Capillary electrophoresis is a generic term used to describe separation techniques employing high voltages. In its simplest form, capillary zone electrophoresis (CZE), separations are based on the differential migration of charged analytes under the influence of a high electric field. CZE offers several advantages over other separation techniques, such as high performance liquid chromatography (HPLC). These include higher separation efficiency, enhanced resolution and reduced analysis time. In addition, small injection volumes (nanolitres cf. microlitres for HPLC) and low solvent consumption make CZE an attractive alternative to HPLC. Unfortunately, CZE is not amenable to neutral species, therefore alternative electroseparation methods are employed for neutrals, e.g. capillary electrochromatography (CEC) and micellar electrokinetic chromatography (MEKC), so therefore CZE can be treated as a complementary technique to HPLC.Mass spectrometry (MS) has previously been demonstrated to be a sensitive, selective and near-universal detector. Analytes must be ionised in order to be detected; thus, CZE (which also requires ions) seems an ideal separation technique for combining with MS.CZE/MS interfacing would seem problematic; the linear flow velocity through the capillary is significantly less than that required by appropriate MS ionisation sources (e.g. continuous-flow fast atom bombardment and electrospray). In addition, it is necessary to provide a ground for the separation voltage within the interface. However, interfacing of CZE and MS was first reported in 1987. Since then three distinct interface designs have been developed, co-axial sheath flow, liquid junction and the use of a low flow electrospray (nanospray) interface. Co-axial sheath flow and liquid junction methods serve to increase the overall flow rate of CZE to a suitable level for MS, whereas nanospray is a low flow ionisation technique that accepts similar flow rates to those provided by CZE.The work presented in this thesis details the off-line development of a CZE separation of a pharmaceutical product (cimetidine) and related impurities. The separation was then transferred to mass spectral detection on a commercial triple quadrupole MS instrument employing home-built co-axial sheath flow (electrospray) and nanospray interfaces and the data obtained evaluated. The separation was subsequently transferred to an orthogonal acceleration time-of-flight MS (oa-ToF) for the exact mass determination of the narrow electrophoretic peaks. The feasibility of hydrogen/deuterium exchange via the sheath liquid for CZE/MS has been investigated using model pharmaceutical compounds and preliminary work is presented. An application of CZE/MS for the separation of nicotine and ten of its metabolites has been developed. This method could be further developed into a quantitative assay for nicotine metabolites in biological fluids and suggestions for future work in this area are made.

L'utilisation croissante d'acides organiques dans l'industrie alimentaire, chimique et pharmaceutique entraîne le développement de nouvelles technologies pour leur isolement, séparation et concentration à partir de solutions complexes. Les procédés électro-membranaires constituent une voie prometteuse. Afin d'intensifier ces procédés, il est nécessaire de mieux comprendre les mécanismes de transport de la solution d'ampholytes dans le système électromembranaire souvent couplé à des réactions chimiques. La composition des formes ioniques peut en effet varier en fonction du pH de la solution. Les principaux objectifs de ce travail sont l'étude du comportement des systèmes membranaires contenant des solutions d'ampholytes dans un état d'équilibre (sans force de transfert ou sous très faible courant alternatif), et hors d'équilibre en régime d'électrodialyse (application d'un courant). Dans les deux cas, l'approche comprend une partie expérimentale et une partie théorique de caractérisation de transport de solution complexe. Dans la cadre de la modélisation associée, on a développé un modèle de système membranaire qui permet d'accéder à la distribution des formes d'ampholyte à l'intérieur et à l'extérieur de la membrane en fonction des paramètres externes.Les résultats de la comparaison des données expérimentales et de simulation de systèmes membranaires montre et explique les spécificités des mécanismes de transfert des ions d'ampholyte associés aux changements du pH de la solution au cours de l'électrodialyse. / The wide application of organic acids in the food, chemical and pharmaceutical industry is responsible for the increased interest in the development of new technologies for their isolation, separation and concentration from the complex solutions. The electro-membrane processes are promising. The difficulty to understand the transport mechanisms of the amphoteric solution in the electromembrane system is the coupling of chemical reactions: the ionic forms composition can vary depending on the pH of the solution.The main objectives are the study of the behavior of membrane systems containing ampholyte solutions in a steady state (without transfer force or under very low AC) and in a non-equilibrium state such as in electrodialysis regime (applying a current). In both cases, a study includes the experimental and theoretical parts of characterization of the complex solution transport. In the context of modeling a model of the membrane system which can calculate the ampholyte form distribution inside and outside the membrane depending on the external parameters was developed.The comparison of experimental data and results obtained from the simulation of membrane systems containing ampholytes solutions, shows and explains the specific features in the transfer mechanism of ampholyte ions which associated with changes of the solution pH during electrodialysis and, as a consequence, with modification of ampholyte forms.

Zinc electrodeposition is currently a hot topic because of its widespread use in rechargeable zinc-air batteries. However, Zn deposition has received little attention in organic solvents with much higher ionic conductivity and current efficiency. In this study, a Zn-betaine complex is synthesized by using ZnO and betainium bis[(trifluoromethyl)sulfonyl]imide and its electrochemical behavior for six organic solvents and electrodeposited morphology are studied. Acetonitrile allowed dendrite-free Zn electrodeposition at room temperature with current efficiencies of up to 86%. From acetonitrile solutions in which Zn, Pb, and Cu complexes are dissolved in high concentrations, Zn and Pb/Cu are efficiently separated electrolytically under potentiostatic control, allowing the purification of solutions prepared directly from natural ores. Additionally, a highly flexible Zn anode with excellent kinetics is obtained by using a carbon fabric substrate. A rechargeable zinc-air battery with these electrodes shows an open-circuit voltage of 1.63 V, is stable for at least 75 cycles at 0.5 mAcm⁻² or 33 cycles at 20 mAcm⁻², and allows intermediate cycling at 100 mAcm⁻².