A atmosfera, ao lado dos principais gases que a compõe, apresenta em menores concentrações milhares de compostos químicos (orgânicos e inorgânicos) distribuídos nas fases líquidas e gasosa ou no material particulado. Quando esses compostos encontrados no ar apresentam níveis de concentração que os tornam impróprios ou nocivos à saúde humana, aos animais ou vegetais e danosos aos materiais, são considerados poluentes atmosféricos. Neste trabalho, enfatizou-se o estabelecimento de métodos alternativos, eficientes e práticos, para a amostragem de várias espécies que participam dos processos de acidificação da atmosfera, assim corno o desenvolvimento de métodos analíticos baseados em técnicas eletroanalíticas em fluxo como a amperometria e a eletroforese capilar com detecção condutométrica sem contato. Devido a algumas limitações das técnicas de amostragem, explorou-se a alternativa de recorrer a tubos capilares com paredes microporosas, preenchidos com solução adequada à absorção das espécies em pauta, após sua difusão através dos poros da membrana hidrófoba. Assim, construiu-se um coletor por difusão utilizando-se tubo de Teflon®, dentro do qual foi introduzido um feixe de tubos capilares porosos de polipropileno. A união desta técnica de amostragem com a determinação seletiva e quantitativa dos analitos por eletroforese capilar com detecção condutométrica (CE-CCD) possibilitou o desenvolvimento de métodos completos para as seguintes espécies: CH2O coletado em água deionizada, à freqüência de 1 amostra por hora, seguido de derivatização com HSO3- para determinação de fonnaldeído na forma de hidroximetanossulfonato (HMS); HCOOH e H3C2OOH- com o mesmo procedimento de coleta e separação por CE-CCD aplicado na detenninação de CH2O na forma de HMS; e NH3 - coletado em solução de HCl e determinado na forma de NH4+ por CE-CCD. Outra espécie de interesse ambiental é o H2O2, por participar de várias reações de oxidação tanto na fase gasosa corno na fase líquida da atmosfera, contribuindo assim para a acidez da atmosfera. A detenninação analítica do H2O2 foi feita por método FIA amperométrico com eletrodo de gota pendente de mercúrio, adaptando-se célula eletroquímica estacionária ao trabalho em fluxo. Duas formas de coleta de H2O2 na fase gasosa foram desenvolvidas e comparadas: . coleta por difusão - com fluxo de água deionizada pelos feixe de filamentos capilares; nesta aplicação, o feixe foi conectado diretamente à alça de amostragem do injetor, proporcionando determinações on-line\". . amostragem criogênica em dispositivo \"passivo\" - aproveitando o fato conhecido de que a razão H2O:H2O2 da fase gasosa se mantém praticamente inalterada na fase sólida (gelo coletado). Além das determinações de H2O2 na fase gasosa, o método FIA-Amperométrico foi utilizado, em trabalhos realizados em parceria com pesquisadores do IPEN, para determinação dessa espécie em efluentes e água de cultivo do microcrustáceo Daphnia similis após serem irradiados com feixes de elétrons. Paralelamente às pesquisas relacionadas a espécies gasosas, desenvolveu-se metodologia para a determinação de cátions e ânions majoritários em água de chuva, recorrendo à CE-CCD, de modo a oferecer uma alternativa à consagrada técnica da cromatografia de íons, demorada e onerosa. Os estudos iniciais da composição iônica da chuva foram feitos com coletas de água de chuva efetuadas no período de Abril/97 a Março/98. Nesse conjunto de amostras determinou-se as concentrações dos cátions (NH4+, Ca2+, K+ e Na+) e dos ânions (NO3-, SO42- e Cl-), além das usuais medições de pH e condutividade. A Eletroforese Capilar mostrou-se particularmente tàvorável para a determinação dos íons majoritários em água de chuva. Embora fugindo da área ambiental, desenvolveu-se metodologia para determinação de espécies de S(IV) em amostras de vinho, a partir de algumas adaptações de método amperométrico em fluxo desenvolvido no mestrado para análise de sulfito e HMS em água de chuva. Assim, desenvolveu-se três sistemas FIA-Amperométrico com eletrodo de gota pendente de mercúrio distintos, os quais foram utilizados para determinação de HSO3- livre e adutado (na forma de hidroxialcanossulfonatos) e SO2, com auxílio de uma unidade de difusão gasosa. / Alongside with its main components, the atmosphere contains trace amounts of thousands of chemical compounds (organic and inorganic) distributed in the liquid and gaseous phases, as well as in the particulate matter. These species can be considered pollutants when they are encountered at levels capable of generating adverse effects to humans, animals, plants or materials. The aim of this work was to establish alternative, efficient and practical methods for the sampling of several species encountered in the gaseous phase, as well as to develop analytical methods based on electroanalytical flow techniques, such as amperometry and capillary electrophoresis with contactless conductometric detection (CE-CCD). Due to some limitations in the existing sampling techniques, an altemative method based on the diffusion of the analytes through the microporous hydrophobic walls of capillary tube filled with an appropriate absorbent solution, was investigated. The collecting device was assembled using a Teflon® tube wherein a bundle of porous capillary polypropylene tubes was introduced. The coupling of this sampling technique with the selective and quantitative determination of the species by capillary electrophoresis with contactless conductometric detection (CE-CCD) enabled the development of complete analytical protocols for the following species: i) CH2O - collected in deionized water at a frequency of 1 sample/h and derivatized with HSO3- for its determination as hydroxymethanesulfonate (HMS); ii) HCOOH and H3COOH - collected using the same sampling procedure and quantified upon separation by CE-CCD; and iii) NH3 - collected in a HCl solution and deterrnined as NH4+ form. Another species of environmental interest is H2O2, which contributes to the acidity of the atmosphere on account of its involvement in some oxidation process both in the gaseous and liquid phases. The deterrnination of the H2O2 Was carried out using a FIA amperometric method at the hanging mercury drop electrode, in a batch electrochemical cell adapted to function under tlowing conditions. Two sampling procedures for H2O2 in the gaseous phase were developed and compared: . collection by diffusion - from the air into a flow of deionized water within the bundle of capillary filaments, which were, in tum, connected to the sample loop in order to allow on-line deterrninations. · cryogenic, with a \"passive\" sampler - based on the well-known fact that the H2O:H2O2 ratio in the gaseous phase is practically maintained in the solid phase. In addition to these determinations in the gaseous phase and in a partnership with researchers of the IPEN, the FIA-Amperometric method was used for the quantification of H2O2 in effluent and in cultivation water of the microcrustacean Daphnia Similis after irradiation by MeV electron beams. In parallel to the related research, a methodology for the CE-CCD determination of majority cations and anions in rain water was developed. This was proposed as an altemarive method to well-established ion chromatography techniques. Initial studies on the ionic composition of rain were conducted on samples collected between April/97 and March/98, using an automatic collector previously developed. In this set of samples, the concentrations of cations (NH4+, Ca2+, K+ e Na+) and anions (NO3-, SO42- e Cl-) were determined, together with the usual measurements of pH and conductivity. Capillary electrophoresis tumed out to be particularly suitable for the determination of ions in rain water. Although strictly not environrnental in kind, a methodology for determination of S(IV) species in wine samples was implemented by adjusting a previously-developed flow-amperometric method for the analysis of sulfite and HMS in rain water. For this purpose, three distinct FIA-Amperometric systems using a gas diffusion device and the hanging mercury drop electrode were designed, assembled and used for the determination of HSO3- in the free and bound forms (as hydroxyaIkanesulfonates) and SO2.

The normal operation of the endocrine (hormonal) system can be disrupted by a number of man-made and naturally-occurring chemicals, thereby affecting those physiological processes that are under hormonal control. Such substances are called endocrine disrupting compounds (EDCs). The endocrine disruption issue has alarmed the environmental authorities since the substances involved can hinder hormonal processes causing far-reaching effects on reproduction and development in current and future human and wildlife generations. Effects on some species of fish triggered worldwide concern and initiated a research scheme which is being undertaken by various organisations e.g. United States Environmental Protection Agency (USEPA), United Kingdom Environment Agency (UKEA), Oslo and Paris Commission (OSPAR), Japan Environment Agency (JEA) and World Wildlife Fund (WWF) in order to assess the effects (present and potential), point of generation, levels of contamination and exposure limits. The findings showed that most of the oestrogens are produced by humans and animals and get discharged into river streams mainly through sewage effluents. Fish in particular have been found to be affected the most even when the oestrogenic levels in water are very low. The probability of future European legislation to eliminate hormonally active compounds from wastewaters suggests that new and alternative methods should be developed for their removal. In this work, the adsorption of 17ß-oestradiol (E2) and 17a-ethinyl oestradiol (EE2) onto several granular activated carbons and Hypersol-Macronet hypercrosslinked polymers was investigated by batch experiments after a low level detection system had been developed using Gas Chromatography Mass Spectrometry (GC/MS). Equilibrium experiments were carried out for all adsorbents to quantify the sorption capacity for E2 and EE2. For better assessment of the sorbents performance, their physical properties such as surface area, average pore diameter and micropore volume and chemical structure were characterised by N2 adsorption experiments, scanning electron microscopy (SEM), FTIR spectroscopy, elemental analysis, sodium capacity determination, pH titration, proton binding curves and zeta potential measurements. Adsorption isotherm data were fitted to the Langmuir and Freundlich equations. Activated carbons were found to be preferable to Hypersol-Macronet hypercrosslinked polymers for adsorption purposes. The adsorption of oestrogens appears to be controlled by hydrophobic interactions. Kinetic experiments were performed with different size ranges of adsorbents at different concentrations and the results were analysed by a particle diffusion model. It was found that concentration did not seem to influence the kinetics of the oestrogen sorption whereas the particle size of the adsorbents influenced the adsorption rate of both molecules. The particle diffusion model seemed to fit the data collected for the adsorption rate of 17B-oestradiool onto the adsorbents but gave a poor fit for most of the data collected for 17a-ethinyl oestradiol.

Cyanobacterial blooms and their toxins are a major water quality and potential health risk around the world. This thesis developed an analytical method for microcystin congeners in sediments in order to examine their fate in lakes and establish the history of toxin-producing cyanobacteria in relation to environmental change using lake sediments. A novel method for both intra- and extracellular microcystins in lake sediments was developed, consisting of accelerated solvent extraction, hydrophilic-lipophilic balance solid phase extraction and multiple reaction monitoring-based HPLC-MS/MS quantitation. The method achieved comparable recoveries of intra- and extracellular cyanotoxins based on nine microcystins and nodularin (marine analogue). The analytical method was validated using surficial and deeper sediments from seven lakes of diverse geography and trophic state. To study the fate of microcystins, a multi-year, whole lake study of Microcystis blooms was conducted to obtain both in situ and in vitro half-life estimates of microcystin-LA (MC-LA), an understudied, but increasingly reported microcystin. MC-LA appeared to undergo slower rates of decomposition and persist longer than the more frequently studied MC-LR. Experimentally, high light intensity increased in vitro decomposition of dissolved MC-LA while high temperature enhanced decomposition in the particulate phase. Sediment deposition measurements and estimates of sediment-pore water distribution coefficients, sediment accumulation rates, and diffusive fluxes indicated that microcystin congeners differ in their fate. Notably, MC-LA preferentially distributed into pore water and remobilized (by diffusion) from sediments and into overlying water while MC-RR adsorbed more strongly to sediment particles. Finally, the sediment record of an eutrophic lake of major recreational importance was examined to identify possible drivers of toxigenic cyanobacteria and determine if the perceived increase in toxigenic cyanobacteria could be corroborated. Microcystins were detected to the bottom of the core (early 1800s), indicating that toxigenic cyanobacteria were present prior to the first permanent settlements. Microcystins were significantly correlated with changes in diatom-inferred nutrients (DI-TP and DI-TKN) within the sediment core as well as with specific algal pigments. Sediment microcystins in the upper layers also significantly correlated with a 20-year monitoring record for water column microcystins suggesting that sediment microcystins can be used as a proxy for past surface water conditions.

Sulphur stable isotope ratios are useful tracers in geological and environmental studies. They can for example be used to trace the origin of atmospheric sulphate aerosols, because anthropogenic sulphate and natural sulphate have distinguishable δ34S-values (δ34S value of approximately +0 to +8 ‰ for anthropogenic and approximately +12 to +19 ‰ for natural). This is useful for climate modelling research, due to the net cooling effect of aerosol sulphate. In the present study a Nu Plasma II (Nu Instruments) multi collector inductively coupled plasma mass spectrometer (MC-ICP-MS) method for measuring stable sulphur isotope ratios in low sulphur content samples, such as sulphate aerosols, was developed. The method was then applied to a sulphate aerosol sample collected in the Maldives.Most of the measurements were performed at high resolution, due to the interferences on 33S. Heated spray chamber coupled to a desolvating membrane, Aridus II (Cetac), increased the sensitivity and reduced interferences notably compared to wet plasma mode. Aridus II gave more stable measurements than DSN-100 (Nu Instruments). Determinations of δ34S for IAEA S1, S3, and S4 were accurate and the determined δ34S-value of the CIT #39 seawater standard (21.05 ± 0.36 ‰, 2SD, n=42) was comparable with published data. In general, Si internal standardization correction increased precision ~2.5 times compared to non-corrected values. The δ34S-value for the sulphate aerosol sample was determined to 3.82 ±0.41 ‰ (2SD, n=40). Repeatability of ~62 nmol introduced sulphur (2 μg/mL) was generally 0.15 ‰ (2SD, n=5) for the SW and 0.19 ‰ (2SD, n=5) for the sulphate aerosol sample. Comparable results for the SW (20.61±0.09 ‰, 2SD, n=4) and sulphate aersosol sample (3.77 ± 0.08 ‰, 2SD, n=8) were obtained with the method applied to Neptune Plus (Thermo Fischer Scientific) MC-ICP-MS in a different laboratory. The determined aerosol sulphate δ34S-value indicated that the sampled sulphate aerosol originated from anthropogenic sources.

Les matériaux corrélés offrent une richesse de nouveaux phénomènes, dont beaucoup ne sont pas encore - ou seulement partiellement - compris. Au centre de cette thèse sont des modèles multi-orbitalaires que j'etudie à travers une palette de méthodes, dont la théorie du champ moyen dynamique. Dans le modèle de Hubbard multi-orbitalaire proche de la transition de Mott, je mets en évidence un régime de mauvais métal induit par le couplage de Hund. Les propriétés de la transition de Mott dans ce système sont analysées. Dans un deuxèime temps, je traite un modèle élargi pour inclure des degrés de liberté des ligands dans les oxydes. Plus spécifiquement, cette thèse étudie les effets des interactions inter-couches entre orbitales corrélés d'un atome de métal de transition et les orbitales p des ligands. Une partie du travail est dédiée au développement de nouvelles méthodes dont une approche de rotateurs esclaves à ce problème. Le dernier chapitre concerne le domaine de la spintronique moléculaire, où j'étudie la physique du "spin-state switching" en fonction de l'hybridation d'un ion de métal de transition avec ses ligands dans les molecules organométalliques du type porphyrine de nickel. / The physics of correlated materials offers a wealth of new phenomena, many of which are not yet - or only partially - understood. In this thesis, we focus on multi-orbital models, which we study using various methods, including dynamical mean-field theory. We show that in the multi-orbital Hubbard model close to the Mott transition, Hund's coupling gives rise to a bad metal regime the properties of which we analyze. Furthermore, we consider a more general class of models that include oxygen ligands. More specifically, we study the effect of inter-shell interactions between correlated metal- and ligand p-orbitals. In this context, we develop and test a new slave-rotor approach to treat such interactions in an effective manner. The final chapter constitutes an excursion to the field of molecular spintronics, where we study the physics of the hybridization-induced spin-state switching in organometallic nickel porphyrin molecules.

Peptides are used as synthetically available and easily derivatizable scaffold upon which it is possible to develop ligands targeting broad spectrum of biological targets. A time-tested approach to peptide binder identification is the preparation and screening of combinatorial libraries. Bypassing of this complicated procedure is possible by using biological systems for presentation, identification and selection of peptides based on the principle of in vitro evolution - i.e. display techniques. There are two complementary automated solutions for peptide binder identification described in this work. First is the SPENSER parallel peptide synthesizer, developed as a part of this diploma project, which can be used for peptide ligand discovery and optimization as well as validation of ligands identified using display techniques. Several libraries consisting of a total of 1 052 peptides have been prepared and then used to describe its potential applications. A sample of 154 preparations, representing 14.6 % analytical coverage of the prepared libraries, showed an average purity of 67 ± 19 % according to LC-MS. The libraries presented illustrate that SPENSER is a suitable tool for the parallel synthesis of linear and disulfide-cyclized peptides with limited variability, or libraries consisting of short...

No description available.

The purpose of this thesis work was to develop a headspace solid phase microextraction gas chromatography mass spectrometry (HS-SPME-GC-MS) method to detect volatile organic compounds (VOCs) in board samples and to statistically investigate potential correlation between chromatographic data and flavor data obtained from a trained panel. The developed method would hopefully serve as a complement to the already established routine analyses at Stora Enso and gain an increased understanding of which VOCs in the board influence its flavor properties. The impact of incubation time and adsorption time on the area under curve (AUC) was studied with a Design of Experiment screening using the software MODDE. The screening data showed a correlation between large AUC and low repeatability measured as relative standard deviation (RSD). The data was hard to fit to a model due to the large RSD values for the replicates, AUC for identified compounds as response gave an acceptable fit. The regression coefficients for the model showed that a longer adsorption time gave larger AUC, while incubation time had no significant impact on the response.  Instead of following up the screening with an optimization, the focus was shifted to improving the repeatability of the method, i.e. lowering the RSD. The high RSD was believed to mainly be the result of leakage of analytes and unstable temperature during adsorption, preventing the system from reaching equilibrium. Different heating options and capping options for the vial was tested. Septum in crimp cap ensured a gas tight seal for the vial, giving lower RSD values and larger AUC compared to the other alternatives, showing that there was indeed a leakage. Using oil bath ensured stable temperature during the adsorption and detection of a larger number of VOCs but created a temperature gradient in the vial due to it not being fully submerged in the oil. Oil bath gave larger AUC, but still high RSD due to the temperature gradient making the method sensitive to variance in fiber depth in the vial. The final method was performed with 2 g of board sample in a 20 ml headspace vial sealed with a crimp cap with septa. The incubation and adsorption were performed with the vial immersed in a 90-degree oil bath. 20 min incubation time was chosen based on the time it took to get a stable temperature gradient in the vial, and 20 minutes adsorption time was chosen as a good compromise between large AUC and low RSD. Compared to Stora Ensos routine analysis, the developed SPME method gave chromatograms with an improved signal-to-noise ratio for the base line and several more peaks with larger AUC. For the board sample used during method development, the SPME-method identified 34 VOCs, while the routine analysis only identified 12. The developed method was applied on 11 archived board samples of the same quality that were selected based on their original flavor properties, to get a large diversity of samples. Flavor analysis was performed by letting a trained flavor panel describe the flavor based on intensity and character of the water that had individually been in indirect contact with one of the 11 board sample for 24 h. Potential correlation between chromatographic data obtained with the developed method and the flavor experience described by the flavor panelists was statistically investigated with the multivariate analysis software SIMCA. The correlation study showed that a combination of 12 VOCs with short retention time are most likely the main source of off-flavor which of 5 could only be identified with the developed SPME method. VOCs with long retention time did not contribute to an off-flavor and might have a masking effect on flavor given by other VOCS, however not confirmed in this study. Furthermore, the age of the board samples proved to be a good indicator for prediction of the flavor intensity, whereas the total AUC of the samples was not. Possible correlation between detected VOCs in the samples and flavor character given by the flavor panel were seen, however the variation in the data and the sample set were too small, preventing from making conclusions on individual VOCs impact on the flavor experience. The developed HS-SPME-GC-MS method would serve as a complement to the already established routine analyses at Stora Enso and has slightly increased the understanding of which VOCs in the board influence the flavor properties

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Vanliga fenoliska antioxidanter som används i polymerer orsakar färgändringar i polymeren. Detta arbete berör antioxidanter med jämförelsevis begränsad färgändring, med fokus på att utveckla metoder för analys av dessa. UV-stabilisatorerna UV2, UV5, UV1, UV4, UV3 och UV6 är också inkluderade i detta arbete. Metodutvecklingen involverade både kapillärelektrofores och ”matrix assisted laser desorption ionization-time of flight mass spectrometry” (MALDI-TOF). Den bästa metoden för analys av de flesta av additiven inkluderade MALDI-TOF med 2’,6’-dihydroxyacetophenon (10 mg/ml) i TA50 som matris och hexafluoroisopropanol som lösningsmedel. När en metod för detektion av analyterna hade tagits fram, så inleddes utveckling av en metod för extraktion av additiv från polymera material. Extraktion av UV5 var framgångsrik vid användning av toluen vid 80 °C i ultraljudsbad i tre timmar. Det extraherade UV5 detekterades sedan med metoden som hade utvecklats för det rena additivet. / Ordinary phenolic antioxidants used in polymers give rise to color formations. This work concerns antioxidants with limited color-formations in comparison, with the focus being development of methods for analysis of these. Also included in this work are the high molecular weight UV-stabilizers UV2, UV5, UV1, UV4, UV3 and UV6. The method development involved both capillary electrophoresis and matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF). The best method for analysis of most additives involved using MALDI-TOF with a matrix consisting of 2’,6’-dihydroxyacetophenone (10 mg/ml) in TA50 and with hexafluoro isopropanol as the solvent. When a method for detection of the analytes had been obtained, a method for extraction of the additives from polymers was developed. UV5 was successfully extracted using toluene as the extracting solvent at 80 °C under sonication for three hours. The extracted UV5 was then detected using the method developed for the pure additive.