Дисертації з теми "UV-VIS detector"
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Bhattacharryya, Saroj Kumar. "Development of detector for analytical ultracentrifuge. - [korr. Fassung]." Phd thesis, Universität Potsdam, 2006. http://opus.kobv.de/ubp/volltexte/2006/821/.
It became obvious that with the generation of data in 3-D space in the UV/Vis detection system, the user can select the wavelength for the evaluation of experimental results as the data set contains the whole range of information from UV/Vis wavelength. The detector showed the data generation with much faster speed unlike the commercial instruments. The advantage of fast data generation was exemplified with the evaluation of data for a mixture of three colloids. These data were in conformity with measurement results from normal radial experiments and without significant diffusion broadening. Thus conclusions were drawn that with our designed Multiwavelength detector, meaningful data in 3-D space can be collected with much faster speed of data generation.
In der vorliegenden Arbeit wurde die Entwicklung neuer Detektoren für die Analytische Ultrazentrifugation (AUZ) untersucht und vorangetrieben. Im Gegensatz zu chromatgraphischen. Fraktionierungsmethoden werden Multidetektionssysteme bis heute nicht in der AUZ eingesetzt. Hier wird die Möglichkeit geprüft, bekannte spektroskopische sowie Streumethoden simultan zur Probenanalyse in der AUZ einzusetzen mit dem Ziel, simultan komplimentäre Informationen über die Probe zu erhalten. So wurde versucht, Raman- und UV/VIS-Spektroskopie (letztere mit der Möglichkeit, das gesamte Wellenlängenspektrum auszunutzen) und statische Lichtstreuung zu kombinieren, um das Analytverhalten während des Ultrazentrifugationsexperimentes zu untersuchen. Es wurden zum einen die Ramanspektroskopie als Detektionssystem für chemische Funktionalität in der AUZ geprüft und zum anderen gezeigt, daß die statische Kleinwinkel Lichtstreuung als direkter Molmassendetektor für den Einsatz in der AUZ geeignet erscheint. Zum anderen wurde die Entwicklung eines Multi-Wellenlängen-UV/VIS-Detektors abgeschlossen, um seine Eignung für den Einsatz in der AUZ und die damit verbundene Möglichkeiten der schnelleren und umfassenderen Datenerzeugung gegenüber kommerziellen Geräten zu zeigen. Dieser Multiwellendetektor liefert anstelle eines Absorptionswertes für jede radiale Position in der Messzelle direkt ein ganzes UV-Vis Spektrum und erzeugt eine zusaetzliche Dimension der Messdaten, was die Möglichkeiten der Analyse von komplexen Systemen mit multiplen Chromophoren, Teilchengrößenbestimmung über Wellenlängenabhängigkeit der Trübung oder auch der Datenmittelung enorm vergrößert. Desweiteren erlaubt der Detektor die Anwendung von Geschwindigkeitsprofilen zur Analyse extrem polydisperser Systeme. Die Entwicklung des Detektors beruht auf einem auf Linsen basierenden System mit modularem Aufbau. Dabei war die sorgfältige Ausrichtung des optischen Systems ein essentieller Punkt, um seine Eignung zu überprüfen zu können. An einer Mischung von drei Kolloiden, Halbleiternanopartikeln sowie Proteinen und deren Mischungen ist es hier gelungen, die erfolgreiche Entwicklung des UV/VIS-Detektors zu demonstrieren: Die Daten konnten schneller und mit wesentlich mehr Informationsgehalt, als auf allen kommerziellen Geräten generiert werden. Die Sedimentationskoeffizientenverteilungen stimmen dabei mit denen aus herkömmlichen Sedimentationsgeschwindigkeitsexperimenten überein, unterliegen jedoch nicht einer signifikanten diffusionsbedingten Verbreiterung. Es ist in dieser Arbeit somit gelungen, zum einen die Lichtstreuung als aussichtsreiche Methode für ein Detektorsystem in der AUZ aufzuzeigen, und zum anderen einen Multi-Wellenlängen-UV/VIS-Detektor zu entwickeln, der eine Datenerzeugung von bislang noch nicht erreichter Schnelligkeit im dreidimensionalen Raum ermöglicht.
Ishikawa, Aline Akemi. "Desenvolvimento e validação de método para análise do topiramato em amostras de plasma por eletroforese capilar com detecção UV/vis e C4D." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/60/60134/tde-06072016-104515/.
Topiramate (TPM) is an antiepileptic drug that has been used as an agent for the control of partial and generalized seizures in both adults and children patients. The determination of the plasmatic concentration of TPM in association with clinical observations is of utmost importance for the individual adjustment of the administered dose to the patient. In the present work, two bioanalytical methods have been developed and validated for TPM analysis in plasma samples by capillary electrophoresis using DAD (indirect detection) and C4D Lite detectors (conductometric detection). The electrophoretic analysis for both methods were performed on a fused silica capillary of 75 ?m of internal diameter and 40 cm effective length. The background electrolyte was composed of triethanolamine (TEA) 15 mmol L-1 for conductometric detection and TEA 15 mmol L-1, 3,5 dinitrobenzoic acid (DNB) 5 mmol L-1 and cetyltrimethylammonium bromide (CTAB) 0.4 mmol -1 for indirect detection. The injections were carried out in hydrodynamic mode, at 0.8 psi for 5 seconds, and the voltage applied were -20 e 20 kV for indirect and conductometric detection, respectively. Under these conditions, TPM migrated in 2.5 min. The sample preparation was carried out by liquid liquid extraction (LLE) using methyl tert-butyl ether (MTBE) as solvent, and using 500 and 200 ?L of plasma samples for direct and conductometric detection, respectively. The methods were validated according to the official guides of the Agência Nacional de Vigilância Sanitária and European Medicine Agency, and showed linearity in plasmatic concentration range of 1-30 mg L-1, precision and accuracy values below 15%, beside selectivity. Both methods have been applied successfully to analysis of plasma samples of patients in treatment with TPM. Although universal detectors have a higher quantification limit compared with selective detectors, the method with conductometric detection developed in this work presented greater sensitivity than indirect method (DAD). Furthermore, it also presented advantages such as simplicity and low cost, showing feasibility in applying to routine analysis.
Sloupová, Klára. "Izolace čistých aminokyselin z pšeničných otrub." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2021. http://www.nusl.cz/ntk/nusl-449764.
Fróes, Márcia Beatriz Reis. "Desenvolvimento de método para determinação de resíduos de pesticidas em frutas exóticas por dispersão da matriz em fase sólida e cromatografia líquida de alta eficiência com detector espectrofotométrico de absorção no UV-VIS com arranjo de diodos." Universidade Federal de Sergipe, 2010. https://ri.ufs.br/handle/riufs/6057.
As frutas constituem uma excelente fonte de alimentação, proporcionando importantes benefícios à saúde. O consumo de frutas com novos sabores e características nutricionais elevadas, chamadas de superfrutas, tem sido uma tendência mundial, entre elas se encontram o açaí e o cupuaçu. A presença de resíduos de pesticidas em alimentos constitui um risco a saúde da população, sendo importante o estudo de métodos analíticos para a determinação de seus resíduos. A literatura não registra método para a determinação de pesticidas em açaí e cupuaçu. Neste contexto, este trabalho tem como objetivo o desenvolvimento de um método baseado na MSPD e HPLC-UV/DAD para a determinação dos pesticidas bromuconazol, fenbuconazol, parationa-metílica, cresoxim-metílico e teflubenzuron em frutas exóticas, açaí e cupuaçu. O método de extração por dispersão da matriz em fase sólida foi desenvolvido, testando-se diferentes tipos e quantidades de suporte sólido (alumina neutra, Florisil, sílica e C18) e os solventes orgânicos (15 a 30 mL) acetato de etila, diclorometano, ciclohexano e acetonitrila. Os melhores resultados para os pesticidas bromuconazol, fenbuconazol, parationa-metílica e cresoxim-metílico em análise por HPLC-UV/DAD foram obtidas na utilização da proporção 1:3 (m/m) amostra:suporte sólido do solvente alumina neutra, sem etapa de limpeza (clean-up), e eluição com 20 mL de acetato de etila:ciclohexano na proporção 1:1, v/v. Para a matriz açaí, valores de recuperação entre 57-119 % e valores de coeficientes de variação na faixa de 1,4-20 % para os níveis de concentração 1, 2 e 6 μg mL-1, com limites de detecção e quantificação do método entre 0,1- 0,9 μg g-1 e 0,4 -2,1 μg g-1 , respectivamente. Para a matriz cupuaçu, valores de recuperação entre 57 - 69 %,ao nível de concentração de 2 μg g-1.
Lien, Wan-Fu. "Separation of Transition Metal Ions by HPLC, Using UV-VIS Detection." Thesis, North Texas State University, 1987. https://digital.library.unt.edu/ark:/67531/metadc501145/.
Williams, Elizabeth Mary. "Oxidation of human nitrosylhemoglobin monitored by UV-Vis and EPR Spectroscopies: detection of products and intermediates." Thesis, Montana State University, 2005. http://etd.lib.montana.edu/etd/2005/williams/WilliamsE0805.pdf.
Newkirk, Scott Hunter. "Detection levels of drinking water contaminants using field portable ultraviolet and visible light (uv/vis) spectrophotometry /." Download the thesis in PDF, 2005. http://www.lrc.usuhs.mil/dissertations/pdf/NEWKIRK2005.pdf.
Liao, Jing-Piin. "Investigation of Copper-Natural Ligand Complexes by RP-HPLC Photodiode Array UV-VIS and Fluorescence Detection." Thesis, University of North Texas, 1992. https://digital.library.unt.edu/ark:/67531/metadc332502/.
Špačková, Simona. "Optimalizace metody pro stanovení anorganických iontů za využití kapilární elektroforézy." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2021. http://www.nusl.cz/ntk/nusl-449419.
Buchtová, Zuzana. "Stanovení karnitinu v potravních doplňcích." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2008. http://www.nusl.cz/ntk/nusl-216435.
Cobbs, Ashley L. "Detection of Barium and Strontium Ions in Water Utilizing Functionalized Silver Nanoparticles." Ohio University Honors Tutorial College / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1588098171596986.
Müller, Larissa Sabo. "CARACTERIZAÇÃO DE EXTRATOS DE Connarus perrottetii var. angustifolius RADLK E AVALIAÇÃO DO COMPORTAMENTO ANTIOXIDANTE FRENTE A ESPÉCIES RADICALARES." Universidade Federal de Santa Maria, 2013. http://repositorio.ufsm.br/handle/1/6019.
This paper describes the development of methodology for capillary electrophoresis with UV detection for the determination of 14 polyphenolic antioxidants in extracts of Connarus perrottetii var. angustifolius Radlk, a native plant of the Amazon forest. The method using capillary zone electrophoresis (CZE) allows simultaneous determination of 3-acetyilcoumarine, resveratrol, 6-hydroxycoumarin, catechin, rutin, ferulic acid, quercitrin, kaempferol, fisetin, myricetin, quercetin, caffeic acid, gallic acid and 4 hydroxicinnamic acid in the optimized conditions: borate buffer 20 mmol L-1 (pH 9.2) as work electrolyte containing 15% methanol (v /v), -20 kV potential separation, temperature 25 °C; hydrodynamic injection gravity 20 cm for 60 s. The method was validated on parameters of linearity, limit of detection, quantification limit, precision and accuracy, and was used in the analysis of aqueous infusion and ethanol, butanol and ethyl acetate plant fractions. The method was capable of identifying the antioxidants present in samples with high selectivity and sensitivity. In infusion and in ethanol and butanol fractions was found the presence of catechin and rutin as major compounds, which makes up about 0.5% of the total mass of medicinal plant. The obtained dry extracts (ethanol and butanol) allowed the concentration of rutin and catechin around 20 times compared to the dry plant. In addition, tests were performed to measure the antioxidant activity of the extracts against DPPH radical, superoxide anion radical, hydroxyl and peroxyl. A sample of aqueous infusion of 10% showed the highest activity against most free radicals. It corroborates the results of characterization by capillary electrophoresis, where catechin and rutin were determined in relatively high concentrations in the aqueous infusion. But all treatments of the samples showed good antiradicalar behavior with the methodologies applied. Against DPPH, for example, the ethyl acetate fraction showed a potential of 94,43%. Against superoxide and hydroxyl radicals, the butanol fraction showed the best performance: 64,23% and 74,97%, respectively.
Este trabalho descreve o desenvolvimento de metodologia em eletroforese capilar com detecção UV para a determinação de 14 antioxidantes polifenólicos em extratos de Connarus perrottetii var. angustifolius Radlk, planta nativa da Amazônia brasileira. O método empregando eletroforese capilar de zona (CZE) permite a determinação simultânea de 3-acetilcumarina, resveratrol, 6-hidroxicumarina, catequina, rutina, ácido ferúlico, quercitrina, canferol, fisetina, miricetina, quercetina, ácido cafeico, ácido gálico e ácido 4-hidroxicinâmco nas condições otimizadas: eletrólito de trabalho tampão borato 20 mmol L-1 (pH 9,2) contendo metanol 15% (v/v), potencial de separação -20 Kv, temperatura 25 °C; injeção hidrodinâmica por gravidade em 20 cm durante 60 s. O método foi validado nos parâmetros de linearidade, limite de detecção, limite de quantificação, precisão e exatidão e foi aplicado na análise da infusão aquosa e frações etanólica, butanólica e acetato de etila da planta. O método foi capaz de identificar os antioxidantes presentes nas amostras com alta seletividade e sensibilidade. Na infusão e nas frações etanólica e butanólica foi encontrada a presença de catequina e rutina como compostos majoritários, os quais compõe cerca de 0,5% da massa total de planta medicinal. Os extratos secos obtidos (etanólico e butanólico) possibilitaram a concentração de rutina e catequina em torno de 20 vezes em relação à planta seca. Além disso, foram realizados testes para mensurar a atividade antioxidante dos extratos frente aos radicais DPPH, ânion radical superóxido, hidroxila e peroxila. A amostra de infusão aquosa a 10% foi a que apresentou maior atividade frente à maioria dos radicais livres. Esse resultado corrobora os resultados de caracterização por eletroforese capilar, onde catequina e rutina foram determinadas em concentrações relativamente altas na infusão aquosa. Porém, todos os tratamentos das amostras apresentaram bom comportamento anti-radicalar com as metodologias aplicadas. Frente ao radical DPPH, por exemplo, a fração acetato de etila demonstrou um potencial de 94,43%. Frente aos radicais superóxido e hidroxila, a fração butanólica apresentou o melhor desempenho: 64,23% e 74,97%, respectivamente.
Davidová, Jaroslava. "Diafragmový výboj v roztocích organických barviv z hlediska elektrolytického rozkladu." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2010. http://www.nusl.cz/ntk/nusl-216664.
Ducay, Rey Nann Mark Abaque. "Direct Detection of Aggregates in Turbid Colloidal Suspensions." Miami University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=miami1439434385.
Huang,Choung-Kun and 黃朝坤. "Analysis the Aquatic Humic Substances by the Absoption Column Method with UV/VIS detector, and the complexation between the Humic Substances and Metal Ions." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/33619175397803865252.
Collins, Julie Lynn. "Analysis of lichen phenolics as environmental stress indicators by liquid chromatography coupled to mass spectrometric and UV-VIS diode array detectors /." 2004.
Burdová, Vendula. "Voltametrické stanovení genotoxického 4-nitroindanu na rtuťových a stříbrných amalgámových elektrodách." Master's thesis, 2011. http://www.nusl.cz/ntk/nusl-297244.
Krejčová, Zuzana. "Voltametrické studium interakce genotoxického 2-nitrofluorenu s DNA na visící rtuťové kapkové elektrodě." Master's thesis, 2011. http://www.nusl.cz/ntk/nusl-297579.
Mniki, Nontle Catherine. "Protein phosphatase biosensor for the detection of cyanotoxins associated with algal bloom." 2013. http://hdl.handle.net/11394/3628.
The toxicity of microcystin is associated with the inhibition of serine/threonine protein phosphatases 1 and 2A, which can lead to hepatocyte necrosis and haemorrhage. Analysis of microcystin is most commonly carried out using reversed-phase high performance liquid chromatographic methods (HPLC) combined with ultra-violet (UV) detection .The ability of these techniques to identify unknown microcystin in environmental samples is also restricted by the lack of standard reference materials for the toxins. Highly specific recognition molecules such as antibodies and molecularly imprinted polymers (MIPs) have been employed in the pre-concentration of trace levels of microcystin from water and show great potential for the clean-up of complex samples for subsequent analysis. New biosensor technologies are also becoming available, with sufficient sensitivity and specificity to enable rapid ‗on-site‘ screening without the need for sample processing. In this work we constructed a Protein phosphatase biosensor for detection of microcystin-LR in aqueous medium, onto polyamic acid/graphene oxide (PAA: GO) composite electrochemically synthesised in our laboratory. The composites were synthesised at three different ratios i.e. 50:50, 80:20 and 20:80 to evaluate the effect of each component in the search to produce highly conductive mediator platforms. The electrochemistries of the three different composites were evaluated using CV and SWV to study interfacial kinetics of the materials as thin films at the glassy carbon electrode. The phosphatase biosensor parameters were evaluated using CV, SWV, EIS and Uv-vis spectroscopy. The affinity binding of the microcystin-LR to protein phosphatase 2A was investigated using electrochemical impedance spectroscopy which is a highly sensitive method for measuring interfacial kinetics of biosensor systems.
Farhat, Fatima. "Développement de méthodes analytiques de séparation des produits de digestion enzymatique des dérivés de cellulose." Thèse, 2009. http://hdl.handle.net/1866/3910.
Cellulose and its derivatives are used in a wide range of applications, including the pharmaceutical industry for the manufacturing of medicines as inactive additives. Various cellulosic derivatives such as carboxymethylcellulose (CMC) and hydroxyethylcellulose (HEC) are readily available for such use. The degree of polymerization and modification differs from one supplier to the other, according to the origin of the cellulose and its process of chemical modification, conferring on them different physico-chemical properties, such as viscosity and solubility. Our interest is to develop an analytical method that can distinguish between different sources of a given CMC or HEC product. The specific objective of this master’s study was to obtain a fingerprint of these complex biopolymers by developing an enzymatic digestion method to produce smaller oligosaccharides that could be separated by simple chromatographic methods. The digestion was studied as a function of various parameters, such as the composition of the hydrolysis solution, the pH, the temperature, the duration of digestion and the substrate/enzyme ratio. A cellulase enzyme from Trichoderma reesei ATCC 26921 was used for the partial digestion of our samples of cellulose. Since these oligosaccharides do not possess a chromophore or fluorophore, they can’t be detected either by absorbance or fluorescence. It was thus necessary to work out the labeling method for oligosaccharides using various agents, such as 8-aminopyrene-1,3,6-trisulfonic acid (APTS), 3-acetylamino-6-aminoacridine (AA-Ac) and phenylhydrazine (PHN). Finally, the use of capillary electrophoresis and high performance liquid chromatography allowed the separation of the enzymatic digestion products of the cellulose derivatives (CMC and HEC). For each of these analytical separation techniques, several parameters of the separation were studied.