Dissertations / Theses: 'Voltammetry'

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Rees, Neil V. "Innovations in voltammetry." Thesis, University of Oxford, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.408686.

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Wildgoose, Gregory G. "Modified electrode voltammetry." Thesis, University of Oxford, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.432263.

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Adra, Mahmoud. "Voltammetry using microdevices." Thesis, University of Bath, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.428375.

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Limon, Petersen Juan Gualberto. "Weakly supported voltammetry." Thesis, University of Oxford, 2010. http://ora.ox.ac.uk/objects/uuid:c14f972c-8653-41c2-b2d1-b080e691e4dc.

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This thesis is concerned with dynamic electrochemical experiments with different concentrations of supporting electrolyte. Normally supporting electrolyte is added to a solution in order to avoid undesirable effects as migration and potential drop in solution. However, in the present thesis we focus on the study and understanding of such effects as the concentration of supporting electrolyte decreases. First a theoretical treatment is proposed, based on numerical simulation using the Nernst-Planck- Poisson system of equations. The theoretical treatment is compared with previous works as electroneutrality, the differences between both models are explained. The model is also compared with theoretical results to validate the theoretical treatment. Experimental results of chronoamperometry and cyclic voltammograms are compared with theoretical results obtaining remarkable agreement. Is noteworthy that to the best of the author’s knowledge this is the first time that experimental dynamic voltammetry under weakly supported conditions has been successfully modeled by a theoretical treatment. The electrochemical reaction of a non-charged electroactive species is presented for the system ferrocene/ferrocenium in acetonitrile in which the oxidized and reduced species are soluble in solution, the reaction is studied at different concentrations of supporting electrolyte. Comparison is presented between theoretical simulations and experimental results, for which potential drop in solution is studied. Then systems involving charged electroactive species are treated, in these cases the decrease of supporting electrolyte influence the mass transport of the electroactive species due to migration, comparison between different experimental systems as hexaammineruthenium (III)/(II), cobaltoceniun/cobaltocene and hexacyanoferrate (III)/(II) are presented in comparison with theoretical simulations. More complex mechanistic paths are also investigated, such as deposition and stripping, in which it is established that the level of support required to achieve ‘diffusion only’ voltammetry is on dependence of the concentration of amalgamated electroactive species prior to the stripping step. Comparison between theoretical simulation and experimental results of the deposition and stripping of thallium at a mercury hemisphere are presented, and found to be in good agreement for either chronoamperometry and cyclic voltammetry Simulations are also presented showing the necessary required amount of supporting electrolyte required to achieve ‘diffusion only’ cyclic voltammetry. This is obtained by comparison between diffusion only software and the simulation described in the present thesis. The required amount of supporting electrolyte is shown to depend on the concentration of the electroactive species and supporting electrolyte in the media, the electrode radius, the diffusion coefficient of species and the scan rate. Finally, the cyclic voltammetry in weakly supporting media is used to obtain mechanistic information, by using the migration of electroactive species to differentiate the mass transport of electroactive species to the electrode. The two single electron reductions of anthraquinone in acetonitrile is presented, and the comproportionation mechanistic path is observed in weakly supported media, diffusion only voltammetry is normally unable to present whether this mechanism path takes place, due to the similarity in diffusion coefficients of the electroactive species. In contrast in weakly support conditions the diffusion controlled comproportionation mechanistic path is observed experimentally and constraints for the rate constant are discussed.

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Bartlett, Thomas. "Nano-impact voltammetry." Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:05ca3e7f-fea4-4d93-9f57-e86a2c397d1f.

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This thesis introduces new concepts to the study of nanoparticles by nano-impact voltammetry. Utilising the special chemistries of metal halide and metal oxide nanoparticles, the use of the nano-impact technique is expanded beyond quantitative sizing towards the study of the in-situ synthesis and detection of nanoparticles, reversible agglomeration behaviour and the fabrication of nanoelectrode arrays. Nano-impact voltammetry is also demonstrated to be an informative tool for the tracking of chemical and photochemical conversion reactions of metal halide nanoparticles and for the mechanistic determination of metallic nanoparticle growth during synthesis. The use of forced convection to gain improvements in the detection limit achievable for the direct-impact of metallic nanoparticles is also reported. Initially, the work reported herein looks at the direct-impact voltammetry of previously unstudied nanomaterials; mercury(I) chloride, silver bromide and bismuth oxide. The first sizing of metal halide nanoparticles is reported as well as a method for synthesising particles through the electrolytic induced implosion of a nanoscale metal halide layer on a liquid electrode. The "upper-limit" of the nano-impact technique is also quantified through the use of silver bromide and silver nanoparticles with diameters approaching 100 nm successfully studied. Next, bismuth oxide nanoparticles are studied by the nano-impact method to probe the reversible agglomeration of particles. By reducing impacting bismuth oxide nanoparticles at the electrode, bismuth deposits are shown to result and can be imaged by scanning electron microscopy. Through the analysis of these deposits, in combination with nanoparticle tracking analysis, experimental evidence for the voltammetrically induced de-agglomeration of nanoparticles is proposed. In the subsequent chapter, nano-impact voltammetry is employed in the study of photochemical reactions. First, the photochemical reduction of silver bromide nanoparticles to silver nanoparticles is followed both by ultra-violet visible spectroscopy and nano-impacts, allowing mechanistic determination of the conversion process. Second, the nano-impact technique is used in combination with ultra-violet visible spectroscopy and transmission electron microscopy for the mechanistic determination of the photochemical Ostwald ripening of silver nanoprisms from silver nanoseeds. Finally, the inter-play between nano-impacts and electrode arrays is reported. Through the electrolysis of impacting silver bromide nanoparticles, it is shown that a functional silver nanoelectrode array can be formed. The formed nanoelectrode array is characterised by the electrocatalytic reduction of hydrogen peroxide. The lowest reported detection limit for silver nanoparticles is also reported, through the combination of a random array of microelectrodes and a specially developed, custom built, and characterised wall-jet flow cell.

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Nakagawa, Yasue. "Protein electrochemistry : applications of sonovoltammetry, microelectrode voltammetry and solid-state voltammetry." Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325772.

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Owens, Dale Spencer. "Voltammetry in flowing streams." Diss., Georgia Institute of Technology, 1987. http://hdl.handle.net/1853/27054.

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Helfrick, John C. "Cyclic square wave voltammetry." Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/30681.

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Fietkau, Nicole. "New directions in voltammetry." Thesis, University of Oxford, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.442948.

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Davies, Trevor J. "Voltammetry at heterogeneous electrodes." Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.427873.

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Wellington, Geoffrey R. "Novel aspects of hydrodynamic voltammetry." Thesis, University of Oxford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334277.

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Hutchings, M. J. "Voltammetry of metal dialkyldithiophosphate systems." Thesis, Cardiff University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372342.

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Meng, Luwen. "Hydrodynamically modulated voltammetry in microreactors." Thesis, University of Cambridge, 2019. https://www.repository.cam.ac.uk/handle/1810/288480.

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This thesis describes modulated methods using both voltammetric and microfluidic perturbations to study mechanisms of electrolysis reactions. The initial chapters provide an overview of applications and research development in the fields of micro-engineering and electrochemistry, including microfabrication methodology, electrochemical detection techniques and analysis methods. Some typical electrochemical reactions have been studied for different kinds of industrial applications. Also hydrodynamic modulation methods have been investigated. The result chapters begin in Chapter 3 with detailed investigation of various electrochemical reactions by using cyclic voltammetry (CV) and large amplitude Fourier transformed alternating current voltammetry (FTACV) under microfluidic conditions. Single electron transfer reactions with different kinetics were studied first by using potassium ferrocyanide and ferrocenecarboxylic acid (FCA). Dual electron transfer reactions with different pathways were investigated by using 2,5-dihydroxybenzoic acid for one step oxidation and N,N,N',N'-tetramethyl-para-phenylene-diamine (TMPD) for two consecutive one-electron step oxidation. An irreversible reaction was explored by using borohydride solution. Examples of homogeneous reaction mechanisms were studied by using the combinations of Fe(CN)64-/L-cysteine or TMPD/ascorbic acid. The current response of all the electrolysis reactions except single electron transfer reactions was first reported under microfluidic conditions with FTACV, which has shown sensitive with the change of volume flow rates and the substrate concentrations when homogeneous reactions are involved. The linear relationships between peak current and volume flow rates or substrate concentrations can be obtained in every harmonic component. In chapter 4, the modulated technique was applied to microfluidic hydrodynamic systems. A range of electrolysis mechanisms including single electron transfer reactions, dual electron transfer reactions, irreversible reaction and homogeneous reactions were studied under hydrodynamic modulated conditions. The system showed rapid response with the change of volume flow rates during one measurement. The linear relationships between peak current and flow rates, as well as substrate concentrations, can be obtained simultaneously in one scan, which reveals a promising approach to get more information in a short-time measurement. Chapter 5 demonstrated a new protocol by forcing an oscillation of the electrochemical active solution flowing. Analysis of transition time and its effect on limiting current are presented to begin exploration of this new tool for supporting researchers on understanding redox mechanisms. A short simulated study was carried out to help better understand the mechanism under different hydrodynamic conditions.

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Ward, Kristopher R. "Voltammetry of electrochemically heterogeneous surfaces." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:18190ffe-94d7-4d5a-90c8-f65568124280.

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In this thesis, mathematical modelling is used to theoretically investigate the electrochemical behaviour of surfaces which can be broadly classified as being ‘electrochemically heterogeneous’. Simulated voltammetry is used in the exploration of a number of specific systems as listed below. The cyclic voltammetry of electrodes composed of two different electroactive materials that differ in terms of their electrochemical rate constants towards any given redox couple. The effect of the distribution of the two materials was investigated and the occurrence of split peak cyclic voltammetry where two peaks are observed in the forward sweep, was studied. The technique was specifically applied to the modelling of highly-ordered pyrolytic graphite (HOPG). The steady-state voltammetry of a conducting spherical particle resting on an insulating supporting surface. An algebraic expression that completely describes the voltammetric waveform in the limit of irreversible kinetics was developed. The cyclic voltammetry of the EC′ (catalytic) mechanism at a regularly distributed array of hemispherical particles on an insulating supporting surface. Particular attention was paid to the ‘split-wave’ phenomenon, where two peaks are observed in the forward scan of a cyclic voltammogram and the conditions under which these peaks are resolvable were elucidated. The linear sweep voltammetry of micro- and nano-particle modified electrodes and other electrodes of partially covered and non-planar geometry. It was demonstrated that the apparent electrochemical rate constant of the reaction and thus the peak position of the voltammetry is dependent only on the relative electroactive surface area of the particles on the surface and not upon their shape or distribution. This has wide reaching implications as it can be used to explain some instances of a purported nano-catalytic effect without appeal to altered properties at the nanoscale. The linear sweep voltammetry of the interior of a partially electroactive cylindrical pore. Four limiting cases were observed and fully characterised. The linear sweep voltammetry of porous surfaces. It was established that if the pores are less than a certain threshold depth, then a porous surface will also display an apparent catalytic effect that is dependent on the relative electroactive surface area (including the area in the interior of the pores).

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Mizzon, Giulia. "Bioelectrochemistry by fluorescent cyclic voltammetry." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:6a1134dd-c24d-4e60-ac83-936a6918131f.

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Understanding the factors influencing the ET characteristics of redox proteins confined at an electrochemical interface is of fundamental importance from both pure (fundamental science) and applied (biosensory) perspectives. This thesis reports on progress made in the emerging field of coupled electrochemical characterization and optical imaging in moving the analysis of redox-active films to molecular scales. More specifically the combination of cyclic voltammetry and wide-field Total Internal Reflection (TIRF) microscopy, here named ‘Fluorescent Cyclic Voltammetry’ (FCV), was applied to monitoring the response of surface-confined redox active proteins at submonolayer concentrations. The combined submicrometre spatial resolution and photon capture efficiency of an inverted TIRF configuration enabled the redox reactions of localized populations of proteins to be directly imaged at scales down to a few hundreds of molecules. This represents a 6-9 orders of magnitude enhancement in sensitivity with respect to classical current signals observed in bioelectrochemical analysis. Importantly, measurements of redox potentials at this scale could be achieved from both natural and artificially designed bioelectrochemical fluorescent switches and shed fundamental light on the thermodynamic and kinetic dispersion within a population of surface confined metalloproteins. The first three chapters of this thesis provide an overview of the relevant literature and a theoretical background to both the rapidly expanding fields of electroactive monolayers bioelectrochemistry and TIRF imaging. The initial design and construction of a robust electrochemically and optically addressable fluorescent switch, crucial to the applicability of FCV is reported in chapter 5. The generation of optically transparent, and chemically modifiable electrode surfaces suitable for FCV are also described. Chapter 6 describes the response of the surface confined azurin-based switch. Analysis of the spatially-resolved redox reaction of zeptomole samples in various conditions enables the mapping of thermodynamic dispersion across the sampled areas. In chapter 7 the newly developed FCV detection method was extended to investigate more complex bioelectrochemical systems containing multiple electron transferring redox centres and responding optically at different wavelengths. This approach provides a platform for spectral resolution of different electrochemical processes on the same sample. Finally in chapter 8 an electrochemical procedure is proposed for investigating the kinetic response of redox proteins using a fundamentally new methodology based on interfacial capacitance. In using variations in the surface chemistry to tune the rate of electron transfer, the approach was shown to be a robust and facile means of characterising redox active films in considerably more detail than possible through standard electrochemical methodologies. Ultimately, it can be applied to probe dispersion within protein populations and represents a powerful means of analysing molecular films more generally.

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Ho, I.-Pin. "Instrumentation for Multi-Electrode Voltammetry." PDXScholar, 1990. https://pdxscholar.library.pdx.edu/open_access_etds/1141.

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When metal pollutants exist in natural water, their toxicity is dramatically dependent on the chemical species. Numerous sophisticated techniques and instruments have been developed to detect metal pollutants at very low concentration levels. However, one important factor is often ignored, i.e., rarely is species determination required. Electrochemical (EC) methods have the particular advantage of being, in principle, a species-sensitive method rather than an element-sensitive method for the study of metal speciation in natural waters. The goal of this research was to develop an instrument using the EC technique for speciation and general voltammetric studies. It was accomplished by designing a flow-through EC cell containing multi-electrodes to which various fixed potentials over a selected range were applied. A special potentiostat was designed to supply a selected potential to each electrode in the cell. Potential control was provided by placing a combined counter-reference electrode at circuit ground and connecting each working electrode to the inverting input of a current follower which had a potential applied to its non-inverting input from two digital-to-analog converters and a resistor network. Integrating current followers were used for measuring signal currents generated by the electrolytes samples on each electrode. A multiplexing circuit, including an analog-to-digital converter, was used to fulfill data acquisition. These circuits were interfaced to a computer and the readout was a pseudo-voltammogram which is a plot of amperometric currents versus various applied fixed potentials on each electrode. Details of the instrumentation, software, and some initial results are described.

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Turoczy, Nicholas John, and mikewood@deakin edu au. "Adsorption and voltammetry of butyltin compounds." Deakin University, 1994. http://tux.lib.deakin.edu.au./adt-VDU/public/adt-VDU20050915.154112.

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The adsorption of tributyltin onto materials commonly used for the construction of sampling and analytical equipment from aqueous solutions of varying ionic composition has been examined. The adsorption appears to be controlled by non-polar interactions between tributyltin and the surface involved. Since the speciation and hence polarity of tributyltin is affected by the ionic composition of the medium, the extent of adsorption is affected by the salinity and pH of a sample. The adsorption is rapid and, unless strategies are adopted to eliminate its effects, may render analytical results invalid. The electrochemistry of tributyltin, dibutyltin and monobutyltin, individually and in mixtures, has been investigated in aqueous media at mercury electrodes. The basic electrochemistry of each compound is summarised by the reaction BunSn (4-n)+ + (4-n)e- right left harpoons BunSn where n is the number of butyl groups attached to the tin atom. However, the electrochemistry of each compound is largely confined to the surface of the mercury electrode, and the simplicity of the above reaction is disrupted by polymerisation reactions and by butyl exchange processes occurring with the mercury electrode. When mixtures of butyltin compounds are present, the various processes that occur for each individual compound interfere with each other. A direct voltaminetric method for the determination of butyltin compounds in natural waters is therefore probably not possible.

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Dai, Xuan. "Sensing of arsenic via stripping voltammetry." Thesis, University of Oxford, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.440152.

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Campbell, Fallyn Wilson. "The voltammetry of metallic nanoparticle arrays." Thesis, University of Oxford, 2010. http://ora.ox.ac.uk/objects/uuid:201062ee-7a30-4fd5-a461-5581a5115458.

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The experimental work discussed in this thesis examines the effect of voltammetry of nanoparticle arrays with a specific focus on the effect of nanoparticle size and surface coverage on the substrate electrode. These effects are investigated in relation to the reduction of hydrogen peroxide, 4-nitrophenol and the hydrogen evolution reaction. In each case, the experimental data obtained is subsequently fitted using numerical simulations to extract quantitative kinetic data. Distinct differences are noted between macro – and nano – scale. The reduction of H₂O₂ reveals the absence of autocatalysis at the nano – scale. Furthermore, peak potential shifts positively with surface coverage under Case 3 diffusion conditions. On the other hand, at essentially isolated particles (Case 1) E_p varies logarithmically with nanoparticle radius. By decreasing nanoparticle size, we promote convergent diffusion and enhance irreversibility of the process. The shift in E_p with surface coverage can be accounted for as the diffusion layers begin to overlap heavily, tending towards more macro – disk type behaviour. We also study the hydrogen evolution reaction at an array of AgNPs. By fitting of the experimental data with numerical simulations we demonstrate altered kinetics between the macro – and nano – scale. Voltammetry at AgNP – arrays also display dependence between surface coverage and current. We attribute this to increased electro – active surface area and decrease in irreversibility of the process, with increasing surface coverage. Numerical simulations are also used to fit experimental data obtained for the reduction of 4 – nitrophenol in acidic media. The AgNP – arrays exhibit significantly different electrode kinetics compared to a macro – disk. Examination of the data obtained for AgNP – arrays at two different acid concentrations implies the rate - determining step is likely the electron transfer process. We therefore infer a change in α the mechanism of the rate – determining step between macro – and nano – scale. An unusually low value of α at the NP – array may indicate that adsorption plays some role in the process. Furthermore, we discuss the size – dependent adsorption behaviour exhibited by silver nanoparticle arrays, such that small particles with diameters below ~ 50 nm do not display the typical underpotential deposition characteristics of corresponding bulk materials or larger nanoparticles. This phenomenon is reported for the deposition of heavy metals (thallium, lead and cadmium) at silver nanoparticle arrays. The stripping voltammetry of arrays of silver nanoparticles has also been investigated. The stripping peak potential is dependent on the degree of surface coverage. Modelling of this system has shown that a one – dimensional diffusion model is appropriate for high surface coverage; essentially it is experiencing planar diffusion. However, for an array of widely dispersed particles, the individual nanoparticle size and convergent diffusion begin to dominate behaviour. A detailed overview of the literature is first discussed, relating to the synthesis of a wide variety of metallic nanoparticles and their practical applications, such as the determination of pH using platinum nanoparticles as covered in Chapter 7. We also discuss the fundamental principles governing the voltammetric behaviour of nanoparticles.

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Ertas, Fatma Nil. "Cathodic stripping voltammetry of peptide complexes." Thesis, Loughborough University, 1993. https://dspace.lboro.ac.uk/2134/33110.

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Small peptides containing the histidine residue are considered as models of the metal binding site of bioactive peptides and proteins. The present study has been concerned with the cathodic stripping voltammetry of the copper complexes of imidazole (the parent molecule), and several histidine containing peptides; glycylglycyl-L-histidine (GGH), glycyl-L-histidylglycine (GHG), L-histidylglycine (HG), glycyl-L-histidine (GH), Carnosine (Car) and thyrotropine releasing factor(TRF). Accumulation and reduction mechanisms were further studied by cyclic voltammetry, and indirect cathodic stripping voltammetric method of determining these peptides has been developed.

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Hadjichari, Andrew Michael, University of Western Sydney, and School of Civic Engineering and Environment. "Determination of heavy metals on macro- and micro-electrodes by adsorptive cathodic stripping voltammetry and anodic stripping voltammetry." THESIS_XXXX_CEE_Hadjichari_A.xml, 1999. http://handle.uws.edu.au:8081/1959.7/602.

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This thesis describes the application of macro, micro, ultra-microelectrodes and microelectrode arrays to the measurement of trace concentrations of nickel and cobalt in sediment and natural waters by adsorptive cathodic stripping voltammetric methods. In addition the measurement of tin by adsorptive cathodic stripping voltammetry in sediment and natural waters is discussed. Also, the application of macroelectrodes and microelectrode arrays to the measurement of lead, cadmium and zinc in sediment and natural waters by anodic stripping voltammetry is considered. In all cases the determination of the six metals was optimised by investigating the influence of various significant parameters, such as in-situ mercury plating, complexing agent concentration, scan rate, pulse height, accumulation time and potential, buffer concentration and pH. The results obtained for these investigations are discussed in this thesis
Doctor of Philosophy (PhD)

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Hadjichari, Andrew Michael. "Determination of heavy metals on macro- and micro-electrodes by adsorptive cathodic stripping voltammetry and anodic stripping voltammetry." Thesis, View thesis, 1999. http://handle.uws.edu.au:8081/1959.7/602.

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This thesis describes the application of macro, micro, ultra-microelectrodes and microelectrode arrays to the measurement of trace concentrations of nickel and cobalt in sediment and natural waters by adsorptive cathodic stripping voltammetric methods. In addition the measurement of tin by adsorptive cathodic stripping voltammetry in sediment and natural waters is discussed. Also, the application of macroelectrodes and microelectrode arrays to the measurement of lead, cadmium and zinc in sediment and natural waters by anodic stripping voltammetry is considered. In all cases the determination of the six metals was optimised by investigating the influence of various significant parameters, such as in-situ mercury plating, complexing agent concentration, scan rate, pulse height, accumulation time and potential, buffer concentration and pH. The results obtained for these investigations are discussed in this thesis

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Hadjichari, Andrew Michael. "Determination of heavy metals on macro- and micro-electrodes by adsorptive cathodic stripping voltammetry and anodic stripping voltammetry /." View thesis, 1999. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20030828.122855/index.html.

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Thesis (Ph. D) -- University of Western Sydney, Nepean, 1999.
A thesis presented for the degree of Doctor of Philosophy, Centre for Electrochemical Research and Analytical Technology, University of Western Sydney, Nepean. Includes bibliographical references.

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Gerhardt, Geoff C. "Square-wave voltammetry detection for capillary electrophoresis." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0015/NQ43512.pdf.

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Mishchenchuk, V. V. "Improvement of the RDE stationary voltammetry method." Thesis, БДМУ, 2020. http://dspace.bsmu.edu.ua:8080/xmlui/handle/123456789/18367.

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Schuette, Sheila A. "Trace voltammetry using microelectrodes and modulation techniques /." The Ohio State University, 1987. http://rave.ohiolink.edu/etdc/view?acc_num=osu14873257407203.

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Kollipara, Suresh Babu. "Organic Electrochemical Transistors for Fast Scan Cyclic Voltammetry." Thesis, Linköpings universitet, Fysik och elektroteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-98676.

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The work presented in the thesis is about the evaluation of Organic Electrochemical Transistors (OECTs) for fast scan cyclic voltammetry (FSCV). FSCV is a method which has been used for real time dopamine sensing both in vivo and in vitro. The method is sensitive to noise and could therefore benefit from signal preamplification at the point of sensing, which could be achieved by incorporation of OECTs. In this study the OECTs are based on the conductive polymer poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS). The gate consists of gold microelectrodes of different sizes to be used one at a time. When dopamine is reacted at the gate electrode, the redox state of the PEDOT:PSS OECT channel is modulated and the resulting change in drain current can be measured. The gate current, which contains the sensing information, is after filtering obtained by differentiating the channel potential with respect to time. The derived gate current is plotted in cyclic voltammogram for different dopamine concentrations and the amplitude of the oxidation/reduction peaks can be used to determine the dopamine concentration. In this thesis for the first time it is demonstrated that OECTs can be used for FSCV detection of dopamine. The results are discussed and an outlook on future work is given.

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McEvoy, James P. "Temperature and solvent effects in protein film voltammetry." Thesis, University of Oxford, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249424.

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Bateman, Libei. "Studies of heme proteins using protein film voltammetry." Thesis, University of Oxford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289588.

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Tait, Russell John, and mikewood@deakin edu au. "Development and application of a microelectrode based scanning voltammetric detector." Deakin University. School of Physical and Chemical Sciences, 1991. http://tux.lib.deakin.edu.au./adt-VDU/public/adt-VDU20060720.100447.

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A large part of the work presented in this thesis describes the development and use of a novel electrochemical detector designed to allow the electrochemical characterisation of compounds in flowing solution by means of cyclic voltammetry. The detector was microprocessor controlled, which provides digital generation of the potential waveform and collection of data for subsequent analysis. Microdisk working electrodes are employed to permit both thermodynamic and kinetically controlled processes to be studied under steady-state conditions in flowing solutions without the distortion or hysteresis normally encountered with larger sized electrodes. The effect of electrode size, potential scan rate, and solution flow rate are studied extensively with the oxidation of ferrocene used as an example of a thermodynamically controlled process and a series of catecholamines as examples of a kinetically controlled process. The performance of the detector was best demonstrated when used as a HPLC post-column detector. The 3-dimensional chromatovoltammograms obtained allow on-line characterisation of each fraction as it elutes from the column. The rest of the work presented in this thesis involves the study of the oxidative degradation pathway of dithranol. The oxidative pathway was shown to involve a complex free radical mechanism, dependent on the presence of both oxygen and, in particular light. The pathway is further complicated by the fact that dithranol may exist in either a keto or enol form, the enol being most susceptible to oxidation. A likely mechanism is proposed from studies performed with cyclic voltammetry and controlled potential electrolysis, then defined by subsequent kinetic studies.

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Lowens, Michael James. "Studies on polypyrrole chemically modified electrodes for analytical voltammetry." Thesis, University of Salford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299127.

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Colombo, Carlo Maurizio. "Flow analysis of trace metals in seawater by voltammetry." Thesis, University of Liverpool, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338581.

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Adamson, Hope. "Probing biological redox chemistry with Fourier Transformed ac Voltammetry." Thesis, University of York, 2017. http://etheses.whiterose.ac.uk/17930/.

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Biological electron transfer is fundamental to life on earth. Photosynthesis, respiration and many other biological processes are underpinned by electron transfer between redox proteins and catalysis by redox enzymes. Fully understanding the mechanisms of redox biology is crucial to understanding life and inspiration for chemical, biomedical and future energy technologies can be taken from Nature’s fine example. Developments in techniques and data analysis are required to gain a deeper understanding of biological electron transfer and redox catalysis. Protein film electrochemistry has enabled mechanistic insight into protein redox chemistry but has distinct limitations in the study of non-catalytic electron transfer as opposed to catalytic reactions. This thesis outlines the insight into biological redox chemistry gained through development of Fourier Transformed ac Voltammetry and associated analysis, in combination with spectroscopic, biochemical and molecular biology approaches. Novel pyranopterin ligand redox chemistry is proposed to control catalysis in a molybdoenzyme YedY, reversible disulphide bond redox chemistry is confirmed in a [NiFe]-hydrogenase maturation protein and an iron-sulphur cluster relay site distant from the active site is shown to influence the key catalytic properties of overpotential and bias in an O2-tolerant [NiFe]-hydrogenase.

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Tichter, Tim [Verfasser]. "Theory of Cyclic Voltammetry at Macroporous Electrodes / Tim Tichter." Berlin : Freie Universität Berlin, 2020. http://d-nb.info/1220288314/34.

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MacKnight, Eric. "An Autonomous, On-Site Sampling / Analyzing System for Measuring Heavy Metal Ions in Ground Water." University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1226769402.

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Pershad, Harsh R. "Studies of redox proteins and enzymes using protein-film voltammetry." Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325777.

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37

Moreira, Josino Costa. "Adsorptive stripping voltammetry of derivatized biological molecules and metal complexes." Thesis, Loughborough University, 1991. https://dspace.lboro.ac.uk/2134/14142.

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Differential pulse stripping voltammetry preceded by a non-faradaic preconcentration step is a very powerful technique for the direct determination of metal complexes, drug compounds and proteins. Small molecules like the amino acids can play a very important role in the biochemistry of living organisms. Despite their importance, these substances (except for cystine and cysteine) are generally not strongly adsorbed on mercury and /or do not possess any electroactive group in their molecular structure making their determination by direct electroanalytical techniques difficult or even impossible. These difficulties can be overcome by reacting these compounds with derivatising reagents (1). Initially here, derivatisation techniques for the determination of amino acids were studied. Methods are presented for the determination of tyrosine and histidine after coupling with diazotised sulphanilic acid (chapter 3) and for amino acids in general, and glycine in particular, as methyl or phenylthiohydantoin derivatives (chapter 5). Nanomolar levels of histidine were determined by accumulating the amino acid in the presence of an excess of copper(II) using the reduction peak of its copper(II) complex (chapter 4) for detection. The uses of polyamino acids as electrode modifiers were also studied and a method for the determination of copper(II) based on its accumulation at a hanging mercury electrode modified by adsorption of a polyhistidine film (chapter 6) and of hexacyanoferrate(III) after preconcentration on a copper modified polylysine film electrode (chapter 7) are proposed. As an offshoot of the diazo coupling derivatization of tyrosine and histidine, a method for the determination of copper(ll) by reaction with diazo-1 H-tetrazole (DHT) and accumulation of its complex on the HMDE (chapter 8) is presented.

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38

Brubaker, Joel Patrick. "A Diffusion Model for Cyclic Voltammetry with Nanostructured Electrode Surfaces." University of Dayton / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1418273596.

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39

Luscombe, Darryl L., and mikewood@deakin edu au. "Studies with voltammetric microdisk electrodes." Deakin University. School of Sciences, 1991. http://tux.lib.deakin.edu.au./adt-VDU/public/adt-VDU20051201.153433.

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40

Alden, John. "Computational electrochemistry." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297935.

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Bolinger, Roman Wilhelm. "The deployment of digital simulation tools to verify cyclic voltammetry experiments /." Zürich, 2000. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=13637.

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42

Ramjuttun, Ravindlall. "The chemical speciation of chromium in seawater by Cathodic stripping voltammetry." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0018/NQ47509.pdf.

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43

Wengenack, Nancy L. "Design and testing of a computer-controlled square wave voltammetry instrument /." Online version of thesis, 1987. http://hdl.handle.net/1850/8853.

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Camba, Acosta Raul O. "Reaction mechanisms of iron-sulfur proteins studied by protein-film voltammetry." Thesis, University of Oxford, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365860.

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45

Ghita, Mihaela. "Studies of modified electrodes and liquid-liquid interfaces for analytical voltammetry." Thesis, University of Salford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400774.

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46

Moura, Campos M. Lucia A. de. "Determination of copper speciation in sea water by cathodic stripping voltammetry." Thesis, University of Liverpool, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316703.

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47

Le, Gall Anne Christine. "Determination of glutathione and folic acid in natural waters using voltammetry." Thesis, University of Liverpool, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317001.

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Stevenson, Gareth P. "Mathematical modelling of ac voltammetry and its application in electrochemistry and bioelectrochemistry." Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.540287.

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Barlow, Nicola Louise. "Investigation of novel methods for the advancement of novel protein film voltammetry." Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426382.

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50

Gruden, Roman, Andreas Buchholz, and Olfa Kanoun. "Electrochemical analysis of water and suds by impedance spectroscopy and cyclic voltammetry." Universitätsbibliothek Chemnitz, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-149036.

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Abstract:

Optimum detergent dosage during a washing process depends on water quality, degree of pollution and quantity of laundry. Particularly, water quality is an important factor. Other parameters like carbonate- or non-carbonate hardness and calcium / magnesium (Ca / Mg) ratio in addition to total hardness of water have an impact on the amount of detergent. This work discusses the possibilities realizing a detergent sensor that measures important parameters for the washing process and assess the ideal necessary amount of detergent during the washing process. The approach is to combine impedance spectroscopy with cyclic voltammetry in order to determine both water quality and concentration of detergent in the suds which build up the basis for an optimum detergent dosage. The results of cyclic voltammetry show that it is possible to identify the Ca / Mg ratio and the carbonate hardness separately, which is necessary for the optimization of the washing process. Impedance measurements identify total hardness and detergent concentrations.

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Dissertations / Theses on the topic 'Voltammetry'

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