conditions were pH 7.0, at 25 °C for 27 days. In addition, an optimization study for scale-up fermentation have been done, where a volume of 50 mL Czapeck medium have been expanded to 4 L, in order to obtain the highest production of nigericin. Two agroindustrial residues (FARMAL and Honey Soy) have also been evaluated for nigericin production. The honey soy medium increased nigericin production in the rate of 300 when compared with standard Czapeck medium. The effects of nutrients from Czapeck medium have also been evaluated. Removal of K2HPO4 from culture medium resulted in an increase of 50 times when compared with the control Czapeck medium. The effect of adding synthetics -butyrolactones (hormone signaling molecules) for the production of nigericin have also been evaluated. From 15 tested -butyrolactones, DP21A was the most efficient. In addition to increase nigericin yield in 23x it also reduced the period for its maximum production. All analyzes performed in this study to monitor the nigericin production were performed using tandem mass spectrometry coupled to ultra high performance liquid chromatography.
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Sharp, Julia Lynn. "New Statistical Methods for Analyzing Proteomics Data from Affinity Isolation LC-MS/MS Experiments". Thesis, Montana State University, 2007. http://etd.lib.montana.edu/etd/2007/sharp/SharpJ0807.pdf.
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The field of proteomics is exploding with statistical problems waiting to be explored. To obtain information on protein complexes, interactions between protein pairs is initially examined. This exploration is performed using `bait-prey' protein pull-down assays that use a protein affinity agent and an LC-MS/MS (liquid chromatography-tandem mass-spectrometry)-based protein identifcation method. An experiment generates a protein association matrix wherein each column represents a sample from one bait protein, each row represents one prey protein and each cell contains a presence/absence association indicator. The prey protein presence/absence pattern is assessed with a Likelihood Ratio Test (LRT) and simulated LRT p-values. Fisher's Exact Test and a conditional frequency distribution test using generating functions are also used to assess the prey protein observation pattern. Based on the p-value, each prey protein is assigned a category (Specific or Non-Specific) and appraised with respect to the goal and design of the experiment. The Bayes' Odds is calculated for each prey-bait pair in the `Specific' category to estimate the posterior probability that two proteins interact and compared to an approach used by Gilchrist et al. [23]. The method is illustrated using an experiment investigating protein complexes of Shewanella oneidensis MR-1 at the Proteomics Facility of Pacific Northwest National Laboratory (PNNL). The example analysis shows the results to be biologically sensible and more realistic than methods previously used to infer protein - protein associations. While inferring protein-protein associations is of great importance in proteomic studies, the quality of the data is of equal or greater importance. Protein-protein interactions may be inferred incorrectly or not at all depending on the quality of the data. Prior to this thesis, statistical quality control measures have not been incorporated into these experiments. The implementation of traditional Individual/Moving Range (IMR) charts and cumulative sum (cusum) quality control methods for use with pull-down experiment data is studied. These methodologies are illustrated using a standard protein mixture from PNNL. The joint application of IMR and cusum charts promises to provide researchers with information on changes in the mean and variability of the data resulting from control samples run through the mass spectrometer process.
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Yousef, M. "Analysis of degradation products of drugs and dyes by LC-MS and SFC-MS". Thesis, Swansea University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.636716.
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Chapter one introduces chromatography and mass spectrometry used to conduct experiments in this thesis. An explanation in the importance and ways of implementing the interfacing of high-pressure liquid chromatography and supercritical fluid chromatography with mass spectrometry is briefly summarized. The feasibility of high-pressure liquid chromatography and supercritical fluid chromatography mass spectrometry for the analysis of β-blockers is shown in chapter two. Methods were developed for the separation and analysis of various β-blockers using SFC and HPLC coupled to MS for specificity. The expected advantages of using SFC in relation to HPLC for analysis were not met, resulting in favour of the faster HPLC method. Nevertheless, SFC is complementary to HPLC as it offers advantages in rapidity of method development, reduce cost of purchasing and disposal of solvents. Chapter three demonstrates the investigation into the fading products of Azo dyes using LC-MS. The separation and analysis of standard azo dyes using LC API MS was implemented to observe the behaviour of dyes under these set conditions. The importance in characterisation of impurities at low levels is critical from a customer safety and FDA regulations aspect. Chapter four demonstrates the analysis of two unknown degradation products of methyl-5-aminolevulinate as being related to the degradation of methyl-5-aminolevulinate using high-pressure liquid chromatography mass spectrometry. Finally Chapter five describes the investigation of high-pressure liquid chromatography and supercritical fluid chromatography mass spectrometry in the characterisation of an unknown penicillin G impurity present in batch samples. The impurity in question co-eluted with the main bulk drug and could only be analysed using ion-pair agents.
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Vrobel, Ivo. "Stanovení acetylcholinu pomocí LC-MS ve vzorcích mozkových mikrodialyzátů LC-MS/MS". Master's thesis, 2013. http://www.nusl.cz/ntk/nusl-330085.
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Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Analytical Chemistry Candidate: Ivo Vrobel Supervisors: Prof. RNDr. Petr Solich, CSc; Department of Analytical Chemistry, Faculty of Pharmacy, Charles University in Prague Prof. Seppo Auriola, MSc.(Chem.) Marko Lehtonen; Department of Pharmaceutical Chemistry, School of Pharmacy, University of Eastern Finland in Kuopio Title of master's thesis: LC-MS/MS analysis of acetylcholine in brain microdialysis samples Novel fast and simple LC-MS/MS method of ACh quantification in brain microdialysis samples utilizing stable-isotope-labeled IS was developed. The chromatographic step is based on revered-phase mode of pentafluorophenylpropyl (PFPP) column. The satisfactory retention of ACh is achieved with highly aqueous mobile phase containing 0.05% of the ion-pairing agent TFA and 4% of ACN in 4 min analytical run. Ionization of ACh and IS with low background noise and tolerant towards use of TFA was performed with atmospheric pressure thermospray ionization (APTSI). The selectivity of ACh and IS detection was obtained by SRM modes of MS/MS in the linear ion trap mass analyzer. The performance of developed method was cross validated to the validated method used in the laboratory for ACh measurements. The set of microdialysis...