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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Analysis of organic compounds in the rhizosphere soil of Cyperus rotundus using LC-MS / Analys av organiska föreningar i rhizosfärsjord från Cyperus rotundus med LC-MS

Ruotsalainen, Daniel January 2018 (has links)
Den presenterade studien hade som syfte att utveckla en extraktions-, provpreparerings- och analysmetod för jorden, i vilken gräset Cyperus rotundus växer, i ett försök att identifiera möjliga äggläggningsattraherande ämnen för myggan Anopheles gambiae. Högupplösande vätskekromatografi med hydrofob stationär fas (RP-HPLC, en.) med Masspektrometri med Elektrosprejjonisering (ESI-MS, en.) användes för separation och detektion av de extraherade proverna. Ett flertal extraktionssatser gjordes, där parametrar och tekniker ändrades under utvecklingen av arbetet. Ultraljudsassisterad extraktion (UAE) av jord i en 50:50 (v/v) blandning av metanol och vatten visades vara mest effektiv av de undersökta metoderna. Upprening av jordextraktioner med fastfasextraktion (SPE, en.) visades ha en positiv inverkan på signalintensiteten i kromatogrammen såväl som att reducera intensiteten av de systemtoppar som eluerar vid dödtiden. Detta indikerar att de poläraste ämnena har renats bort. En jämförelse gjordes mellan en extraktion av jord som legat i blöt i fem dagar och jord som extraherats utan att blötläggas. En skillnad kunde ses och visades genom att jämföra kromatogram och masspektra från de två proverna. Tandem-MS-experiment gjordes för ett flertal prekursorjoner med avsikt att identifiera ämnena genom jämförelse med databaserna Human Metabolome Database (HMDB), Metlin och Massbank, men inga överrensstämmande jämförelser kunde göras. Tandem-MS-resultaten användes även för att jämföra efter varandra följande kromatografiska toppar med liknande MS1-spektrum. En identifieringsmetod bör utvecklas innan metoden som presenterats i detta arbete valideras och vidareutvecklas. / The present study aimed to develop an extraction, sample preparation and analysis method for the rhizosphere soil of the grass Cyperus rotundus in an attempt to identify possible oviposition attractants of the Anopheles gambiae mosquito. Reversed Phase High Performance Liquid Chromatography (RP-HPLC) coupled online with Electrospray Ionization Mass spectrometry (ESI-MS) was used for the separation and detection of the extracted samples. Multiple extraction batches were done, altering parameters and techniques along the way. Ultrasound-Assisted Extraction (UAE) of the soil with a 50:50 (v/v) mixture of methanol and water was determined to be the most effective of the attempted methods. Purifying soil extracts with Solid Phase Extraction (SPE) showed to have an impact on the signal intensities in the chromatogram as well as reducing the intensity of system peaks eluting at the dead-time. This indicates that more polar compounds were removed during the SPE purification. A comparison was done between an extraction of soil soaked in water for five days and soil extracted without prior wetting. A difference could be seen and was shown by comparing chromatograms and mass spectra from the two samples. Tandem MS experiments were done for multiple precursor ions in order to identify the compounds by comparison in databases Human Metabolome Database (HMDB), Metlin and Massbank, but no matches in the databases were found. The tandem MS results were also used for comparison of consecutive chromatographic peaks with similar MS1-spectra. An identification method should be developed before the method presented in this work is validated and optimized further.
92

Method Development & Analysis of Seals using FEM / Metodutveckling och analys av tätningar med FEM

Svanborg Östlin, Lovisa January 2023 (has links)
Hyperelasticity is a significant property of rubber, taken advantage of in engineering applications. A common application is the use of seals to prevent fluid transfer (liquid or gas) between solid regions. Volvo CE is often depending on external supplier when developing seals. However, it could be beneficial to be able to do design and analysis in-house. Thus, they want with this master thesis to increase their knowledge about rubber and FEM simulations of seals in ANSYS. The aim with this work is to develop a method and guidelines for analysis and simulation of seals of hyperelastic materials. Components analyzed in this thesis work are two static seals, an O-ring andan in-house modified X-ring design. Selected materials, HNBR and FKM, are commonly used elastomers at Volvo CE. Material tests performed at RISE are for three different load cases:uniaxial tension test, planar tension test and biaxial tension test. Quasi-static analyses are performed in ANSYS. Hyperelastic materials need different constitutive models, hyperelastic material models, to describe their material behavior and these are defined in terms of a strain energy density function.However, the challenge is to determine the material constants in the equation, to characterize the material properties, by processing test data. Research questions answered are ‘’What material tests are needed for hyperelastic materials?’’, ‘’How is the test data converted to work as input to ANSYS and obtain material constants?’’ and ‘’How is an appropriate material model selected for simulation in ANSYS?’’. The study shows the importance of that material test represents the condition the application will experience. It should capture material behavior at the specific frequency, strain amplitude and temperature range for the application. The expected strain range and deformation modes that will play a functional role in the application should be considered in the material testing. Material constants can be determined from test data separately or simultaneously. Test data from at least one deformation mode is required, but one can't accurately predict full deviatoric behavior of hyperelastic material models by using one mode. If data only is used for one deformation mode, simulations in other deformation modes can yield erroneous results. It is therefore recommended to use several deformation modes. For applications with more complex load cases more deformation modes are needed. Generally, recommended tests are uniaxial tension test, planar tension test and biaxial tension test due to homogenous deformation is achieved. It is important to verify the material model before analysis. Using test data from one deformation mode can still provide a good fit. In the cases investigated verifications of the material model Yeoh 3rd order show that the fit obtained by only using uniaxial tension test data and using test data from three tests doesn’t seem to differ. Both uniaxial tension test data and test data from three tests give agood fit when simulating the tests with this material model. The benefit of using test data from three tests is questionable due to costs. It seems that only uniaxial tension test data could have been used as it provided a good fit. Moreover, test data must be processed to work as input to ANSYS. ANSYS requires engineering stress-strain test data for hyperelastic materials besides from the volumetric test, where true stress strain is required. The biaxial tension state which is realized with so called Bulge test thus needs to be converted to engineering stress. Then, test data needs to be adjusted to account for effects such as hysteresis and Mullin’s effect, where choice of curve and a process zero-shift must be done. Hyperelastic material models have different validity for different strain ranges. The selected material model was Yeoh 3rd order, which showed be a good fit for both the materials, HNBR and FKM, in strain range 30 %. The curve fit is based on three tests. The selection was based on the material model with lowest relative error with stability. Material constants were obtained for that material model, and these were used in simulations. Material models tends to be unstable for strains outside the test data. Simulations of seals with fluid pressure were performed for different pressure and stretch of the seal. If the contact pressure is larger than fluid pressure in the seals no leakage will occur. / Hyperelasticitet är en betydande egenskap hos gummi, som används i tekniska tillämpningar. En vanlig tillämpning är tätningar för att förhindra vätskeöverföring (vätska eller gas) mellan fasta områden. Volvo CE är ofta beroende av externa leverantörer vid utveckling av tätningar. De vill därför med detta examensarbete öka sina kunskaper om gummi och FEM-simuleringar av tätningar i ANSYS. Målet med arbetet är att utveckla en metod och riktlinjer för analys och simulering av tätningar av hyperelastiska material. Komponenter som analyseras i detta examensarbete är två statiska tätningar, en O-ring och en intern modifierad X-ringdesign. Utvalda material, HNBR och FKM, är vanliga elastomerer hos Volvo CE. Materialtester som genomförts på RISE är för tre olika belastningsfall: enaxligt dragprov, plant dragprov och biaxialt dragprov. Quasi-statiska analyser genomfördes i ANSYS. Hyperelastiskt material behöver olika konstitutiva modeller, hyperelastsiska materialmodeller, för att beskriva dess materialbeteende och dessa definieras i termer av töjningsenergidensitetsfunktion. Utmaningen är att bestämma materialkonstanterna i ekvationen, för att karakterisera materialegenskaper, genom att processa testdatat. Forskningsfrågor som besvaras är ’’Vilka materialtester är nödvändiga för hyperelastiska material?’’, ’’Hur konverteras testdata för att fungera som indata till ANSYS och erhålla materialkonstanter?’’ och ’’Hur väljs lämplig materialmodell för simulering i ANSYS?’’. Studien visar vikten av att materialtester representerar förhållanden som är representativa för applikationen. Det bör fånga materialbeteendet vid den specifika frekvensen, töjningsamplitud och temperatur för applikationen. Det förväntade töjningsomårdet och deformationslägen som kommer spela en funktionell roll i applikationen bör beaktas i materialtestningen. Materialkonstanter kan beräknas från testdata separat eller simultant. Testdata från minst ett deformationsläge krävs, men man kan inte exakt förutsäga fullständigt devatoriskt beteende hos hyperelastiska materialmodeller genom att använda ett deformationsläge. Om testdata endast används för ett deformationsläge kan simuleringar i andra deformationslägen ge felaktiga resultat. Det är därför rekommenderat att använda flera deformationslägen. Generellt rekommenderade tester är enaxligt dragprov, plant dragprov och biaxialt dragprov då homogen deformation uppnås. Det är viktigt at verifiera materialmodellen innan analys. Att använda testdata från ett deformationsläge kan fortfarande ge en bra passning. I de undersökta fallen visar verifikation av materialmodellen Yeoh 3:e ordningen att passningen som erhållits av enbart enaxligt dragprovtestdata och testdata från tre tester inte skiljer sig åt. Både enaxligt dragprov testdata och testdata från tre tester ger en bra passning när simulerar testerna med den materialmodellen. Fördelarna med att använda testdata från tre tester är ifrågasatt pga. kostnaderna. Det verkar som enbart enaxligt dragprov testdata kunde ha använts då det gav en bra passning. Vidare behövs testdata hanteras för att fungera som indata till ANSYS. ANSYS behöver nominellspänning-töjning testdata för hyperelastiska material förutom för det volymetriska testet, där sannspänning-töjning behövs. Det biaxiala dragprovet som realiserades med s.k. Bulge test måste därför konverteras till nominell spänning. Sedan behöver testdata justeras för att ta hänsyn till effekter som hysteres och Mullins effekt, där val av kurva samt en process ‘’zero-shift’’ måste göras. Hyperelastiska materialmodeller har olika giltighet för olika töjningsområden. Val av materialmodell blev Yeoh 3:e ordningen som visade sig vara en bra passning för båda materialen, HNBR och FKM, i töjningsområden 30%. Kurvanpassningen är baserad på tre tester. Valet baserades på den materialmodell som hade minst relativt fel och som var stabil. Materialkonstanterer hölls för den materialmodellen och dessa användes i simuleringar. Materialmodeller tenderar att vara ostabila för töjningar utanför testdata. Simuleringar av tätningar med flödestryck genomfördes för olika tryck och stretch av tätningen. Om kontakttrycket är större än flödestrycket i tätningen sker inget läckage.
93

Investigating CIC-C1q ELISA for measuring in vitro activation of the complement system on intravenous immunoglobulin / Undersökning av CIC-C1q ELISA för mätning av in vitro-aktivering av komplementsystemet på intravenöst immunoglobulin

Giannoglou, Theodosis January 2023 (has links)
Octapharma tillverkar Octagam, en lösning innehållande humant immunglobulin för intravenös administrering, vars huvudkomponent är immunglobulin G (IgG). Aggregerade IgG förknippas med aktivering av komplementsystemet i frånvaro av antigen. Denna ospecifika aktivering av komplement har tidigare rapporterats orsaka biverkningar hos patienter. För att undvika detta använder Octapharmas laboratorium för kvalitetskontroll en metod som kallas test av antikomplementär aktivitet, för kontroll av batcher av Octagam innan de släpps ut på marknaden. Denna metod har flera problem, t.ex. låg tillgänglighet av viktiga reagens. Syftet med detta projekt var därför att undersöka om en alternativ metod, CIC-C1q ELISA, kunde mäta aktiveringen av komplementsystemet på immunglobuliner genom att testa olika batcher av IgG och värmebehandlade IgG-prover för att bedöma om det fanns en korrelation mellan resultaten från de två metoderna. Resultaten visade att det inte fanns någon korrelation mellan ACA-testet och CIC-C1q ELISA. Varken normala IgG-batcher eller värmebehandlade prover uppvisade någon tydlig korrelation. Den enda fördelen som C1q kan ha är att den gav ett högt resultat för en batch som tidigare har rapporterats orsaka biverkningar hos patienter, medan svaret i ACA-testet var relativt normalt. CIC-C1q ELISA metoden har dock visat sig ha sina egna problem eftersom standardprover ger inkonsekventa värden och mer tester behöver utföras för att hitta spädnings-linjäritet. / Octapharma manufactures Octagam, a liquid preparation of highly purified human immunoglobulin for intravenous administration, the main component of which is immunoglobulin G (IgG). Aggregated IgG is associated with activation of the complement system in the absence of antigen. This non-specific activation of complement has been reported to cause adverse reactions in patients. To avoid this, Octapharma's quality control laboratory uses a method called the determination of anti-complementary activity (ACA) in Immunoglobulin, for control of all batches of Octagam before release. This method has several problems, such as low availability of critical reagents. Therefore, the aim of this project was to investigate whether an alternative method, CIC-C1q ELISA, could measure the activation of the complement system on immunoglobulins by testing different batches of IgG and heat-treated IgG samples to assess whether there is a correlation between the results of the two methods. The results showed that there was no correlation between the ACA test and the CIC-C1q ELISA. Neither normal IgG batches nor heat-treated samples showed a clear correlation. The only advantage the C1q may have is that it gives a high response for a batch that has been reported to cause adverse reactions in patients, while the response in the ACA test was relatively normal. If this can be demonstrated by testing similar batches, it may be beneficial to continue testing the C1q ELISA. However, this method has also been shown to have its own problems, such as the standard sample giving inconsistent values, and more work is needed to find the linearity of the dilution.
94

Разработка методов для увеличения вовлеченности публикаций в Instagram : магистерская диссертация / Developing Methods to Increase the Engagement of Instagram Posts

Слинкина, О. В., Slinkina, O. V. January 2020 (has links)
За последние несколько лет социальные сети для компаний стали одним из основных инструментов работы с клиентами. Социальная сеть Instagram служит инструментом для бизнеса, но из-за высокой конкуренции и медленного обновления функционала сети, существуют проблемы качественной вовлеченности пользователей и автоматизированной работы с социальной сетью. Для решения данных проблем необходимо внедрить специальные инструменты и определить критерии эффективности публикаций в Instagram. Научная новизна. Перечислены актуальные методы для увеличения эффективности публикаций в социальной сети Instagram для бизнеса, выполнена практическая работа с существующими аккаунтами в Instagram, получены новые результаты при отслеживании активности в профилях, выделены новые потребности и задачи, которые должны решать инструменты для работы в Instagram. Практическая значимость исследования – заключается в разработке методов для увеличения эффективности продвижения бизнеса в социальных сетях, которые изложены в учебно-методическом пособие. Представлены данные на основе работы по аккаунту дополнительного образования «Сетевой инженерно-технической школы», подведены и составлены примеры протестированных публикаций. Проанализированы текущие инструменты для работы в Instagram, построена полная модель и выявлены проблемы в модели бизнес-процессов AS-IS. / Over the past few years, social networks have become one of the main tools for working with clients for companies. The social network Instagram serves as a tool for business, but due to high competition and slow updating of the network's functionality, there are problems of high-quality user engagement and automated work with the social network. To solve these problems, it is necessary to introduce special tools and determine the criteria for the effectiveness of posts on Instagram. Scientific novelty. The current methods for increasing the effectiveness of posts on the social network Instagram for business are listed, practical work has been done with existing Instagram accounts, new results have been obtained when tracking activity in profiles, new needs and tasks that must be solved by tools for working in Instagram are highlighted. The practical significance of the study lies in the development of methods to increase the effectiveness of business promotion in social networks, which are set out in the educational and methodological manual. The data on the basis of work on the account of additional education "Networked Engineering and Technical School" are presented, examples of tested publications are summarized and compiled. Analyzed the current tools for working on Instagram, built a complete model and identified problems in the AS-IS business process model.
95

TARGETED AND UNTARGETED OMICS FOR DISEASE BIOMARKERS USING LC-MS

Gorityala, Shashank January 2018 (has links)
No description available.
96

Understanding particulate matter - Material analyses of real-life diesel particulate filters and correlation to vehicles’ operational data / Att förstå partiklar - Analyser av verkliga dieselpartikelfilter och korrelationer till fordonsdriftparametrar

Nordin, Linus January 2021 (has links)
Syftet med denna studie var att undersöka effekterna av driftsparametrar på ett antal mätbara askrelaterade parametrar i dieselpartikelfilter (DPF) i tunga fordon. Tidigare studier visar att askans packningsdensitet, askflöde och hur askan fördelas inuti ett DPF är beroende av parametrar som temperatur, avgasflöde och oljeförbrukning ett fordon har. Det finns anledning att tro att dessa parametrar också påverkas av hur ett fordon används, varför olika driftsparametrar analyserades för korrelation med de uppmätta askparametrarna. De driftsparametrar som undersöktes i denna studie var medelhastighet, antal stopp per 100 km, tomgångsprocent och bränsleförbrukning. Studien startade med metodutveckling av mätning av askvikter hos DPF och jämförde tre olika metoder, benämnda I, II och III. Metod II, som innebar att väga en bit av ett filter före och efter rengöring av filterstycket från aska med tryckluft valdes som den mest pålitliga och användbara metoden eftersom den var snabbare, behövde mindre av varje DPF för att ge kompletta resultat och kunde användas vid analys av DPF-prover som inte hade undersökts innan de användes i ett fordon. Askvikten, tillsammans med den volymetriska fyllningsgraden och genom att känna till inloppsvolymen för ett DPF användes för att beräkna askans packningsdensitet. Fyllningsgraden och askfördelningsprofilen mättes med bildanalys av mikroskopbilder av sågade tvärsnitt av filterstycket. Korrelationsstudien utfördes sedan med dessa metoder och korrelerades med operativa data extraherade från databaser på Scania CV. För att studera vilka parametrar som var korrelerade till varandra utfördes en principal component analysis (PCA) med de operativa och uppmätta variablerna som en matris av data. PCA-analysen visade att tre primalkomponenter (PC) utgjorde >90% av variationen i de erhållna data och att plug/wall-förhållandet, som är ett numeriskt värde för askfördelningen, var starkt positivt korrelerat med ett fordons medelhastighet och negativt korrelerat med antalet stopp, tomgångsprocent och bränsleförbrukning. Vidare visade askflödet en svagare positiv korrelation med tomgångsprocent, antal stopp och bränsleförbrukning medan oljeförbrukningen visade en ännu lägre korrelation med dessa parametrar. Detta indikerar att oljeförbrukningen ej skall ses som en konstant proportionell andel av bränsleförbrukningen för samtliga fordon vid beräkning av serviceintervall för DPFer. Askans packningsdensitet visade ingen till mycket låg korrelation med andra variabler i studien vilket kan bero på att proverna med hög andel väggaska har använts betydligt kortare sträcka än övriga prover, vilket kan ha gjort så att askan inte hunnits packas hårt i filterkanalerna. / The purpose of this study was to investigate the impact of operational parameters on a number of measurable ash related numbers within diesel particle filters (DPFs) of heavy duty vehicles. Previous studies show that ash packing density, ash flow and how the ash is distributed inside a DPF is dependent on parameters such as temperature, exhaust flow profiles and how much oil a vehicle consumes. There is reason to believe that these parameters are also affected by how a vehicle is operated which is why different operational parameters were analysed for correlation with the measured ash numbers. The operational parameters that was investigated in this study was average speed, number of stops per 100 km, idling percentage and fuel consumption. The study started with method development of measuring ash weights of DPFs and compared three different methods, named I, II and III. Method II, which relies on weighing a piece of a filter substrate before and after cleaning the filter piece from ash with pressurized air was chosen as the most reliable and useful method as it was faster, needed less of each DPF to complete the analysis and could be used when analysing DPF samples that had not been investigated previous to its use in a vehicle. The ash weight, together with the volumetric filling degree and known inlet volume of the DPF was used to calculate the ash packing density. The filling degree and ash distribution profile was measured with an image analysis of microscope images of sawed cross sections of the filter piece. The correlation study was then performed with these methods and correlated with operational data extracted from databases at Scania CV. To study which parameters were correlated to each other a primal component analysis (PCA) was performed with the operational and measured variables as a matrix of data. The PCA analysis showed that three primal components made up >90 % of variation in the data and that plug/wall ratio, which is a numerical value of the ash distribution, was strongly positively correlated with average speed of a vehicle and negatively correlated with number of stops, idling percentage and fuel consumption. Furthermore, ash flow showed a slight positive correlation with idling percentage, number of stops and fuel consumption while oil consumption showed an even slighter correlation with these parameters. This indicates that the oil consumption cannot be taken as a constant value as percentage of fuel consumption when calculating service intervals of DPFs. The ash packing density showed none to very low correlation with any other variables in the study, which could depend on the fact that the DPFs with high percentage of wall ash had a significantly lower runtime which could mean that the ash has not had time to be packed tightly in the filter channels.
97

Adsorption and Transport of Drug-Like Molecules at the Membrane of Living Cells Studied by Time-Resolved Second-Harmonic Light Scattering

Sharifian Gh., Mohammad January 2018 (has links)
Understanding molecular interactions at the surfaces of cellular membranes, including adsorption and transport, is of fundamental importance in both biological and pharmaceutical studies. At present, particularly with respect to small and medium size (drug-like) molecules, it is desirable to gain an understanding of the mechanisms that govern membrane adsorption and transport. To characterize drug-membrane interactions and mechanisms governing the process of molecular uptake at cellular membranes in living organisms, we need to develop effective experimental techniques to reach quantitative and time-resolved analysis of molecules at the membrane surfaces. Also, we preferably want to develop label-free optical techniques suited for single-cell and live cell analysis. Here, I discuss the nonlinear optical technique, second-harmonic light scattering (SHS), for studying molecule-membrane interactions and transport of molecules at the membrane of living cells with real-time resolution and membrane surface-specificity. Time-resolved SHS can quantify adsorption and transport of molecules, with specific nonlinear optical properties, at living organisms without imposing any mechanical stress onto the membrane. This label-free and surface-sensitive technique can even differentiate molecular transport at individual membranes within a multi-membrane cell (e.g., bacteria). In this dissertation, I present our current research and accomplishments in extending the capabilities of the SHS technique to study molecular uptake kinetics at the membranes of living cells, to monitor bacteria membrane integrity, to characterize the antibacterial mechanism-of-action of antibiotic compounds, to update the molecular mechanism of the Gram-stain protocol, to pixel-wise mapping of the membrane viscosity of the living cells, and to probe drug-induced activation of bacterial mechanosensitive channels in vitro. / Chemistry
98

[pt] DETERMINAÇÃO DE HIDROCARBONETOS POLICÍCLICOS AROMÁTICOS (HPAS) EM TECIDOS DE ORGANISMOS MARINHOS USANDO EXTRAÇÃO ACELERADA POR SOLVENTE (ASE) COM PURIFICAÇÃO IN-CELL E GC-MS / [en] POLYCYCLIC AROMATIC HYDROCARBON (PAHS) ANALYSIS IN MARINE ORGANISMS TISSUES USING ACCELERATED SOLVENT EXTRACTION (ASE) WITH IN-CELL PURIFICATION AND GC-MS

CAMILLA VIANNA GOMES PINHEIRO 27 June 2024 (has links)
[pt] O objetivo desta pesquisa foi a substituição de técnicas convencionais de extração de amostras para análise hidrocarbonetos policíclicos aromáticos (HPAs) em amostras de tecido para um procedimento confiável, rápido e ambientalmente mais sustentáveis. O novo método foi desenvolvido usando um método de extração com solvente pressurizado, avaliando dois materiais de referência padrão (peixe e mexilhão) e amostras de sardinhas fortificadas (Sardinella sp.). Cinco procedimentos de extração diferentes foram avaliados e o melhor desempenho obtido foi pela extração de 1 g de tecido liofilizado em conjunto com 5 g de sílica desativada (5 por cento), mistura de diclorometano: metanol (4: 1 v / v), temperatura de 80 graus C, três ciclos, 10 min de tempo estático e 90 s de tempo de purga. Este método foi ainda validado pela análise de nove réplicas do material de referência número 2974a(Orgânicos em Tecido de Mexilhão Liofilizado) do National Institute of Standard and Technology (NIST), resultando em uma recuperação média de 85 mais ou menos 14 por cento. As médias e as incertezas obtidos para cada HPA foram equivalentes aos do material de referência, corroborando a confiabilidade do método desenvolvido. Um tempo de processamento mais curto, menos uso de solventes e reagentes e menor manipulação do extrato resultou em um método eficaz e alinhado às diretrizes da química verde. / [en] The aim of this research was the replacement of conventional sample extraction techniques for polycyclic aromatic hydrocarbons (PAH) in tissue samples for a reliable, fast and environmentally more sustainable. The methodwas developed using a pressurized solvent extraction method and assessing two different standard reference materials (fish and mussel) and freeze-dried and fortified sardine samples (Sardinella sp.). Five different extraction procedures were evaluated and the best performance comprised 1 g of lyophilized tissue, 5 g of deactivated (5 percent) silica, a dichloromethane:methanol (4:1 v/v) mixture, a temperature of 80 C degrees, three cycles, 10 min of static time and 90 s of purge time. The method selected following these tests was further validated through the analysis of nine replicates of the National Institute of Standard and Technology (NIST) reference material No. 2974a (Organics in Freeze-Dried Mussel Tissue), resulting in an effective recovery of 85 more or less 14 percent. The means and uncertainties attained for each PAH were equivalent to those of the reference material, corroborating the reliability of the developed method. A shorter processing time, less use of solvents and reagents and lower extract manipulation resulted in an effective method aligned with green-chemistry guidelines.
99

Desenvolvimento e validação de metodologia para determinação de resíduos de pesticidas piretróides por HPLC em feijão / Development and validation of methodology for determination of pyrethroid pesticide residues by HPLC beans

Monteiro, Sérgio Henrique 13 September 2006 (has links)
Um método rápido utilizando cromatografia liquida (LC) foi desenvolvido para determinação simultânea de 7 pesticidas piretróides (bifentrina, cipermetrina, fenpropatrina, fenvalerato, permetrina, lambda-cialotrina, e deltametrina). Os resíduos são extraídos com acetona e a partição realizada de acordo com o método multi-resíduos DFG-S19, substituindo diclorometano por acetato de etila/ciclohexano (1+1) e purificação usando cromatografia de permeação a gel com uma coluna Biobeads SX3 e acetato de etila/ciclohexano (1+1) como eluente. A separação por LC é realizada com uma coluna LiChrospher 100 RP-18 e acetonitrila/água (8+2) como fase móvel. Os pesticidas são detectados em 212nm. As recuperações dos 7 pesticidas piretróides em amostras de feijão fortificadas em 0,010; 0,100; e 1,000 mg/kg ficaram entre 71-105%. A diferença particular deste método é o limite de quantificação, os quais ficaram entre 0,004-0,011 mg/kg, abaixo de muitos outros métodos de LC descritos na literatura. A cromatografia a gás (GC) com detector de captura de elétrons é mais sensível que a LC, mas o método com LC facilita a identificação dos picos. A GC apresenta muitos picos enquanto a LC apresenta apenas um para a maioria dos piretróides. A análise com LC é uma boa alternativa para a determinação de resíduos de piretróides em feijão. Durante o ano de 2005, um total de 48 amostras de feijão comercializadas na cidade de São Paulo, foram analisadas. Nenhum resíduo de pesticida piretróide foi detectado nas amostras. / A rapid liquid chromatographic (LC) method has been developed for simultaneous determination of 7 pyrethroid insecticides (bifenthrin, cypermethrin, fenpropathrin, fenvalerate, permethrin, lambda-cyhalothrin and deltamethrin) in beans. Residues are extracted from beans with acetone and the partition realized according to the multi-residue method DFG-S19, replacing dichloromethane by ethyl acetate/cyclohexane (1+1) and cleaned up using gel-permeation with a Biobeads SX3 column and ethyl acetate/cyclohexane (1+1) as eluant. LC separation is performed on a LiChrospher 100 RP-18 column with acetonitrile/water (8+2) as mobile phase. The pesticides are detected at 212 nm. Recoveries of 7 pyrethroid insecticides from beans fortified at 0.010; 0.100; 1.000 mg/kg levels were 71-105 %. The particular differential of this method is the quantification limits, which were between 0.004-0.011 mg/kg, lower than most of the limits reported for LC methods described in the literature. The gas chromatographic (GC) with electron capture detection is more sensitive than LC, but the LC method facilitates the identification of the peaks. Analysis of pyrethroids by GC shows several peaks, but LC shows only one for most pyrethroids. The analysis by LC was a good alternative for determination pyrethroid residues in beans. During 2005 year, a total of 48 bean samples commercialized in Sao Paulo City were analyzed. No residues of pyrethroids pesticides were detected in the samples.
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Desenvolvimento e validação de metodologia cromatográfica para determinação de bisfenol A em simulantes de alimentos de ensaios de migração / Development and validation of chromatographic method for the determination of bisphenol A in food simulants of migration tests.

Linhares Junior, Gilberto Ferreira January 2012 (has links)
LINHARES JUNIOR, Gilberto Ferreira. Desenvolvimento e validação de metodologia cromatográfica para determinação de bisfenol A em simulantes de alimentos de ensaios de migração. 2012. 101 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Tecnologia de Alimentos, Fortaleza-CE, 2012 / Submitted by Nádja Goes (nmoraissoares@gmail.com) on 2016-06-08T15:09:14Z No. of bitstreams: 1 2012_dis_gflinharesjunior.pdf: 1691103 bytes, checksum: 0abb8d914beb4b36dee06bc962679c7b (MD5) / Approved for entry into archive by Nádja Goes (nmoraissoares@gmail.com) on 2016-06-08T15:09:30Z (GMT) No. of bitstreams: 1 2012_dis_gflinharesjunior.pdf: 1691103 bytes, checksum: 0abb8d914beb4b36dee06bc962679c7b (MD5) / Made available in DSpace on 2016-06-08T15:09:30Z (GMT). No. of bitstreams: 1 2012_dis_gflinharesjunior.pdf: 1691103 bytes, checksum: 0abb8d914beb4b36dee06bc962679c7b (MD5) Previous issue date: 2012 / This study aimed to develop and chromatographic method for the determination of bisphenol A in four different food simulants using high performance liquid chromatography and diode array detector (PDA) to support in enasios migration. The simulating used were A (purified water), B (solution aquosade 3% acetic acid), C (aqueous 10% ethanol) and D (aqueous 95% ethanol). Preliminary assessment of the analytical conditions was conducted in order to establish those that confer the best results, which were the system of mobile phase acetonitrile-water in the ratio 70:30 by volume, 40 ° C oven and length of the column wavelength of 201 nm. The retention time of the bisphenol A was found to be 3.25 minutes. For simulating the method of treatment consists of evaporation of sample 1 ml of sample at 60 ° C with duration of 1 hour and 45 minutes (A and C), 2 hours (B) and 1 hour (D). In sequence, the method was evaluated with respect to the parameters of analytical validation, including linearity, limit of detection and quantification, repeatability, intermediate precision between different analysts and between different days, recovery, selectivity and robustness. The method for simulating the coefficient for determining (r ²) or greater than 0.9988 in the range tested (50 to 2000 ppb); detection limit and quantitation, respectively, 14.7 ppb and 48.9 ppb; coefficient variation in repeatability of 2.07% for the inter-day precision of 1.05% and the accuracy of inter-Analyst 1.76%, recovery of 97.9% (CV = 1.3%) (50 ppb ), 99.2% (CV = 0.7%) (1000 ppb) and 103.6% (CV = 0.4%). The results for the simulant B includes coefficient of determination (r ²) 0.9972 or higher; limit of detection and quantification, respectively, 7.8 ppb and 26.0 ppb; coefficients of variation for repeatability of 3.74%, inter day precision, accuracy and 0.14% cross-Analyst 0.2%, 94.8% recovery (CV = 4.8%) (50 ppb) and 99.8% (CV = 0.2% ) (1000 ppb) and 92.3% (CV = 1.2%) (2000 ppb). For the simulant C results include a coefficient of determination (r ²) 0.9988 or higher; limit of detection and quantification, respectively, 4.8 ppb and 16.1 ppb, coefficient of variation for repeatability of 2.84%, accuracy inter-day precision of 1.37% and inter-analysts of 0.14%; de104 recovery, 6% (CV = 2.5%) (50 ppb), 99.8% (CV = 1.3%) ( 1000 ppb) to 102.5% (CV = 2.9%) (2000 ppb). The results for simulating D was 0.9984 r ² or more, detection limit and quantitation, respectively, 13.7 ppb and 45.6 ppb; coefficient of variation of 2.0% to repeatability, accuracy of an inter-day 9% and accurate inter-de1 analysts, 2%; recuperção 92.6% (CV = 1.76%) (50 ppb) and 99.9% (CV = 0.9%) (1000 ppb) and 104 8% (CV = 2.7%) (2000 ppb). There were no significant interferences to the method tested and proved to be robust. / Este trabalho teve como objetivo o desenvolvimento e metodologia cromatográfica para a determinação de bisfenol A em quatro diferentes simulantes de alimentos utilizando cromatografia líquida de alta eficiência e detector de arranjo de diodo (PDA) para suporte em enasios de migração. Os simulantes utilizados foram A (água purificada), B (solução aquosade ácido acético a 3%), C (solução aquosa de etanol a 10%) e D (solução aquosa de etanol a 95%). A avaliação preliminar das condições de análise foi conduzida com a finalidade de estabelecer aquelas que conferem os melhores resultados, os quais foram o sistema de fase móvel acetonitrila-água na proporção volumétrica 70:30, temperatura de 40°C do forno da coluna e comprimento de onda em 201 nm. O tempo de retenção do bisfenol A encontrado foi de 3,25 minutos. Para os simulantes, o método de tratamento consistiu da evaporação de 1 ml de amostra amostra a 60°C com duração de 1 hora e 45 minutos (A e C), 2 horas (B) e 1 hora (D). Em sequência, o método foi avaliado com relação aos parâmetros de validação analítica, incluindo linearidade, limite de detecção e de quantificação, repetibilidade, precisão intermediária entre analistas diferentes e entre dias diferentes, recuperação,seletividade e robustez. O método desenvolvido para o simulante A apresentou coeficiente de determinação (r²) 0,9988 ou superior no intervalo testado (50 a 2000 ppb); limite de detecção e de quantificação , respectivamente, 14,7 ppb e 48,9 ppb; coeficiente de variação para repetibilidade de 2,07%, para a precisão inter-dias de 1,05% e para a precisão inter-analistas de 1,76%; recuperação de 97,9% (CV= 1,3%) (50 ppb), 99,2% (CV= 0,7%) (1000 ppb) e 103,6% (CV= 0,4%). Os resultados obtidos para o simulante B incluem coeficiente de determinação (r²) 0,9972 ou superior; limite de detecção e de quantificação, respectivamente, 7,8 ppb e 26,0 ppb; coeficientes de variação para repetibilidade de 3,74%, precisão inter-dias de 0,14% e precisão inter-analistas de 0,2%; recuperação de 94,8% (CV= 4,8%) (50 ppb), 99,8% (CV= 0,2%) (1000 ppb) e 92,3% (CV= 1,2%) (2000 ppb). Para o simulante C os resultados incluem coeficiente de determinação (r²) 0,9988 ou superior; limite de detecção e de quantificação, respectivamente, 4,8 ppb e 16,1 ppb; coeficiente de variação para repetibilidade de 2,84%, precisão inter-dias de 1,37%e precisão inter-analistas de 0,14%; recuperação de104,6% (CV= 2,5%) (50 ppb), 99,8% (CV= 1,3%) (1000 ppb) e 102,5% (CV= 2,9%) (2000 ppb). Os resultados para o simulante D foram r² 0,9984 ou superior; limite de detecção e de quantificação,respectivamente, 13,7 ppb e 45,6 ppb; coeficiente de variação para repetibilidade de 2,0%, precisão inter-dias de 1,9% e precisão inter-analistas de1,2%; recuperção de 92,6% (CV= 1,76%) (50 ppb), 99,9% (CV= 0,9%) (1000 ppb) e 104,8% (CV= 2,7%) (2000 ppb). Não foram observados interferentes importantes para o método testado, mostrando-se robusto.

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