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1

Mashamba, Mulalo Gift. "Process potentiometric sequential injection titrations." Pretoria : [s.n.], 2001. http://upetd.up.ac.za/thesis/available/etd-11212005-093416/.

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2

Santos, Marcos Alves dos. "Titulações potencio-condutimétricas simultâneas: método, programas para simulação e análise de dados e exemplos reais de aplicação." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/46/46133/tde-08112010-091604/.

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A despeito dos avanços instrumentais, as titulações continuam sendo largamente aplicadas em laboratórios de química analítica. Seu amplo uso está relacionado com a boa exatidão em aplicações bem estabelecidas e freqüente indicação como método de referência (p. ex., farmacopéias), equipamentos simples, comuns e de custo reduzido, consumo moderado de tempo e de reagentes. Entre as técnicas de titulação, destacam-se as potenciométricas (TP), empregadas universalmente para a quantificação de um ou mais componentes ácidos ou básicos em soluções aquosas ou não aquosas, possibilitando ainda determinar as constantes de dissociação de ácidos e de protonação de bases. Na análise de dados de TP são, via de regra, empregados os métodos clássicos (derivadas), porém, para sistemas compreendendo componentes multiprotonáveis, as inflexões das curvas de titulação deixam ser nítidas, especialmente em baixas concentrações. Nestas condições desfavoráveis, ainda assim podem-se obter resultados satisfatórios recorrendo a métodos de linearização das curvas ou analisando os dados por regressão não linear (RNL), facilmente implementáveis em computadores, hoje disseminados nos laboratórios. Outra técnica clássica para acompanhamento de titulações é a condutimétrica (TC), menos utilizada que a TP nos dias atuais, salvo para ácidos ou bases muito fracas, servindo para prover dados complementares em estudos de formação de complexos ou na caracterização de amostras ambientais. Tipicamente os pontos estequiométricos coincidem com a intersecção de segmentos de reta. Para amostras muito diluídas, com sistemas multipróticos ou com elevada concentração de eletrólitos em relação às espécies tituladas, a interpretação gráfica fica dificultada e a precisão decai. Pesquisas recentes mostraram que é possível aproveitar informações obtidas por TP para alimentar modelos de regressão não linear de TC e, assim, obter informações mais completas das amostras estudadas. No presente trabalho, avançou-se nesta linha criando programas computacionais para a análise simultânea de dados obtidos por TC e TP, empregando o método de RNL e minimizando os desvios (ou o quadrado dos desvios) dos dois conjuntos completos de dados para prover caracterização mais completa das amostras e melhoria na precisão dos resultados. Um programa de simulação de dados de TC e TP das mais diversas combinações e concentrações de sistemas ácido-base, com recursos para acrescentar erros aleatórios às variáveis simuladas, foi também desenvolvido. Permitiu verificar a validade e potencialidade do método da TPC-RNL e aperfeiçoar o programa de análise simultânea de dados. O programa de TPC-RNL foi aplicado inicialmente à re-avaliação de dados de titulações de água de chuva anteriormente coletadas e analisadas por outro colaborador do grupo. Como exemplo de aplicação original a amostras reais difíceis tanto para a TC como a TP isoladamente, determinou-se, por TPC, baixas concentrações de ácidos orgânicos de baixo peso molecular em amostras obtidas do produto de oxidação acelerada do biodiesel. Os resultados se mostraram compatíveis com os obtidos por outro pesquisador que recorreu à eletroforese capilar, sendo que o pH, a condutividade e a força iônica das amostras também foi reproduzida pelo programa Peak Master alimentado com as concentrações ajustadas por RNL
Despite all the advances in instrumental techniques, titrations are still widely applied in analytical chemistry laboratories. Its widespread use is associated with good accuracy, well established applications, simple, readily available and low cost equipment, moderate consumption of time and reagents and frequent indication as a reference method (eg., Pharmacopoeias). Potentiometric titrations (PT) outstands among other techniques, being universally used for the quantification of one or more basic or acidic components in aqueous or non aqueous samples and enabling further determination of the dissociation constants of acids and bases. Data analysis of PT with the glass electrode is typically done by finding the inflections of the curves with help of simple derivatives. However, PT curves of systems with multiprotonable components, specially at very low concentrations, fail to show sharp inflections. Under such unfavorable conditions, satisfactory results can still be obtained by using curve linearization methods or nonlinear regression (NLR) methods, now at the reach of every laboratory computer. Another classic technique for following titrations is conductivity (CT), less used routinely than PT nowadays except for very weak acids or bases, but still valuable as a complementary technique in equilibrium studies of complex formation or for the characterization of environmental samples. The stoichiometric points of simple CTs are found at the intersection of line segments. For very dilute samples or for multiprotic systems or with high concentrations of electrolytes compared to the species to be titrated, the graphical interpretation becomes difficult and the accuracy declines. Recent research has shown that it is possible to harness information obtained by PT to render non-linear regression models of CT solvable, thus extracting more complete information of the samples. This dissertation is devoted to the development and evaluation of software for the simultaneous analysis of data from CT and PT gathered together in the laboratory or by simulation, using the method of NLR with minimization of the weighted deviations (or their squares) of the two full data sets to provide more complete characterization of the samples and to improve the precision of the results. A simulation program for generating CT and PT curves for freely combined acid-base systems over a wide concentration range, with features to add random errors to the simulated variables was also developed. The simulator was used to evaluate the validity and potentiality of the PCTNLR method and improve the software of simultaneous data analysis. The program of PCT-NLR was applied firstly to the re-evaluation of data from titrations of rainwater collected and analyzed previously by another contributor to the group. As an original application example to real samples that are difficult for CT or PT separately, low concentrations of organic acids of low molecular weight were determined by PCT-NLR in samples from accelerated biodiesel oxidation tests. The results were consistent with those obtained by another researcher who used the capillary electrophoresis. The pH, ionic strength and conductivity of the samples were also reproduced by the program Peak Master using concentrations adjusted by NLR
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3

Sundman, Ola. "Cation adsorption properties of substituted kraft fibres : an experimental and thermodynamic modelling study." Doctoral thesis, Umeå universitet, Kemi, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1891.

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Acid/base and metal ion adsorption properties have been investigated for a range of chemically modified bleached Kraft fibre materials (pulps). The studies were performed via potentiometric titrations, Flame Atomic Absorbtion (and Emission) Spectroscopy, Inductively Coupled Plasma Optical Emission Spectroscopy and Extended X-ray Absorbtion Fine Structure measurements. As a result of a chemical modification procedure, the total concentration of acidic carboxylate groups in the fibre materials ranged between 43 and 590 μmol/g. The preferable surface potential model for modelling the ionic strength dependent acid/base properties of fibre materials with low charge densities, i.e. unmodified fully bleached Kraft fibre materials, was found to be the Basic Stern Model. For fibre materials with high total charge, ≳100 μmol/g, this model resulted in poor fits to data, and for such materials a number of Constant Capacitance Models, one at each ionic strength, must be recommended. With respect to metal ion adsorption, the results have indicated that the unspecific Donnan theory could correctly model the simultaneous adsorption of several metal ions, i.e. K+, Na+, Mg2+, Ca2+ and Cu2+, provided that the salt concentration in the fibre suspension is low. In suspensions of high salt concentration it was, however, found that this very same model strongly underestimated the adsorption of Ca2+ and Cu2+. Here, the Donnan model had to be complemented by specific ion exchange equilibria. These results were corroborated by spectroscopic evidence of specific interactions between Cu2+-ions and fibres. The spectroscopic indication of a complex formed between two fibre surface carboxylate groups and one Cu2+-ion, agree with the specific ion exchange model. It was therefore concluded that specific metal ionfibre interactions cannot be neglected, especially at high salt concentrations. The interactions occurring between the polycation GaO4Al12(OH)24(H2O)127+ and fibre materials were studied by both adsorption and spectroscopic measurements. These indicate that GaO4Al12(OH)24(H2O)127+ is surprisingly stable in fibre suspensions and that intact GaO4Al12(OH)24(H2O)127+- ions are strongly adsorbed onto the fibres. Also for this ion, specific interactions has to be considered, since the strong adsorption registered was too strong to be explained by Donnan equilibria. In the thesis, the stochiometric composition and an equilibrium constant characterising these interactions is presented.
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4

Kos, Nadja [Verfasser]. "Auswertungsmöglichkeiten und Optimierung potentiometrisch und photometrisch indizierter Titrationen / Nadja Kos." Berlin : Freie Universität Berlin, 2010. http://d-nb.info/1024743829/34.

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5

Gonçalves, Gabriela Soldi. "Atributos da validação do método analítico para quantificação da biotina empregando a técnica potenciométrica /." Araraquara : [s.n.], 2010. http://hdl.handle.net/11449/86497.

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Orientador: José Paschoal Batistuti
Banca: Fernando Luis Fertonani
Banca: Valeria Monterio da Silva Eleutério
Resumo: O presente trabalho consiste no desenvolvimento de um método analítico para determinação de biotina, utilizando-se a potenciometria indireta. O objetivo é apresentar a validação de método analítico como um processo que estime a eficiência do método proposto na rotina do laboratório para garantia da qualidade total. É um método que envolve equipamento simples e pouco dispendioso como o potenciômetro, que possibilita medir com precisão o valor da concentração de biotina. O doseamento quantitativo de biotina baseia-se no estudo das reações oscilantes do analito perante as análises da titulação indireta utilizando potenciômetro automático. A concentração de biotina foi determinada com massa adicionada conhecida numa matriz que simula uma cápsula, contendo aerosil (1%), estearato de magnésio (1%), celulose microcristalina (20%), amido (40%) e lactose q.s.p. Os resultados mostraram um valor médio de biotina (massa adicionada de aproximadamente 25 mg) determinada de 99,4% com desvio-padrão de 0,0345. As condições experimentais como temperatura, vidraria e concentração dos reagentes foram otimizadas. Os parâmetros investigados no processo de validação para demonstrar o desempenho do método foram: especificidade, linearidade, intervalo, precisão tanto repetitividade, quanto intermediária, exatidão e robustez. O tratamento estatístico dos dados da validação do método analítico envolveu a determinação da média, do desvio padrão e do coeficiente de variação. Para obtenção da curva de calibração se fez necessária a determinação da equação da reta, regressão linear e coeficiente de correlação linear. Este método apresenta grande aplicabilidade em soluções turvas, fluorescentes, opacas ou coradas, ou quando não existem, ou não podem aplicar-se indicadores visuais apropriados. Há possibilidade de determinação... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The present work shows the development of an analytical method for the determination of biotin by using indirect potentiometry. The main goal is to present the validation of analytical methods as a process to estimate the efficiency of the proposed methodology in the laboratory routine for the guaranty of total quality. This method involves simple and low cost devices as the potentiometer, which allows the precise measurement of biotin concentration. The quantitative dosing of biotin is based on the study of the oscillating chemical reactions with the analyte by performing the analysis of the indirect titration with an automatic potentiometer. Biotin concentration was determined by adding a known mass to a matrix that simulates a capsule containing aerosol (1%), estearato de magnésio (1%), celulose microcristalina (20%), amido (40%) e lactose q.s.p. The results showed an average value for the determination of biotin (added mass was ca. 25 mg) of 99.4% with a standard deviation of 0.0345. The experimental conditions as temperature, glassware, and concentration of the chemicals were optimized. The investigated parameters of the validation procedure to demonstrate the performance of the method were: specificity, linearity, interval, precision (repeatability and intermediate), exactness and robustness. The statistical treatment of the data for the validation of the analytical method involved the determination of the average value, standard deviation, and the variation coefficient. In order to obtain the calibration curve, the line's equation, the linear regression and the coefficient of linear correlation were determined. This method shows great applicability for turbid, fluorescent, opaque or color solutions, or if an appropriate visual indicator is not available or cannot be applied. The method also shows the possibility for the determination of a sequence of equivalence... (Complete abstract click electronic access below)
Mestre
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6

Felix, Olivia. "Etude thermodynamique de la sorption de l'uranyle sur la monazite et la magnétite." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00737326.

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Les phénomènes d'adsorption interviennent dans les processus géochimiques gouvernant ainsi le transport des contaminants. Par ailleurs, les variations de température sont susceptibles d'influencer significativement leur comportement vis-à-vis de la surface des minéraux. Aussi, l'influence de la température sur la sorption doit être étudiée afin de mieux appréhender le devenir des éléments dans l'environnement. Dans cette optique, l'interaction entre un ion modèle, l'uranyle et deux minéraux a été étudiée. Dans un premier temps, un composé méthodologique, la monazite, a été choisi afin de déterminer la démarche à suivre pour étudier l'influence de la température sur la sorption de l'uranyle dans trois milieux plus ou moins complexants. Puis, des tests préliminaires ont été réalisés pour étudier la sorption de l'uranyle sur un composé d'intérêt industriel, la magnétite, en appliquant la démarche mise en place. Le solide a d'abord été caractérisé d'un point de vue massif puis les caractéristiques acido-basiques de sa mise en suspension dans les trois électrolytes (NaClO4, NaNO3 et Na2SO4) ont été étudiées en fonction de la température. Les constantes d'équilibre associées aux réactions de déprotonation des sites de surface ont été déterminées entre 25°C et 95°C par modélisation de courbes de titrages potentiométriques. Les simulations ont été effectuées en limitant au maximum le nombre de degrés de liberté du système. Le modèle 1-pK a donc été préféré au modèle 2-pK en raison du nombre de paramètres ajustables plus limité dans ce modèle. Des contraintes expérimentales telles que le pH de point de charge nulle ou les enthalpies déterminées par mesure directe des chaleurs associées par microcalorimétrie de mélange ont été imposées pour déterminer les constantes d'équilibre acido-basiques. La sorption de l'uranyle en fonction du pH sur le même intervalle de température a été étudiée en alliant l'acquisition de données macroscopiques telles que les sauts de sorption et la spéciation en solution à une étude structurale menée par analyse par spectrofluorimétrie laser permettant l'identification des espèces sorbées. La simulation des sauts de sorption permettant d'accéder aux constantes associées aux réactions de sorption a été réalisée en imposant les caractéristiques acido-basiques préalablement déterminées. Des mesures directes, par microcalorimétrie de mélange, des chaleurs mises en jeu lors de la sorption de l'uranyle ont permis de tester la validité de la loi de Van't Hoff sur ce phénomène. La même démarche a été suivie pour étudier l'influence de la température sur la sorption de l'uranyle sur la magnétite en milieu NaClO4 et NaNO3. Cependant, l'étude structurale par spectrofluorimétrie laser n'a pu être réalisée en raison de la couloration noire de la magnétite.
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7

Gonçalves, Gabriela Soldi [UNESP]. "Atributos da validação do método analítico para quantificação da biotina empregando a técnica potenciométrica." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/86497.

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Made available in DSpace on 2014-06-11T19:22:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-12-20Bitstream added on 2014-06-13T20:28:32Z : No. of bitstreams: 1 goncalves_gs_me_arafcf.pdf: 376750 bytes, checksum: d261fb301fa1b4c966236fbf2eb5c9d0 (MD5)
Universidade Estadual Paulista (UNESP)
O presente trabalho consiste no desenvolvimento de um método analítico para determinação de biotina, utilizando-se a potenciometria indireta. O objetivo é apresentar a validação de método analítico como um processo que estime a eficiência do método proposto na rotina do laboratório para garantia da qualidade total. É um método que envolve equipamento simples e pouco dispendioso como o potenciômetro, que possibilita medir com precisão o valor da concentração de biotina. O doseamento quantitativo de biotina baseia-se no estudo das reações oscilantes do analito perante as análises da titulação indireta utilizando potenciômetro automático. A concentração de biotina foi determinada com massa adicionada conhecida numa matriz que simula uma cápsula, contendo aerosil (1%), estearato de magnésio (1%), celulose microcristalina (20%), amido (40%) e lactose q.s.p. Os resultados mostraram um valor médio de biotina (massa adicionada de aproximadamente 25 mg) determinada de 99,4% com desvio-padrão de 0,0345. As condições experimentais como temperatura, vidraria e concentração dos reagentes foram otimizadas. Os parâmetros investigados no processo de validação para demonstrar o desempenho do método foram: especificidade, linearidade, intervalo, precisão tanto repetitividade, quanto intermediária, exatidão e robustez. O tratamento estatístico dos dados da validação do método analítico envolveu a determinação da média, do desvio padrão e do coeficiente de variação. Para obtenção da curva de calibração se fez necessária a determinação da equação da reta, regressão linear e coeficiente de correlação linear. Este método apresenta grande aplicabilidade em soluções turvas, fluorescentes, opacas ou coradas, ou quando não existem, ou não podem aplicar-se indicadores visuais apropriados. Há possibilidade de determinação...
The present work shows the development of an analytical method for the determination of biotin by using indirect potentiometry. The main goal is to present the validation of analytical methods as a process to estimate the efficiency of the proposed methodology in the laboratory routine for the guaranty of total quality. This method involves simple and low cost devices as the potentiometer, which allows the precise measurement of biotin concentration. The quantitative dosing of biotin is based on the study of the oscillating chemical reactions with the analyte by performing the analysis of the indirect titration with an automatic potentiometer. Biotin concentration was determined by adding a known mass to a matrix that simulates a capsule containing aerosol (1%), estearato de magnésio (1%), celulose microcristalina (20%), amido (40%) e lactose q.s.p. The results showed an average value for the determination of biotin (added mass was ca. 25 mg) of 99.4% with a standard deviation of 0.0345. The experimental conditions as temperature, glassware, and concentration of the chemicals were optimized. The investigated parameters of the validation procedure to demonstrate the performance of the method were: specificity, linearity, interval, precision (repeatability and intermediate), exactness and robustness. The statistical treatment of the data for the validation of the analytical method involved the determination of the average value, standard deviation, and the variation coefficient. In order to obtain the calibration curve, the line´s equation, the linear regression and the coefficient of linear correlation were determined. This method shows great applicability for turbid, fluorescent, opaque or color solutions, or if an appropriate visual indicator is not available or cannot be applied. The method also shows the possibility for the determination of a sequence of equivalence... (Complete abstract click electronic access below)
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8

Elmroth, Edvin. "Method development for quality control of the primary explosive, Potassium 4,6-Dinitrobenzofuroxan (KDNBF)." Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-84289.

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“Green” explosives are an important sub-family of explosives due to the banning of explosives based on heavy metals, such as lead azide and lead styphnate, according to the REACH list. A substitute to lead azide is potassium 4,6-dinitrobenzofuroxane (KDNBF) which is an alternative “green” explosive. Hence there is an upcoming need for analytical and quality control protocols for KDNBF. In this report is HPLC-UV/VIS, GC-FID and potentiometric titration evaluated for their suitability as methods for testing of KDNBF. The results implies that KDNBF can be analyzed by GC-FID, when dissolved in DMSO and caffeine is used as internal standard. To analyze KDNBF by HPLC-UV/VIS was isocratic mode used together with a porous graphitic carbon (PGC) (Hypercarb ®) column. However, degradation of the analyte was severe and quantitative results were not obtained. Potentiometric titration indicated that KDNBF equilibrate with four hydrogen ions during titration, instead of the one to one ratio with potassium and hydrogen ion, as in previously proposed theory. Despite this and with careful titration is potentiometric titration and GC-FID analysis combined suitable as a quality control protocol for KDNBF.
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9

Braz, Ana KÃtia de Sousa. "CaracterizaÃÃo de Ãguas produzidas provenientes de plataformas marÃtimas da bacia do CearÃ." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=13721.

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Nesse trabalho, foram caracterizadas 238 amostras de Ãgua produzida, oriundos de quatro campos de produÃÃo diferentes, todos provenientes de campos marÃtimos da bacia do CearÃ, denominados campo de produÃÃo A, campo de produÃÃo B, campo de produÃÃo C e campo de produÃÃo D. Foram determinados, os Ãnions (Acetato, Cloreto, Formiato, Sulfato) utilizando-se a cromatografia de Ãons; exceto, para o Ãnion Bicarbonato que foi determinado utilizando-se a titulaÃÃo potenciomÃtrica. E, os cÃtions (BÃrio, CÃlcio, EstrÃncio, Ferro Total, LÃtio, MagnÃsio, PotÃssio, SÃdio) utilizando-se a espectrometria de emissÃo Ãptica com plasma acoplado indutivamente. Para tratamento estatÃstico, utilizou-se como ferramenta, a PCA (anÃlise de componentes principais) e a HCA (anÃlise de agrupamento hierÃrquico). Na avaliaÃÃo da qualidade dos dados, utilizou-se o balanÃo iÃnico. Para visualizaÃÃo dos resultados, utilizou-se o grÃfico boxplot, onde se pode observar que o campo de produÃÃo A, seguido do campo de produÃÃo B, possuem tendÃncia à corrosÃo e à incrustaÃÃo, respectivamente. Como tambÃm, o campo de produÃÃo D que apresentou propensÃo à corrosÃo, mas em menor escala. Vale salientar a necessidade de uma caracterizaÃÃo individual das amostras, para conhecimento dos principais constituintes existentes. Pois, esses constituintes podem acarretar elevados custos na manutenÃÃo do processo produtivo da indÃstria petrolÃfera; devido, a corrosÃo do tipo pite, que promove a modificaÃÃo da aparÃncia e estrutura dos aÃos inoxidÃveis, muito utilizados na indÃstria petrolÃfera; e, as incrustaÃÃes, que tendem a se depositar nas paredes das tubulaÃÃes, que podem causar problemas como perda de pressÃo, diminuiÃÃo do escoamento da produÃÃo e aumento no consumo de energia.
In this study, we characterized 238 samples of water produced from four different production fields, all from offshore fields of the Cearà basin, called The field of production, production field B, C production and field production field D. were determined anions (acetate, chloride, formate, sulfate) using ion chromatography; except for the bicarbonate anion was determined using potentiometric titration. And, cations (Barium, Calcium, Strontium, total iron, lithium, magnesium, potassium, sodium) using the optical emission spectrometry with inductively coupled plasma. For statistical analysis, we used as a tool, the PCA (principal component analysis) and HCA (hierarchical cluster analysis). In evaluating the quality of the data, we used the ionic balance. To visualize the results, we used the box plot graph where one can observe that the production field, followed by the production field B, are prone to corrosion and fouling, respectively. As well, the D production field that showed propensity to corrosion, but on a smaller scale. It is worth stressing the need for individual characterization of the samples, to knowledge of the main existing constituents. For these constituents can incur high costs in maintaining the productive process of the oil industry; due to corrosion pitting type, which promotes change the look and structure of stainless steel, widely used in the oil industry; and incrustations which tend to deposit on the walls of pipes, which may cause problems such as pressure loss, decreased production flow and an increase in power consumption.
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Langer, Matthias. "Protonierungs-, Komplexbildungs- und Verteilungseigenschaften von tripodalen Azaliganden." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2006. http://nbn-resolving.de/urn:nbn:de:swb:14-1144746562988-21053.

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Ziel der Untersuchungen war die Charakterisierung der Protonierungs-, Komplexbildungs- und Verteilungseigenschaften von tripodalen Azaliganden unter Anwendung thermodynamischer und spektroskopischer Verfahren. Im Vordergrund stand dabei der Einfluß des Lösungsmittels auf die zugrundeliegenden Gleichgewichte. Ausgehend von dem Aminopodanden Tris(2-aminoethylamin) (tren) wurden für eine Reihe abgeleiteter Verbindungen mit unterschiedlichen Stickstoffdonorfunktionen und Substituenten Faktoren untersucht, welche die beteiligten Gleichgewichte beeinflussen. Das Protonierungsverhalten der Polyaminverbindungen ist im starken Maße von elektrostatischen, elektronischen und Solvenseinflüssen abhängig, welche durch den Abstand der benachbarten Aminfunktionen, die Substitution am Aminstickstoffatom und die sterischen Eigenschaften der Substituenten bestimmt werden. Faktoren, welche die Solvatation der Aminfunktionen verringern, führen zu einer Verringerung der Protonierungskonstanten. Zudem beeinflussen die Zusammensetzung der verwendeten Methanol-Wasser-Gemische sowie das verwendete Leitsalz die Protonierungskonstanten z.T. deutlich. Die Komplexbildung der untersuchten Azapodanden mit Ag+ in Methanol zeigt Unterschiede, welche hauptsächlich auf die unterschiedliche Basizität von Imin- bzw. Aminstickstoffatomen sowie Substituenteneffekte zurückzuführen sind. Von sterisch aufwendigen Substituenten an den Donorfunktionen der Podandarme können zudem destabilisiernde Effekte infolge der Beeinflussung der Koordinationsgeometrie von Ag+ ausgehen. Heteroditope Tetraazacryptanden zeigen gegenüber abgeleiteten offenkettigen Podanden erhöhte Stabilitätskonstanten, wobei auch die Verknüpfungsposition der tripodalen Einheiten am Phenylspacer und die Bindung von Wasser im Käfighohlraum eine Rolle spielen. Lösungsmittelpolarität und Gegenion haben einen deutlichen Einfluß auf die Komplexbildung mit Ag+. Der Schwerpunkt von Untersuchungen an Zweiphasensystemenen wäßrig-organisch lag auf dem Übergang von Wasser in die organische Phase unter dem Einfluß von extrahierten Spezies bei der Kationen- und Anionenextraktion. Mit der Verteilung von Liganden und Kationen- bzw. Anionenkomplexen lassen sich Änderungen des Wassersättigungsgehaltes in der niedrigpolaren organischen Phase registrieren, die mit der unterschiedlichen Hydratation der Spezies korrelieren. Qualitativ wurde die Hydratation von Azapodanden mittels IR- und 1H-NMR-Spektroskopie nachgewiesen, wobei auch Hinweise auf bestimmte, die Hydratation verringernde Faktoren, wie intramolekulare Wasserstoffbrücken, erhalten wurden. Quantitativ konnten mittels Karl-Fischer-Titration und Verteilungsmessungen Hydratationszahlen für ausgewählte Ligansysteme bestimmt werden. Extrahierte Komplexe der Verbindungen mit Ag+, Co2+, Ni2+ und Zn2+ zeigen eine gegenüber den freien Komplexbildnern veränderte Hydratation. Bei Ag+ kann in allen Fällen von einer deutlichen Verringerung der Hydratationszahlen ausgegangen werden. Für die zweifachgeladenen Kationen konnte kein klarer Nachweis erbracht werden. Es ergeben sich aber Hinweise, wonach zum Teil keine Verringerung auftritt, was auf eine zusätzliche Koordinationsstellen von Wasser am Kation hinweist. Bei der Iodidextraktion treten bei gleichzeitiger pH-Abhängigkeit mehrere Komplexspezies auf, was die Bestimmung von Hydratationszahlen erschwert. Als hilfreich erwies sich die Simulation für verschiedene mögliche Zusammensetzungen. Dabei stellte sich heraus, daß der 1:1-Komplex des untersuchten monoprotonierten Aminopodanden in Chloroform wahrscheinlich stärker hydratisiert ist als der freie Ligand, während die entsprechende 1:2-Spezies (Ligand:Iodid) eine ähnliche oder schwächere Hydratation aufweist als der Ligand.
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11

Sabuncu, Sinan. "Investigation of enzymes from the respiratory chain by using electrochemical and spectroscopic techniques." Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAF017/document.

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Le présent travail porte sur l’étude de deux protéines de la famille des oxydases à hème-fer par des techniques de spectroscopie et d’électrochimie. Le premier chapitre décrit l’étude du cytochrome bo3 oxydase issue d’E. coli. Nous nous sommes intéressés à l’étude des interactions enzyme-quinone par l’utilisation de quinones avec des longueurs chaines isoprenyl différentes. Notre but est de mieux comprendre le rôle de la longueur de la chaine des quinones sur l’activité catalytique de l’enzyme et sur les propriétés redox des cofacteurs à hème. Dans l’étape suivante, on a étudié les résidus impliqués dans le site de liaison des quinones (haute affinité, QH). Plusieurs mutations de ces résidus sont étudiées pour mieux comprendre l’importance de chacun des résidus dans cette liaison. Dans la dernière partie de ce premier chapitre, la spectroscopie SEIRAS «spectroscopie d’absorption infrarouge exaltée de surface» est introduite comme une technique alternative pour l’étude des protéines membranaires. Dans le second chapitre, la protéine membranaire cNOR issue de P. denitrificans est étudiée. Nous nous sommes focalisés sur l’effet de différents environnements (pH, présence de protéo-liposomes) sur la stabilité de la cNOR. Pour ce faire, trois valeurs de pH (6.5, 7.5 et 8.5) sont choisies et quelques échantillons de cNOR sont reconstitués dans des protéo-liposomes. Enfin, le donneur de proton terminal (au centre binucléaire) dans la protéine cNOR était étudié. De plus, nous avons étudié les ligands des ions Ca2+ puisqu’il est proposé que le donneur de proton est situé proche de cette région
This thesis is focused on the study of two members of the heme-copper oxidase family by using spectroscopic and electrochemical techniques. In the first chapter cytochrome bo3 oxidase from E. coli was studied. We focused on the quinone-enzyme interactions by using quinones with different isoprenyl chains. Our aim was to better understand the role of isoprenyl chain on the catalytic activity of the enzyme and the redox properties of the heme cofactors. In the next step we studied the residues that are suggested to be in the high-affinity (QH) quinone binding site. Several site-directed mutants of these residues were investigated in order to better understand the position of QH binding site and the importance of each residue. In the last part of this chapter surface-enhanced infrared absorption spectroscopy (SEIRAS) was introduced as an alternative technique to study the membrane proteins. In the second chapter cytochrome c dependent nitric oxide reducates (cNOR) from P. denitrificans was studied. We focused on the effect of different environment (pH, proteoliposomes) on the stability of cNOR. For that purpose three pH values (6.5, 7.5 and 8.5) was selected and some of the cNOR samples were reconstituted in liposomes. Finally, the terminal proton donor (to the binuclear center) in cNOR was investigated. We studied the ligands of the Ca2+ site in cNOR since it was suggested that the proton donor may be close to this area
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12

Langer, Matthias. "Protonierungs-, Komplexbildungs- und Verteilungseigenschaften von tripodalen Azaliganden." Doctoral thesis, Technische Universität Dresden, 2005. https://tud.qucosa.de/id/qucosa%3A24687.

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Ziel der Untersuchungen war die Charakterisierung der Protonierungs-, Komplexbildungs- und Verteilungseigenschaften von tripodalen Azaliganden unter Anwendung thermodynamischer und spektroskopischer Verfahren. Im Vordergrund stand dabei der Einfluß des Lösungsmittels auf die zugrundeliegenden Gleichgewichte. Ausgehend von dem Aminopodanden Tris(2-aminoethylamin) (tren) wurden für eine Reihe abgeleiteter Verbindungen mit unterschiedlichen Stickstoffdonorfunktionen und Substituenten Faktoren untersucht, welche die beteiligten Gleichgewichte beeinflussen. Das Protonierungsverhalten der Polyaminverbindungen ist im starken Maße von elektrostatischen, elektronischen und Solvenseinflüssen abhängig, welche durch den Abstand der benachbarten Aminfunktionen, die Substitution am Aminstickstoffatom und die sterischen Eigenschaften der Substituenten bestimmt werden. Faktoren, welche die Solvatation der Aminfunktionen verringern, führen zu einer Verringerung der Protonierungskonstanten. Zudem beeinflussen die Zusammensetzung der verwendeten Methanol-Wasser-Gemische sowie das verwendete Leitsalz die Protonierungskonstanten z.T. deutlich. Die Komplexbildung der untersuchten Azapodanden mit Ag+ in Methanol zeigt Unterschiede, welche hauptsächlich auf die unterschiedliche Basizität von Imin- bzw. Aminstickstoffatomen sowie Substituenteneffekte zurückzuführen sind. Von sterisch aufwendigen Substituenten an den Donorfunktionen der Podandarme können zudem destabilisiernde Effekte infolge der Beeinflussung der Koordinationsgeometrie von Ag+ ausgehen. Heteroditope Tetraazacryptanden zeigen gegenüber abgeleiteten offenkettigen Podanden erhöhte Stabilitätskonstanten, wobei auch die Verknüpfungsposition der tripodalen Einheiten am Phenylspacer und die Bindung von Wasser im Käfighohlraum eine Rolle spielen. Lösungsmittelpolarität und Gegenion haben einen deutlichen Einfluß auf die Komplexbildung mit Ag+. Der Schwerpunkt von Untersuchungen an Zweiphasensystemenen wäßrig-organisch lag auf dem Übergang von Wasser in die organische Phase unter dem Einfluß von extrahierten Spezies bei der Kationen- und Anionenextraktion. Mit der Verteilung von Liganden und Kationen- bzw. Anionenkomplexen lassen sich Änderungen des Wassersättigungsgehaltes in der niedrigpolaren organischen Phase registrieren, die mit der unterschiedlichen Hydratation der Spezies korrelieren. Qualitativ wurde die Hydratation von Azapodanden mittels IR- und 1H-NMR-Spektroskopie nachgewiesen, wobei auch Hinweise auf bestimmte, die Hydratation verringernde Faktoren, wie intramolekulare Wasserstoffbrücken, erhalten wurden. Quantitativ konnten mittels Karl-Fischer-Titration und Verteilungsmessungen Hydratationszahlen für ausgewählte Ligansysteme bestimmt werden. Extrahierte Komplexe der Verbindungen mit Ag+, Co2+, Ni2+ und Zn2+ zeigen eine gegenüber den freien Komplexbildnern veränderte Hydratation. Bei Ag+ kann in allen Fällen von einer deutlichen Verringerung der Hydratationszahlen ausgegangen werden. Für die zweifachgeladenen Kationen konnte kein klarer Nachweis erbracht werden. Es ergeben sich aber Hinweise, wonach zum Teil keine Verringerung auftritt, was auf eine zusätzliche Koordinationsstellen von Wasser am Kation hinweist. Bei der Iodidextraktion treten bei gleichzeitiger pH-Abhängigkeit mehrere Komplexspezies auf, was die Bestimmung von Hydratationszahlen erschwert. Als hilfreich erwies sich die Simulation für verschiedene mögliche Zusammensetzungen. Dabei stellte sich heraus, daß der 1:1-Komplex des untersuchten monoprotonierten Aminopodanden in Chloroform wahrscheinlich stärker hydratisiert ist als der freie Ligand, während die entsprechende 1:2-Spezies (Ligand:Iodid) eine ähnliche oder schwächere Hydratation aufweist als der Ligand.
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13

Jonsson, Caroline. "Modeling of glyphosate and metal-glyphosate speciation in solution and at solution-mineral interfaces." Doctoral thesis, Umeå : Department of Chemistry, Umeå Univ, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1074.

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14

Mottot, Yves. "Propriétés chimiques et électrochimiques des chlorures de lanthanides cérides en milieux chlorures fondus : stabilité thermodynamique des alliages LA-NI et ND-FE à haute température." Paris 6, 1986. http://www.theses.fr/1986PA066127.

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Etude thermodynamique et cinétique de la réduction électrolytique de terres rares cériques, réalisée au sein de l'eutectique fondu LICL-KCL. Comportement singulier du néodyme étudié dans l'eutectique BACL::(2)-KCL jusqu'à 1300k; on montre que la stabilité de ND(II) croit avec la température. Etude des alliages entre les métaux des terres rares et les métaux de transition de composition générale LNM::(X), dont les propriétés thermodynamiques ont été déterminées par mesure de la F. E. M. De la pile LN/LNCL::(3), LICL+KCL/LNM::(X); application aux alliages LA-NI ET ND-FE entre 700 et 800K.
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15

Mashamba, Mulalo Gift. "Process potentiometric sequential injection titrations." Diss., 2002. http://hdl.handle.net/2263/29637.

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Interest in the automation of titration arise from the fact that many acid-base titrations in the process industries rely on manual titration which is time consuming. Miniaturization of these titration processes becomes attractive because of the reduced reagent consumption. These industries must produce higher quality products economically and in a friendly environment. Due to its ease of automation, ability to handle concentrated solutions and simplicity, the application of sequential injection titration is an ideal tool in process effluent streams, food industries, beverage industries and production plants. The sequential injection titration system was optimised with respect to all instrumental parameters of the system and applied for acid-base titrations. The results obtained showed high reliability and reproducibility. The system is fully computerised, inexpensive and suitable for on-line monitoring.
Dissertation (MSc (Chemistry))--University of Pretoria, 2006.
Chemistry
unrestricted
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16

Norman, Sarah Elizabeth. "Chemical process analysis: chemometrics; instrument control; applications in equilibrium and kinetic investigations." Thesis, 2008. http://hdl.handle.net/1959.13/802346.

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Research Doctorate - Doctor of Philosophy (PhD)
This work presents the development and application of modern data acquisition and analysis techniques for the investigations of equilibrium and kinetic reactions. The analytical technique is known as second order global analysis and a background of this relatively novel approach has been given. The theory behind and characteristics of the computer programs developed analysis as part of this research are described in Chapter Two along with descriptions of the instrumentation and programs developed for the acquisition of both potentiometric and spectrophotometric data. Applications of the developed programs include a potentiometric and spectrophotometric study of the protonation and stability equilibria of a series of polydentate N-donor ligands, as detailed in Chapter Three. The combination of potentiometric and spectrophotometric analysis has been shown to be a powerful analytical tool. Spectrophotometric titrations were also combined with fast stop-flow experiments in order to elucidate the complex reaction mechanisms associated with helicating ligands. The helication of the ligand ‘PepdaH₂’ with copper(II) and nickel(II) is examined in Chapter Four, along with discussions concerning the ability to induce chirality in the helicates from the addition of a chiral counter ion. Investigations into chirality were further continued in Chapter Five where the stereoselectivity of a benzimidazole-based ligand was investigated with circular dichroism titrations. The synthesis and characterisation of the benzimidazole-based ligands are provided, including a study of the ability of the ligands to form higher order complexes as investigated using electrospray mass spectroscopy. Chapter Six provides an in-depth discussion concerning the use of combined glass hydrogen selective electrodes for the determination of equilibrium constants, as this was a major focus of this research. Different calibration techniques are discussed and a description of the internal calibration technique developed is provided along with examples of the advantages of performing internal calibration of the electrode.
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17

Norman, Sarah Elizabeth. "Chemical process analysis: chemometrics; instrument control; applications in equilibrium and kinetic investigations." 2008. http://hdl.handle.net/1959.13/802346.

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Research Doctorate - Doctor of Philosophy (PhD)
This work presents the development and application of modern data acquisition and analysis techniques for the investigations of equilibrium and kinetic reactions. The analytical technique is known as second order global analysis and a background of this relatively novel approach has been given. The theory behind and characteristics of the computer programs developed analysis as part of this research are described in Chapter Two along with descriptions of the instrumentation and programs developed for the acquisition of both potentiometric and spectrophotometric data. Applications of the developed programs include a potentiometric and spectrophotometric study of the protonation and stability equilibria of a series of polydentate N-donor ligands, as detailed in Chapter Three. The combination of potentiometric and spectrophotometric analysis has been shown to be a powerful analytical tool. Spectrophotometric titrations were also combined with fast stop-flow experiments in order to elucidate the complex reaction mechanisms associated with helicating ligands. The helication of the ligand ‘PepdaH₂’ with copper(II) and nickel(II) is examined in Chapter Four, along with discussions concerning the ability to induce chirality in the helicates from the addition of a chiral counter ion. Investigations into chirality were further continued in Chapter Five where the stereoselectivity of a benzimidazole-based ligand was investigated with circular dichroism titrations. The synthesis and characterisation of the benzimidazole-based ligands are provided, including a study of the ability of the ligands to form higher order complexes as investigated using electrospray mass spectroscopy. Chapter Six provides an in-depth discussion concerning the use of combined glass hydrogen selective electrodes for the determination of equilibrium constants, as this was a major focus of this research. Different calibration techniques are discussed and a description of the internal calibration technique developed is provided along with examples of the advantages of performing internal calibration of the electrode.
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18

西尾, 卓広, and Takuhiro Nishio. "Monte Carlo simulation studies on potentiometric titration behavior of linear polyelectrolytes in aqueous solution." Thesis, 1997. http://hdl.handle.net/2237/15756.

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19

Palaniswamy, R., C. Wang, Michael K. C. Tam, and L. H. Gan. "Association Behavior of Poly(methacrylic acid)-block-Poly(methyl methacrylate) in Aqueous Medium: Potentiometric and Laser Light Scattering Studies." 2003. http://hdl.handle.net/1721.1/3775.

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Atom transfer radical polymerisation (ATRP) technique was used to synthesize poly(methacrylic acid-block-methyl methacrylate) (P(MAA₁₀₂-b-MMA₁₀)) copolymer in order to study the aggregation behavior in aqueous solution over the course of neutralization. A combination of static and dynamic light scattering (SLS, DLS) and potentiometric titration techniques were used to investigate the size and shape of the micelle at various degrees of neutralization. The hydrodynamic radius (Rh) determined from dynamic light scattering increases from ~26nm (for unneutralized) to ~42nm (for completely neutralized sample). Both potentiometric and laser light scattering studies indicate the formation of a core shell micelle. The weighted average molecular weights of the polymer and micelle are 1.18x10⁴ and 2.25 x 10⁵ g/mol respectively, which suggests that the aggregation number of the micelle is ~20.
Singapore-MIT Alliance (SMA)
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20

Yao, Jia, R. Palaniswamy, Michael K. C. Tam, and L. H. Gan. "Association Behavior of Poly (methyl methacrylate-b-methacrylic acid-b-methyl methacrylate) in Aqueous Medium." 2003. http://hdl.handle.net/1721.1/3925.

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ABA type tri-block amphiphilic polyelectrolyte consisting of poly(methyl methacrylate-block-methacrylic acid-block-methyl methacrylate) (P(MMA-b-MAA-b-MMA)) was synthesized by atom transfer radical polymerization technique (ATRP) and the self-assembly behavior of the polymers in aqueous solution was studied over the course of neutralization. Combination of potentiometric and conductometric titrations along with dynamic light scattering (DLS) techniques were used to investigate the size and shape of aggregates at various degrees of neutralization. The effect of hydrophobic-hydrophilic (MMA-MAA) ratio and polymer chain length on the aggregation behavior during neutralization was studied. P(MMA-b-MAA-b-MMA) with longer MMA segment self-assembles via the close association mechanism through stronger self-entanglement of MMA chains, whereas P(MMA-b-MAA-b-MMA) with shorter MMA chain self-assembles via the open association mechanism, as confirmed by transmission electron microscopy (TEM). Conductometric titration was used to determine the counterion condensation during the course of neutralization. When the charge density of micelle approaches a critical value as neutralization progresses, counterion condensation of Na+ ions on the polymer chains occurs. The effect of counterion condensation on the aggregation behavior during neutralization was elucidated.
Singapore-MIT Alliance (SMA)
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21

Pham, Duc-Truc. "Beta-cyclodextrin modification and host-guest complexation." 2008. http://hdl.handle.net/2440/57975.

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A series of five linked β-cyclodextrin (βCD) dimers N,N-bis(6 [superscript]A-deoxy-6[superscript]A-β-cyclodextrinyl)-succinamide, 66βCD₂su, N-((2[superscript]A S,3 [superscript]A S)-3 [superscript]A-deoxy-3 [superscript]A-β-cyclodextrinyl)-N’-(6 [superscript]A-deoxy-6 [superscript]A -β-cyclodextrinyl)-urea, 36βCD₂su, N,N-bis((2 [superscript]A S,3 [superscript]A S)-3 [superscript]A -deoxy-3 [superscript]A-β-cyclodextrinyl)-succinamide, 33βCD₂su, N,N-bis(6[superscript]A-deoxy-6[superscript]A-β-cyclodextrinyl)-urea, 66βCD₂ur, and N-((2 [superscript]A S,3 [superscript]A S)-3 [superscript]A-deoxy-3 [superscript]A-β-cyclodextrinyl)-N’-(6 [superscript]A -deoxy-6 [superscript]A -β-cyclodextrinyl)urea, 36βCD₂ur, has been prepared. The complexation of 6-(4’-(toluidinyl)naphthalene-2-sulphonate, TNS⁻, by βCD and the five linked βCD dimers was characterized by UV, fluorescence and 2D ¹H ROESY NMR spectroscopy. In aqueous phosphate buffer at pH 7.0, I = 0.10 mol dm⁻³ and 298.2 K, TNS⁻ forms host-guest complexes with βCD of stoichiometry βCD.TNS⁻ (K₁ = 3020 and 3320 dm³ mol⁻¹) and βCD₂.TNS⁻ (K₂ = 57 and 11 dm³ mol⁻¹) where the first and second values were determined in UV and fluorescence studies, respectively. For 66βCD₂su, 36βCD₂su, 33βCD₂su, 66βCD₂ur and 36βCD₂ur, the analogous K₁ = 16100, 10900, 10700, 55100 and 18300 dm³ mol⁻¹ and K₁ = 12500, 8700, 9600, 38000 and 9800 dm³ mol⁻¹(fluorimetric studies), respectively. ¹H 2D ROESY NMR studies provided evidence for variation of the mode of complexation of the TNS⁻ guest as the βCD host is changed. The factors affecting complexation are discussed. UV and ¹H NMR studies showed that 6-(4’-(t-butyl)-phenyl)naphthalene-2-sulphonate, BNS⁻, and its dimer, (BNS⁻)₂, form host-guest complexes with βCD of the stoichiometry βCD.BNS⁻ (K₁ = 5.54 × 10⁴ dm³ mol⁻¹ ) and βCD.BNS₂ ²⁻(K₂ = 3.07 × 10² dm³ mol⁻¹ ) where the complexation constant K₁ = [βCD.BNS⁻]/([βCD][BNS⁻] and K₂ = [βCD.(BNS⁻)₂]/([βCD.BNS⁻][BNS⁻]) in aqueous phosphate buffer at pH 7.0, I = 0.10 mol dm⁻³ and 298.2 K. For 66βCD₂su, 36βCD₂su, 33βCD₂su, 66βCD₂ur and 36βCD₂ur the analogous K₁ = 125, 74, 10.2, 364 and 16.1 (× 10⁴ dm³ mol⁻¹ ) and K₂ = 25.7, 2.30, 2.57, 17.6 and 17.2 (× 10² dm³ mol⁻¹ ), respectively. For the dimerisation of BNS⁻ K[subscript]d = 2.63 × 10² dm³ mol⁻¹ . Fluorimetric studies showed that the complexation stability for βCD.BNS⁻, forms βCD. BNS⁻, 66βCD₂su.BNS⁻, 36βCD₂su.BNS⁻, 33βCD₂su. BNS⁻, 66βCD₂ur.BNS⁻ and 36βCD₂ur. BNS⁻ characterized by K₁ = 4.67, 330, 101, 11.0, 435 and 29.6 (× 10⁴ dm³ mol⁻¹ ), respectively. The factors affecting the variations in these data are discussed. The enantioselectivity of substituted βCDs 6 [superscript]A -[bis (carboxylatomethyl)amino]-6 [superscript]A -deoxy-β-cyclodextrin (6βCDidaH₂) and (2 [superscript]A S,3 [superscript]A S)-3 [superscript]A -[bis(carboxylatomethyl)amino]-3[superscript]A -deoxy-β-cyclodextrin (3βCDidaH₂) and 6 [superscript]A -[tris(carboxylatomethyl)(2- aminoethyl)amino]-6 [superscript]A -deoxy-β-cyclodextrin (6βCDedtaH₃) and their Eu³ ⁺ complexes in forming host-guest complexes with six enantiomeric guests in D₂O was studied by 1D and 2D ¹H NMR (600 MHz) spectroscopy. The guests are D/L-tryptophanate (Trp⁻), 4-hydroxyl-D/L-phenylglycinate (4HOPhg⁻), D/L-histidinate (His⁻), D/L-pheniramine (Phm), D/L-phenylglycinate (Phg⁻) and (D/L)-β-phenylserinate (βPhs⁻). Enantioselective host-guest complexation was observed between the [Eu(6βCDida)]⁺ , [Eu(3βCDida)]⁺ and [Eu(6βCDedta)] complexes and Trp⁻, [Eu(6βCDida)]⁺ and [Eu(3βCDida)]⁺ and 4HOPhg⁻, and βCD, 6βCDida²⁻, 3βCDida²⁻, 6βCDedta³⁻ and the Eu³⁺complexes of the three substituted βCDs and Phm. The His⁻, Phg⁻ and βPhs⁻ enantiomers showed no evidence for selective host-guest complexation. The preparation of 3βCDidaH₂ and 6βCDedtaH₃ and the determination of their pK[subscript]a s are also reported. In collaboration with the research group of Prof. Matthew A. Tarr, (University of New Orleans, USA), the 6βCDida²⁻ and the 6βCDedta³⁻ has been utilized to improve Fenton oxidation of aromatic pollutants. To further support to this work, the binary complexation of Fe² ⁺ by 6βCDida²⁻ has been studied by potentiometric titrations. A series of six modified poly(acrylic acid)s 3% substituted with either βCD or the adamantyl moiety with different length of substituent chain was synthesised. To advance the understanding and control of aqueous supramolecular assembly, the host-guest interactions between the βCD substituted poly(acrylic acid)s and adamantane-1-carboxylic; adamantyl substituted poly(acrylic acid)s with βCD and linked βCD dimers; and between both βCD and adamantyl substituted poly(acrylic acid)s have been studied.
http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1311237
Thesis (Ph.D.) -- University of Adelaide, School of Chemistry and Physics, 2008
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22

Boyle, David. "Surface Complexation Modelling of the Adsorption of Cd(II), Cu(II), and Ni(II) to the Roots of Triticum turgidum." Thesis, 2012. http://hdl.handle.net/10214/5315.

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The goal of this study was to characterize the binding sites on the surface of wheat roots, Triticum turgidum, involved in the adsorption of protons and metals, and quantify the thermodynamic constants needed for a surface complexation model to predict metal binding. The adsorption of protons, Cd(II), Cu(II), and Ni(II) to the root surface as a function of pH and ionic strength in single metal exposure scenarios was quantitatively described using potentiometric titrations, batch metal adsorption experiments, and the least squares fitting program FITEQL. Model predictions from single metal exposures were compared to measured metal adsorption concentrations when roots were exposed to binary and ternary combinations of the metals. Proton dissociation was a function of three discrete monoprotic acid sites on the root surface with log proton dissociation constants of -4.50, -6.23, and -7.37 respectively, upon which varied ionic strength had no effect. The total proton binding capacities for the three sites were 2.58 x 10-4, 1.29 x 10-4, and 2.58 x 10-4 M, respectively. Metal complexation was best described by a two-site model having conditional stability constant log values of 3.04 and 3.30 for Cd(II), 3.21 and 3.25 for Cu(II), and 2.83 and 2.84 for Ni(II) at ionic strength 0.01M. At ionic strength 0.1 M the conditional stability constants log values were 2.37 and 3.36 for Cd(II), 3.11 and 2.56 for Cu(II), and 2.18 and 3.00 for Ni(II). When roots were exposed to binary or ternary mixtures of the metals, the two monoprotic acid single metal model did not provide ideal fits to the data indicating that adsorption in a metal mixture scenario cannot be considered additive and is dependent on the combination of metals present in the exposure environment. The experimentally determined proton dissociation constants and metal stability constants could be used in commercial geochemical speciation programs such as Visual MINTEQ to predict metal adsorption to plants.
Natural Sciences and Engineering Research Council of Canada, The Mining Association of Canada, Ontario Power Generation, Environment Canada.
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23

Скосырева, Н. С., and N. S. Skosyreva. "Электрохимическое определение серебра как основного антибактериального компонента в фармацевтической субстанции и готовой лекарственной форме : магистерская диссертация." Master's thesis, 2016. http://hdl.handle.net/10995/44388.

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Объектами исследования служили фармацевтическая субстанция «Аргамид» и готовая лекарственная форма 1% крем «Аргамид» на основе серебряной соли сульфадимидина (Приоритетная справка на выдачу патента № 2015153574 от 14.12.2015). Данная соль и лекарственные средства на ее основе были разработаны на базе кафедры фармации УГМУ с целью обеспечения российского фармацевтического рынка эффективными антибактериальными и ранозаживляющими лекарственными препаратами отечественного производства согласно стратегии развития фармацевтической промышленности «ФАРМА-2020». Цель работы: разработка и валидация методик количественного определения серебра в исследуемых лекарственных средствах. Анализ литературных данных показал, что оптимальным методом определения серебра является метод осадительного титрования с потенциометрической индикацией конечной точки титрования. При этом, учитывая содержание серебра в анализируемых лекарственных средствах, для его определения в субстанции был выбран метод роданометрического, а в готовой лекарственной форме – йодометрического титрования. Для анализируемых лекарственных средств были подобраны оптимальные условия пробоподготовки: масса навески, концентрация растворителя; время и температура обработки пробы. В качестве индикаторного вместо дорогостоящего импортного серебряного дискового электрода использовали отечественный толстопленочный серебросодержащий электрод. Положительные результаты валидационной оценки разработанных методик, проведенной согласно требованиям Государственной Фармакопеи РФ XIII изд., позволяют считать их приемлемыми и рекомендовать для включения в проекты фармакопейных статей на исследуемые лекарственные средства. Контроль содержания серебра по разработанным методикам не требует дорогостоящего оборудования, привлечения высококвалифицированного персонала, отличается относительно коротким временем анализа, а, следовательно, может применяться испытательными лабораториями предприятия в процессе производства и центрами контроля качества во время обращения на фармацевтическом рынке исследуемых лекарственных средств.
The objects of study were pharmaceutical substance "Argamid" and finished dosage form of 1% cream "Argamid" based on silver salt sulfadimidine (Priority reference patent number 2015153574 from 14.12.2015). This salt and drugs based on it have been developed at the Department of Pharmacy UGMU to ensure that the Russian pharmaceutical market effective antibacterial and wound healing medicines domestic production according to the strategy of development of the pharmaceutical industry "Pharma 2020". Objective: Development and validation of methods of quantitative determination of silver in the investigational medicinal product. Analysis of published data shows that the best method of determining silver is the method of precipitation titration with potentiometric indication end point. However, given the content of silver in the analyzed medicaments for identification substance rodanometricheskogo method was selected, and in the final dosage form - iodometric titration. optimal conditions for sample preparation were selected to be analyzed drugs: sample weight, the concentration of solvent; Sample processing time and temperature. As an indicator instead of expensive imported silver disk electrode used domestic thick-film silver-electrode. Positive results validation assessment developed techniques conducted in accordance with the requirements of the RF State Pharmacopoeia XIII ed., Allow us to consider them acceptable and recommended for inclusion in the draft articles on the pharmacopoeia investigational medicinal products. Control of the silver content by developed techniques does not require expensive equipment, highly skilled personnel, has a relatively short analysis time, and, therefore, can be applied testing laboratories of the enterprise in the production process and quality control center during handling in the pharmaceutical market of investigational medicinal products.
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