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Estudo do equilibrio liquido-liquido, da partição de insulina e da pre-purificação da proteina de fusão precursora da insulina humana em sistemas aquosos bifasicos do tipo PEG/Sal / Study of liquid-liquid equilibrium, the partition of insulin and pre-purification of the fusion protein precursor of human insulin in aqueous biphasic systems of the type PEG / saltAlves, Jose Guilherme Lembi Ferreira 24 March 2003 (has links)
Orientador : Antonio Jose de Almeida Meirelles / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-03T14:52:13Z (GMT). No. of bitstreams: 1
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Previous issue date: 2003 / Resumo: Neste trabalho foi estudada a pré-purificação da proteína de fusão precursora à insulina humana e produzida por Escherichia coli modificada, utilizando-se Sistemas Aquosos Bifásicos do tipo polietileno glicol (PEG)/sal/água. A proteína de fusão foi fornecida pela empresa farmacêutica Biobrás S.A (Montes Claros/MG) e foi dissolvida em uréia 8M. Os experimentos de partição da proteína de fusão foram conduzidos de forma a identificar condições para a separação da proteína de fusão de outras proteínas e componentes celulares de E. coli. Foram realizados dois planejamentos experimentais 32 para o estudo da partição da proteína de fusão precursora da insulina humana no sistema PEG/fosfato de potássio/água. tendo-se como variáveis a massa molar do polietileno glicol, a razão mássica PEG/fosfato do sistema (RPEG/FOS). OS níveis estudados foram 1500, 3350 e 8000 para a massa molar do PEG; 1,6, 1,636 e 1,67 para RPEG/FOS. No primeiro planejamento, os testes de partição foram conduzidos a pH 9, enquanto que no segundo planejamento, os testes foram conduzidos a pH 12. Concluídos os testes com o sistema PEG/fosfato de potássio/água, foi escolhida a melhor condição para a purificação da proteína de fusão, condição esta que foi também testada para o sistema PEG/citrato de sódio/água. Para o sistema PEG/fosfato de potássio/água, o melhor resultado foi obtido com o PEG de massa molar 1500, concentração de 16% p/p PEG/l0% p/p de fosfato e pH 9, com fator de purificação da ordem de 1,5 vez e recuperação de 99%. Nestas mesmas condições, mas utilizando citrato de sódio, o fator de purificação e a recuperação foram 1,8 vez e 50,0%, respectivamente. Para analisar a proteína de fusão precursora da insulina humana, desenvolveu-se uma metodologia de análise por Cromatografia de afinidade / FPLC, usando-se a coluna Chelating Sepharose para separar a proteína de fusão dos demais componentes celulares e o Método de Bradford para quantificá-1a. Diagramas de fase do sistema PE& Na3Cit/H2O, para 3 pesos moleculares de PEG (600, 1500 e 3000) foram medidos a 25°C e modelou-se o equilíbrio líquido-líquido deste sistema usando-se o modelo VERS, baseado na equação do virial e que usa como medida de concentração uma fração de superfície externa do componente. Um ajuste muito bom aos dados experimentais foi obtido e os erros absolutos médios entre as concentrações experimentais dos componentes e as calculadas pelo modelo VERS foram 1,16%, 1,05% e 1,19% para os sistemas PEG600/ Na3Cit/H2O, PEGl500/ Na3Cit/H2O e PEG3000/ Na3Cit/H2O, respectivamente. O modelo obtido apresentou boa capacidade preditiva para a influência da massa molar do PEG sobre o equilíbrio líquido-líquido do sistema estudado. Para fins de modelagem termodinâmica, também foi estudada a partição das insulinas humana e suína puras nos sistemas PEG600/ Na3Cit/H2O, PEG1450/Na3Cit/ H2O e PEG3350/Na3Cit/ H2O em pH 4,5, 7 e 9,5 a 25°C para modelar a partição da insulina no sistema PEG/ Na3Cit/ H2O, utilizando-se também o modelo VERS e bons resultados foram obtidos para a -predição do coeficiente de partição da insulina suína no sistema PEG/ Na3Cit/H2O a pH 7,0 / Abstract: In this work the primary purification of a fusion protein precursor of human insulin and produced by recombinant E. coli has been studied using aqueous two-phase systems. The fusion protein was provided by the pharmaceutical company Biobrás S.A (Montes Claros/Brazil) and was dissolved in 8M area. Partitioning essays of fusion protein were investigated in the poly(ethylene glycol) (PEG)/potassium phosphate and poly(ethylene glycol)/sodium citrate aqueous two-phase systems at 25°C. Two 32 experimental design were done to evaluate the effects of PEG molecular weight and the polymer/salt concentration ratio on the purification factor and on the recovery of the fusion protein in the top phase. The studied levels were 1500, 3350 and 8000 for PEG molecular weight and 1,6; 1,636 and 1,67 for the polymerlsaIt concentration ratio. The partitioning experiments were performed at pH 9 and 12. An analytical method for the fusion protein was developed using Immobilized Metal Affinity Chromatography and the Bradford method. Solids on the interface top were observed in all cases examined The fusion protein partitioned between the PEG-rich phase and the solids on interface. Contaminating proteins were eliminated to some extent, which resulted in an almost 2-fold fusion protein purification with good recoveries. Phase diagrams of the system poly(ethylene glycol)1 sodium citrate/water were determined for three different molecular weights of PEG ( 600, 1500, 3000) at 25°C. At least four tie-lines of each system were measured. The experimental results were correlated by applying a model for the excess Gibbs energy. This model is the Virial equation used by Pitzer for salt solutions, but concentrations are expressed by surface fraction. It is called Virial Equation with Relative Surface fractions (VERS). All phase equilibrium calculations were performed using this model and minimizing the Gibbs energy of the feed under the constraint that both phases are electroneutral. Agreement between the experimental and calculated results within the experimental uncertainty was obtained. The average percents of deviation between experimental and calculated values using VERS model for all components were 1,16%, 1,05% and 1,19% for the systems PEG6001 Na3Cit/H2O, PEGl500/ Na3Cit/H2O PEG30001 Na3Cít/ H2O respectively. Human and porcine insulin partitioning was investigated in the system PEG/sodium citrate/water for three pHs (4,5; 7 and 9,5) at 25°C. Human and porcine insulin showed great affinity for the PEG-rich phase and the partition coefficients were higher than 10. The human insulin partition coefficient is practically independent of the PEG molecular mass. However, there is a tendency for the porcine insulin partition coefficient to increase with the PEG molecular mass at pH 7 and 9,5, attaining values- above 50. The porcine insulin partition coefficient was predicted in the system PEG/sodium citrate/water at 25°C using VERS model and good results were obtained for the system at pH 7 / Doutorado / Mestre em Engenharia de Alimentos
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Equilíbrio líquido-líquido em sistemas-modelos formados por óleo de semente de girassol + aldeídos + etanol anidro a 25 °C sob pressão atmosférica / Liquid-liquid equilibria for the model systems composed by sunflower seed oil + aldehydes + anhydrous ethanol at 25 °C under atmospheric pressureHomrich, Perci Odilon Bonetti, 1989- 03 June 2015 (has links)
Orientador: Roberta Ceriani / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-27T08:35:18Z (GMT). No. of bitstreams: 1
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Previous issue date: 2015 / Resumo: O girassol é a oleaginosa que se apresenta em quarto lugar em relação à produtividade agrícola destinada à obtenção de óleos e possui vantagens por apresentar uma grande quantidade de ácido linoléico (ácido graxo polinsaturado) e compostos nutracêuticos, trazendo benefícios à saúde humana. O óleo de semente de girassol deve passar pelo processo de refino químico para remover a acidez e compostos minoritários para que se torne comestível. O processo de refino químico consiste, basicamente, de quatro etapas: degomagem, desacidificação, branqueamento e desodorização. A etapa de desodorização remove compostos odoríferos (principalmente aldeídos) formados pela oxidação do óleo, além de contaminantes, como pesticidas, por esgotamento com vapor de arraste sob altas temperaturas (até 265 °C) e alto vácuo. Essas condições drásticas de processamento causam a degradação e a volatilização de compostos nutracêuticos (principalmente antioxidantes), além de reações de oxidação e isomerização cis-trans de ácidos graxos insaturados. Neste contexto, este trabalho investigou a possibilidade de pré-tratar o óleo de girassol com solvente, removendo os odores do óleo bruto por extração líquido-líquido, o que possibilitaria uma posterior etapa de desodorização com condições operacionais mais brandas. Para isso, os dados de equilíbrio líquido-líquido para sistemas modelos compostos por óleo de semente de girassol + aldeídos + etanol anidro a 25 ºC foram experimentalmente determinados, sendo os sistemas quantificados por três métodos distintos. A partir dos dados obtidos, os parâmetros coeficiente de distribuição e seletividade do solvente indicaram que a extração dos aldeídos com solvente foi satisfatória, e a correlação dos dados pelos modelos termodinâmicos NRTL e UNIQUAC indicou que o NRTL correlacionou de forma mais fidedigna os resultados, apresentando um desvio global que variou entre 0,4447 e 0,7203 % / Abstract: Sunflower seed oil is the oilseed that represents the fourth major agricultural productivity destined to obtaining refined oils, possessing some advantages due to its high quantity of linoleic acid (polyunsaturated fatty acid) and nutraceutical compounds, promoting benefits to human health. In order to become edible, sunflower oil must be chemically refined for removing free fatty acids and minority compounds. Basically, chemical refining consists of four steps: degumming, deacidification, bleaching and deodorization. The deodorization step removes odoriferous compounds (mainly aldehydes), formed by the oil oxidation reaction, in addition to contaminants, such as pesticides, by a steam stripping under high temperatures (up to 265 °C) and very low pressures. These drastic process conditions result in the degradation and volatilization of nutraceutical compounds (mainly antioxidants), and favor the occurrence of oxidation and cis-trans isomerization reactions of the unsaturated fatty acids. In this context, this work investigated the possibility to pre-treat the sunflower oil with a solvent, removing the crude oil odors by liquid-liquid extraction, which would enable a posterior deodorization stage with milder operational conditions. To achieve this purpose, the liquid-liquid equilibrium data for model systems composed by sunflower seed oil + aldehydes + anhydrous ethanol at 25 °C were experimentally determined and the systems were quantified using three different methods. From the experimental data obtained, the distribution coefficient and the solvent selectivity parameters indicated that aldehydes extraction using ethanol as solvent was satisfactory, and the data correlation done by the thermodynamics methods NRTL and UNIQUAC showed that the NRTL model faithfully correlated the experimental data, presenting a global deviation that varied between 0.4447 and 0.7203 % / Mestrado / Engenharia Química / Mestre em Engenharia Química
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Ésteres etílicos de microalga : equilíbrio e propriedades físicas / Ethyl esters of microalgae : equilibrium and physical propertiesLucchesi, Karolynne Weber, 1985- 27 August 2018 (has links)
Orientadores: Antonio Jose de Almeida Meirelles, Fabio Rodolfo Miguel Batista / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-27T18:12:26Z (GMT). No. of bitstreams: 1
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Previous issue date: 2015 / Resumo: A biomassa de microalgas vem despertando grande interesse científico como matéria prima para produção de biodiesel, devido ao elevado teor de óleo de algumas espécies, além de ser uma importante fonte para a produção de diversos biocompostos. Seu cultivo não compete com a produção de alimentos e ainda auxilia na captura de CO2, tendo um impacto benéfico para o meio ambiente. Diante desta promissora potencialidade, este trabalho objetiva investigar a produção de ésteres etílicos a partir de óleo de microalgas, avaliando as propriedades físicas destes ésteres e do óleo, além de estudar o equilíbrio líquido-líquido de algumas misturas de interesse. Óleo comercial de microalga da espécie Chlorella protothecoides, obtido junto à empresa Solebyo, foi utilizado como matéria prima para a produção do biodiesel (etanol como álcool reagente), obtendo-se um biocombustível totalmente renovável. O óleo foi caracterizado em termos dos seus ácidos graxos, estimando-se sua composição em triacilgliceróis (TAG). A dependência da viscosidade e densidade com relação à temperatura, índice de acidez e teor de umidade, foram determinados para o óleo e seu respectivo biodiesel. Uma análise adicional de ponto de fulgor foi realizada exclusivamente para o biodiesel. Por fim, o estudo do equilíbrio líquido - líquido das misturas biodiesel de microalgas + glicerol + etanol e óleo de microalgas + biodiesel de microalga + etanol, foi realizado a 25, 40 e 55 °C. Estes sistemas têm importância nas diversas etapas da reação de transesterificação e nas etapas de purificação do biodiesel. A técnica de HPSEC foi utilizada para quantificar os componentes nas fases e a modelagem do equilíbrio foi realizada utilizando os modelos NRTL e UNIQUAC. Todos os sistemas apresentaram desvios de balanço menores que 0,5%, indicando uma boa qualidade dos dados experimentais e da técnica utilizada. A grande semelhança entre as propriedades do óleo e do biodiesel de microalgas com relação a óleos e biodieseis convencionais indica uma grande potencialidade desta matéria prima para a produção de biodiesel / Abstract: The biomass of microalgae has been attracting great scientific interest as raw material for biodiesel (fatty acid esters), due to the high oil content of some species, and its importance for biocompounds production. Its great advantage with respect to traditional raw materials (oil) is centered on the fact that the microalgae cultivation does not compete with the food production, especially regarding the production of biofuels, and aids in the capture of CO2, having a beneficial impact to the environment. Given this promising potential, this work aims to investigate the production of ethyl esters from microalgae oil, evaluating the physical properties of these esters and oil, as well as studying liquid-liquid equilibrium of mixtures of interest.For this purpose, commercial microalgae oil of the species Chlorella protothecoides, obtained from Soleybio company, was used as raw material for biodiesel production and ethanol as reagent alcohol, giving to this biofuel a completely renewable character. The oil was characterized in terms of their fatty acids and its composition in triglycerides (TAG) was estimated. The viscosity and density temperature dependence, acidity number and moisture content were determined for oil and its respective biodiesel. Analysis of flash point has been made exclusively for biodiesel. Finally, the study of the liquid - liquid equilibrium of mixtures biodiesel + glycerol + ethanol and microalgae biodiesel + ethanol + oil was performed at 25, 40 and 55 °C. These systems are important in various stages of transesterification reaction and in the steps of biodiesel purification. The HPSEC technique was used to quantify the components at equilibrium phases and the equilibrium modeling was performed using the NRTL and UNIQUAC models. All the systems studied in this work presented balance deviations lower than 0.5%, indicating a good quality of the experimental data and the technique used. The great similarity between the properties of microalgae oil and biodiesel with respect to conventional oils and biodiesels indicate a high potential of microalgae as alternative raw material for the production of biofuels / Mestrado / Engenharia de Alimentos / Mestra em Engenharia de Alimentos
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Microextrações em fase líquida: antimicrobianos em amostras aquosas ambientais / Microextration in liquid phase: antimicrobials in environmental samplesAdriel Martins Lima 14 July 2017 (has links)
Águas residuárias são continuamente contaminadas por fármacos. Dentre estes fármacos, os antimicrobianos causam grande preocupação pelos impactos sobre o desenvolvimento de resistência bacteriana. As principais fontes de contaminação destes fármacos são efluentes urbanos, hospitalares, de fazendas e de algumas indústrias. A complexidade das matrizes ambientais tais como águas residuárias é uma das principais dificuldades para extrair e detectar fármacos, fazendo-se necessário o uso de técnicas de preparo de amostra para a extração destes compostos de interesse. Técnicas clássicas como a extração líquido-líquido (LLE) e a extração em fase sólida (SPE) são largamente usadas para extração de fármacos nesse tipo de matriz, porém estas técnicas não atendem amplamente aos princípios da química verde. Dessa forma, novas técnicas, mais alinhadas à responsabilidade ambiental, têm sido desenvolvidas. Neste âmbito apresenta-se o desenvolvimento e a validação de um método de microextração líquido-líquido para extração e detecção de sulfonamidas e o desenvolvimento e otimização de um método utilizando planejamento experimental para a extração de fluoroquinolonas em águas residuárias. Foi possível obter-se o limite de detecção de 0,2 ng mL-1 para as sulfonamidas analisadas, este LD é relativamente baixo considerando que o detector que foi utilizado não possuía a possibilidade de fazer análises no modo MS/MS, o que certamente reduziria ainda mais o LD. Com os desenvolvimentos desse trabalho tornou-se possível a utilização de apenas 1 mL de solvente orgânico para a pré-concentração off-line, Esta etapa, adicionada a uma outra pré-concentração online (column switching) permitiu a extração dos analitos com a obtenção de um LD relativamente baixo, a partir de apenas 7 mL de amostra. / Drugs are continuously contaminating wastewater. Among these drugs antimicrobials cause great concern for the impacts on the development of bacterial resistance. The main sources of contamination by these drugs are urban effluents, hospitals, farms and some industries. The complexity of the environmental matrices such as wastewater is one of the main difficulties in extracting and detecting drugs, bringing up the need to use sample preparation techniques for the extraction of the interest compounds. Classical techniques such as liquid-liquid extraction (LLE) and solid phase extraction (SPE) are widely used for drug extraction in this type of matrix, but these techniques do not largely meet the principles of green chemistry. In this way, new techniques, more aligned with environmental responsibility, have been developed. In this context, this thesis presents the development and validation of a liquid-liquid microextraction method for sulfonamide extraction and detection and the development and optimization of a method using experimental design for the extraction of fluoroquinolones presented in wastewater. It was possible to obtain a limit of detection (LD) of 0.2 ng mL-1 for the sulfonamides analyzed, this LD is relatively low considering that the detector that was used did not have the possibility to perform analyzes in the MS/MS mode, which certainly would further reduce the LD. With the development of this thesis, it became possible to use only 1 mL of organic solvent for the off-line preconcentration of the analytes. This step, added to another online preconcentration (column switching) allowed the extraction of the analytes obtaining relatively low LDs, from just 7 mL of the sample.
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CaMKII activation triggers persistent formation and segregation of postsynaptic liquid phase / CaMKIIの活性化によるシナプス後部液相の持続的な形成と分離Liu, Pin-Wu 23 March 2021 (has links)
京都大学 / 新制・課程博士 / 博士(医科学) / 甲第23115号 / 医科博第126号 / 新制||医科||8(附属図書館) / 京都大学大学院医学研究科医科学専攻 / (主査)教授 伊佐 正, 教授 髙橋 良輔, 教授 井上 治久 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM
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Optimisation de molécules extractantes pour le multi-recyclage du Plutonium dans les combustibles de nouvelle génération. / Extracting molecules optimization for Plutonium multi-recycling in new generation fuels.Berger, Clémence 23 July 2019 (has links)
Ces travaux de thèse, effectués dans le cadre des études sur le retraitement des combustibles nucléaires usés par extraction liquide-liquide, concernent l’évaluation des performances d’extraction d’une nouvelle famille de molécules : les carbamides (R1R2NC(O)NR3R4). Cette famille peu étudiée jusqu’à maintenant apparait comme pertinente pour la séparation chimique de l’uranium et du plutonium à partir d’une solution d’acide nitrique concentrée. Le procédé envisagé permettrait une co extraction de l’uranium et du plutonium à forte concentration d'acide nitrique (4 mol.L 1) ainsi qu’une séparation de ces deux éléments à plus faible concentration d'acide nitrique (0,5 mol.L-1) sans avoir recours à des réactions d’oxydo-réduction comme c’est le cas pour le procédé industriel PUREX actuellement mis en œuvre dans les usines de retraitement de La Hague.En vue de l’optimisation de la structure de ces nouveaux extractants, 17 carbamides ont été étudiés. L’influence de la longueur des chaînes alkyle, du nombre de substituants, du nombre et de la position de ramifications a été évaluée sur l’extraction de l’uranium et du plutonium ainsi que sur la sélectivité U/Pu. Les résultats ont montré que certains carbamides sont des extractants performants vis-à-vis de l’uranium. La présence d’un groupement –NH sur la fonction carbamide améliore l’extraction alors que l’ajout de ramifications sur les chaines alkyles diminue l’extraction ainsi que la séparation U/Pu. Des études complémentaires sur la capacité de charge et la viscosité ont permis d’optimiser la structure et de proposer des candidats répondant aux critères de développement d’un procédé.La spéciation de l’uranium et du plutonium en phase organique en fonction de divers paramètres (structure du carbamide, concentration d'acide nitrique, etc) a mis en évidence les différents complexes formés: UO2(NO3)2L2; UO2(NO3)3(HL) et {UO2(NO3)L2}(NO3)pour l’uranium et Pu(NO3)4L2 et Pu(NO3)6(HL)2 pour le plutonium. Un lien entre les différences de propriétés extractantes et la nature des complexes formés en phase organique a été mis en évidence. En particulier, un changement du mécanisme d’extraction de l’uranium est observé pour les composés portant le groupement –NH. Par ailleurs, l’augmentation de la concentration d’acide nitrique en phase aqueuse favorise fortement la formation des complexes où l’extractant est en sphère externe UO2(NO3)3(HL) et Pu(NO3)6(HL)2 en solution.Enfin la stabilité de ces extractants vis-à-vis de la radiolyse a été étudiée de manière préliminaire. / This thesis, conducted in the framework of the reprocessing of spent nuclear fuels by solvent extraction, concerns the extraction performances evaluation in view of new extractants optimization: carbamide molecules (R1R2NC(O)NR3R4). This extractant family has not attracted much attention in literature but appears as a good substitutes for the chemical separation of uranium and plutonium from an nitric acid aqueous phase. The considering process will allow to extract uranium and plutonium at high nitric acid concentration (CHNO3aq = 4 mol.L-1) and separate these two elements at lower nitric acid concentration (CHNO3aq = 0,5 mol.L-1) without redox chemistry.In these conditions, 17 carbamide extractants were studied to observe the influence of alkyl chains length, substituent number, position and number of (2-ethylhexyl) ramifications on the uranium and plutonium extraction and on the U/Pu selectivity. Results indicate a high uranium extraction by carbamide molecules. Moreover, substituent number have a high influence on the cations extraction whose distribution ratio highly increase with the –NH group presence on the carbamide function. On the other hand, ramifications addition decrease the extraction and the U/Pu separation with the decreasing of distribution ratios. Additional studies on loading capacity and viscosity measurements allow to optimize the structure and some good analogs are proposed to process development.The uranium and plutonium speciation in organic phase as a function of experimental conditions (carbamide structure, nitric acid concentration, etc) allow to highlight formed complexes: UO2(NO3)2L2; UO2(NO3)3(HL) and {UO2(NO3)L2}(NO3) for uranium and Pu(NO3)4L2 and Pu(NO3)6(HL)2 for plutonium. The relation between extracting properties and formed complexes in organic phase has been made. In particular, modification of the uranium extraction mechanism is observed for the compounds containing –NH group. Moreover, the increase of aqueous nitric acid concentration have a favorable effect on the formation of outer sphere complexes UO2(NO3)3(HL) and Pu(NO3)6(HL)2.Then extractant stability of extractant regarding γ radiolysis have also been studied
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Validation and comparison of three sample preparation techniques for quantitation of amobarbital, butalbital and phenobarbital in blood and urine using UFLC-MS/MSChan, Chi Hin 09 October 2019 (has links)
This research study successfully completed three objectives: 1) validate liquid-liquid, supported-liquid, and solid-phase extractions for the quantitation of three barbiturates (amobarbital, butalbital, and phenobarbital) in blood and urine using liquid chromatography-tandem mass spectrometry; 2) to compare the efficiency and effectiveness among methods in accomplishing extraction of barbiturates under the laboratory setting at Boston University School of Medicine; and 3) to report all the analytical data to RTI International for interlaboratory comparison.
For the validation study, a six-point linear calibration model (20-2000 ng/mL) with inversely weighted concentration (1/x) was reproducible in all three sample preparation methods for both blood and urine with r2 greater than or equal to 0.994. Bias and precision evaluated from three controls throughout the range of the curve were within ±20% and ±20%CV, respectively. Neither carryover nor interference was observed. Detection limits were evaluated down to 5 ng/mL depending on the extraction procedure. Samples were able to be diluted up to 50 times prior to instrumental analysis. Samples were stable on autosampler at room temperature up to 72 hours after their initial analysis. Recovery of barbiturates from blood and urine all ranged from 45% to 86%. The effect of ionization suppression or enhancement was found to have minimal impact on the validation.
For choosing the most suitable method quantifying barbiturates, efficiency and effectiveness were studied. Efficiency evaluates the time and ease of sample preparation required to prepare a sample for analysis. Supported-liquid extraction was found to be the most efficient method for extracting barbiturates as it required the least amount of time to perform and could be easily automated with minimal training. Effectiveness is an assessment of one’s ability to selectively recover target analyte at a reasonably low concentration. By considering a method’s recovery, extract cleanliness, detection limits, and reproducibility, liquid-liquid extraction was the best at quantifying barbiturates in blood and supported-liquid extraction was the most suitable method for extracting barbiturates from urine.
For interlaboratory comparison, all the data collected has been reported to RTI International. These findings can be used for examining the overall reliability and reproducibility of the validated methods. Results obtained can also be used to explore the possibility for streamlining sample preparation in the forensic laboratory, and hence reducing the case backlog.
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Evaluation and comparison of various sample preparation techniques for the analysis and quantitation of THC, synthetic cannabinoids, and metabolites by LC-MS/MS in human whole blood and urineBoyle, Sarah 09 October 2019 (has links)
A cannabinoid refers to any natural or synthetic compound that interacts with the CB1 and CB2 receptors. There are currently three different groups of cannabinoids: endogenous cannabinoids, phytocannabinoids and synthetic cannabinoids. The most common phytocannabinoid is delta-9-tetrahydrocannabinol (THC), which is the active component in the Cannabis sativa or marihuana plant1–3. Two examples of synthetic cannabinoids that are present in case reports from 2012 to 2018 are AB-FUBINACA and AB-PINACA4–7.
THC and synthetic cannabinoids are commonly encountered drugs in forensic toxicology cases, therefore, being able to extract these compounds and their metabolites is imperative for toxicological interpretation. There are a variety of commercially available sample preparation techniques for these analytes. Companies such as UCT, Biotage, Millipore-Sigma, Tecan, and Thermo Fisher Scientific manufacture these products. The focus of this research was to evaluate these techniques for their cleanliness, efficiency and cost effectiveness. Sample preparation techniques are designed to remove the different components of the matrix and other prescription or illicit substances present in the sample that could interfere with the assay, increase the analyte recovery, extraction efficiency, decrease variability, and clean-up the sample to allow for less instrument downtime and longer column life8. This study focused on comparing a liquid-liquid extraction (LLE), solid phase extraction (SPE), and supported liquid extraction (SLE).
The primary purpose of this study was to develop and validate the three above mentioned sample preparation techniques for the analysis of THC, 11-hydroxy-THC, 11-nor-9-carboxy-THC (THCCOOH), AB-FUBINACA, AB-FUBINACA metabolite 3, and AB-PINACA in blood and urine.
Parameters assessed followed Academy Standards Board (ASB) Standard 036, Standard Practices for Method Validation in Forensic Toxicology, including recovery, suppression, and matrix effects.
For urine and blood analysis, the calibration range was determined to be 1 ng/mL to 50 ng/mL for all three techniques. Urine recovery was highest for the LLE method, with all compounds having a recovery greater than 50%. The SLE method had the lowest LOQ results for urine, with 0.5 ng/mL for 11-hydroxy-THC and THCCOOH, 0.75 ng/mL for THC, AB-FUBINCA and AB-FUBINACA metabolite 3, and 1 ng/mL for AB-PINACA. Ion suppression was reduced using the SLE method for urine along with having the shortest sample preparation time of 1 hr for up to 48 samples.
For blood analysis, the LLE method had the greatest recovery of all analytes. The LLE method also had reduced suppression and matrix effects compared to the SPE method. Sample preparation was shorter for the SPE method, consuming 2 hrs for an average sample batch, compared to 4 hrs for the LLE method, which included a 2 hr freezing step.
In conclusion, for urine analysis, all three sample preparation techniques were acceptable for the analysis of THC, synthetic cannabinoids, and their metabolites, with the SLE method being the preferred method. For blood analysis a LLE and SPE method were developed and are adequate for the analysis of THC, synthetic cannabinoids, and their metabolites, with the LLE method being the preferred method.
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Comparison of sample preparation techniques on twenty-three drugs in human whole blood and urineMcGowan, Courtney K. 10 October 2019 (has links)
In forensic toxicology, analysis of drugs and metabolites in biological fluids is performed to determine cause of death, suspected drug use, drug facilitated sexual assaults, or whether someone was driving under the influence. Analyte identification and concentration determination can be determined in a variety of matrices (e.g., blood, urine, or oral fluid) and can be complex. It is therefore necessary to have optimal sample preparation and instrumental conditions that work for all matrices of interests. Determining the best approach can be challenging due to the amount of time and resources to perform expansive evaluations of sample preparation, stationary/mobile phases, liquid chromatography (LC) conditions and mass spectrometry (MS) operating parameters.
In this study three different sample preparation methods were validated for blood and urine. The three sample preparation methods were solid-phase extraction (SPE), supported liquid extraction (SLE), and liquid-liquid extraction (LLE). Six different drug groups were used as the analytes being tested by the methods. These drug groups were amphetamines, local anesthetics, opioids, hallucinogens, antidepressants, and novel psychoactive substances (NPS). A total of twenty-three drugs were used: amphetamine, methamphetamine, (3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxy-N-ethylamphetamine (MDEA), and 3,4-methylenedioxymethamphetamine (MDMA), benzoylecgonine (BZE), cocaine, lidocaine, codeine, methadone, morphine, 6-monoacetylmorphine (6-MAM), fentanyl, oxycodone, lysergic acid diethylamide (LSD), phencyclidine (PCP), amitriptyline, citalopram, fluoxetine, trazodone, ethylone, α-pyrrolidinopentiophenone (α-PVP), and 25I-NBOMe.
The methods were validated according to guidelines set forth by the Scientific Working Group for Forensic Toxicology (SWGTOX) Standard Practices for Method Validation in Forensic Toxicology and the American Academy of Forensic Science (AAFS) Standards Board (ASB) draft of Standard Practices for Method Validation in Forensic Toxicology. Parameters of calibration model, bias, precision, limit of detection (LOD), limit of quantitation (LOQ), dilution integrity, ion suppression/enhancement, interference studies, and stability were evaluated. Recovery was also assessed to determine the efficiency of the extraction. Calibration models met the 0.98 R2 minimum requirement. For all sample preparations the compounds evaluated in each were found to be stable for at least 72 hours. Interferences were found to be similar across all three sample preparation methods. Parameters of bias, precision, and dilution integrity were largely comparable between all three methods. Overall for LOD, SLE resulted in lower values for blood and urine ranging for 0.1 to 5 ng/mL. Overall for LOQ, SLE resulted in lower values for blood and LLE resulted in lower values for urine in the range of 0.5-10 ng/mL. SLE resulted in the highest recovery for all twenty-three analytes, due to LLE failing to extract consistently or completely for benzoylecgonine, morphine, and 6-monoacetylmorphine. Overall, SLE resulted in the lowest percent values for ion suppression and enhancement for both blood and urine. Overall, blood resulted in high ion suppression (exceeding -20%) for SPE and LLE.
Final determination overall was that SLE was the best sample preparation method for all twenty-three analytes. This was determined based on the evaluation of recovery, ion suppression/enhancement, and LOD, as well as sample preparation time. Sample preparation time for SLE was approximately 1 hour, while SPE took 2.5 hours and LLE 2 hours.
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Pathological Aggregation and Liquid-Liquid Phase Separation of TDP-43 in Neurodegenerative DiseaseBabinchak, William Michael 29 May 2020 (has links)
No description available.
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