Les déchets solides générés par notre société sont nombreux. Les cendres volantes sont des déchets solides produits lors de la combustion de déchets domestiques ou industriels dans des incinérateurs. Les cendres volantes sont également produites par la combustion du charbon dans les centrales à charbon. Les cendres volantes sont des résultats de ces combustions et représentent importante quantité de déchets produits chaque année par notre société. Les possibilités de recyclage de ces déchets sont nombreuses : dans la construction, l'industrie routière. Elles sont également stockées pour une utilisation ultérieure. Les origines différentes des charbons et déchets incinérés conduisent à une minéralogie et une composition élémentaire complexe. En tant que sous-produit le devenir des cendres volantes est important à déterminer, aussi la détermination de la composition élémentaire de ces cendres volantes est-elle indispensable.Les méthodes classiques de préparation des échantillons solides sont la minéralisation acide ou la fusion alcaline. Ces procédures prennent du temps et supposent l’utilisation de réactif, de plus la digestion complète n'est pas toujours assurée. Le risque de contamination par les réactifs employés est important au cours de ces méthodes classiques de préparation. Au cours de la dernière décennie, le développement d’analyse directe d'échantillons solides en utilisant des méthodes d'ablation laser a été important en raison de la nécessité de réduire le temps d'analyse et de réduire aussi la consommation de réactifs. Dans ce travail, deux méthodes basées sur l'ablation par laser seront étudiées pour l'analyse des cendres: Laser Induced Breakdown Spectroscopy (LIBS) et Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). La spectrométrie LIBS sera étudiée pour la détermination quantitative des éléments majeurs dans les échantillons de cendres alors que le couplage ablation laser ICP / MS sera employé pour détermination des éléments traces. L'optimisation de la sensibilité et les stratégies d'étalonnage sont les principaux problèmes traités dans ce travail. La préparation des échantillons et l’optimisation ont été effectuées pour déterminer les éléments tels que Al, As, Ba, Ca, Cr, Cu, Fe, Mg, Mn, Pb, Sr, V et Zn par les deux méthodes.Les performances analytiques telles que les limites de détection, justesse ont été obtenus à la suite d'optimisations appropriées des liants et de la sélection de l’étalon interne approprié. En conclusion, l’analyse directe de solides en utilisant les techniques basées sur l’ablation laser développées dans ce travail conduisent à une justesse acceptable pour la détermination des éléments majeurs et traces dans les cendres volantes / Solid waste generated by our society are numerous, fly ashes are produced during the combustion of domestic or industrial waste in incinerators. Fly ashes are also produced through coal combustion in coal fired power plants. Fly ashes are results of these combustions and represent important quantity of waste produced every year by our society. They have variable use – in construction, road industry, or they can be stocked for further use. As they are result of different origin, they have complex mineral and elemental composition. As a by-product or as a recycled product fly ashes fate is important to determine. In this view the determination of the elemental composition of fly ashes is the aim of this work.Conventional methods of sample preparation are acid digestion or alkali fusion. These procedures are time and reagent consuming and complete digestion is not assured. The potential contamination of the reagents employed is important during these classical sample preparation methods. During the past decade, development of direct solid sampling using laser ablation methods was important due to the need of reducing analysis time and also reducing reagent consumption. In this work, two methods based on laser ablation will be studied for fly ash analysis: Laser Induced Breakdown Spectroscopy (LIBS) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). LIBS will be studied for quantitative determination of major elements in fly ash samples while Laser ablation / ICP MS will be employed for trace element determination.The sensitivity optimization and different calibration strategies are key problems of laser sampling methods. Sample preparation and condition optimisation were performed to determine major, minor and trace elements such as Al, As, Ba, Ca, Cr, Cu, Fe, Mg, Mn, Pb, Sr, V and Zn by both methods – LIBS for major elements and LA-ICP-MS for minor and trace elements.Analytical properties such as detection limits, accuracy and analytical working curves were obtained following suitable optimisation of binders and internal standards. Compromise binder and analytical conditions were selected to determine the elements in fly ash samples.In conclusion, direct solid sampling using laser ablation followed by LIBS or for solid introduction into ICP was found to determine major, minor and trace elements in fly ashes, improving pellets mechanical stability, high samples sensitivity and acceptable accuracy and detection limits.

Thesis (MSc)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: The determination of the platinum group metals (PGMs), platinum, palladium, rhodium, iridium, ruthenium and osmium, remains a problem for the low-grade ore samples, and the analysis of these samples in a routine laboratory relies entirely on the fire assay technique. The use of large sample masses to overcome sub-sampling errors has been the greatest advantage of this technique. The increased economic value of PGMs and recent developments in instrumentation such as inductively coupled plasma-mass spectrometry (ICP-MS) which is capable of trace element detection as low as part per billion (Ppb) levels, have led to a search for complementary methods to ensure the accuracy of fire assay results. This work investigates the feasibility of direct dissolution of ore samples using microwave-assisted dissolution followed by ICP-MS as the measurement technique. Due to the limited sample mass that can be used, a thorough consideration had to be given to sampling errors and analytical errors to assess the overall precision achievable. Most PGM-bearing minerals occur as sulphides and these are highly resistant to acid dissolution. It was found that roasting the Merensky type samples in air, prior to dissolution gives quantitative recoveries for platinum. Recoveries up to 100% were obtained for platinum, palladium, rhodium and gold for a Merensky flotation concentrate with excellent precision (about 4%) except for gold which had poorer precision (16%). However, ore samples presented a problem due to their lower PGM content and smaller sample masses being used. Precision for all elements improved significantly (from about 20% to about 8%), with the use of l g-sample aliquot compared to that ofO.25 g-sample. Acid dissolution, even after roasting proved to be insufficient for the UG-2 chromitite samples. When roasting was followed with reduction under hydrogen flame the solubility of the UG-2 flotation concentrate improved remarkably. The recoveries obtained were approximately 95 ± 5% for platinum, 99 ± 5% palladium, 104 ± 12% gold and 102 ± 5% for rhodium with good precision (comparable to that of Merensky concentrate). The accuracy and precision of the results depended very much on the sample mass and air-flow in the furnace during the roasting procedure. For this method to be used successfully, the air flow is very critical, and should lead to a better furnace design which can rotate the crucibles to enable an even flow of air over all the samples during roasting. / AFRIKAANSE OPSOMMING: Die bepaling van platinumgroep metale (PGM'e), platinum, palladium, rhodium, iridium, ruthenium en osmium is 'n voortdurende probleem vir die lae-graad erts monsters. Die analise van hierdie monsters in 'n roetine laboratorium is geheel afhanklik van die klassieke "fire assay"-tegnieke. Die groot voordeel van hierdie tegniek is die voorkoming van monsternemingsfoute deur die gebruik van groter monster massas. Die ekonomiese waarde van PGM'e saam met die onlangse ontwikkeling van instrumentasie soos die induktief-gekoppelde plasma-massaspektrometrie (IGP-MS) wat in staat is om spoorelemente in konsentrasies so laag soos dele per biljoen (ppb) te meet, het daartoe gelei na soeke vir komplementêre metodes om die akkuraatheid van klassieke "fire assay" -tegnieke te verseker. Hierdie werk ondersoek die waarskynlikheid van direkte oplossing van ertsmonsters deur gebruik te maak van mikrogolf-ondersteunde oplossing gevolg deur IGP-MS as opmetingstegniek. As gevolg van die beperkte monster massa wat gebruik kan word, moes deeglike oorweging gegee word aan monsternemingsfoute en analitiese foute, om die oorkoepelende presiesheid te bepaal. Meeste PGM-draende minerale bestaan in die vorm van sulfiede en bied groot weerstand teen oplossing in 'n suur. Die gloei van Merensky-tipe monsters in lug voor oplossing gee kwantitatiewe herwinning van platinum Herwinning tot 100% is behaal vir platinum, palladium, rhodium en goud vir 'n Merensky-flotasie-konsentraat met uitstekende akkuraatheid (4%) behalwe vir goud met 'n swak (16%) akkuraatheid. Die erts monsters was problematies as gevolg van die laer PGM inhoud en kleiner monstermassas wat gebruik is. Presiesheid vir al die elemente het beduidend verbeter (van 20% tot 8%) met die gebruik van 1 g- monster massas vergelyk met 0.25 g-monsters. Ten spyte van die gloei van die monster is suur oplossing onvoldoende vir die UG-2 chromatiet-houdende monsters. Wanneer die monster gegloei is onder 'n waterstof vlam (reduksie) het die oplossbaarheid van UG-2 flotasie-konsentraat aansienlik verbeter. Die herwinbaarheid wat behaal is, is 95 +/- 5% vir platinum, 99 +/- 5% vir palladium, 104 +/- 12% vir goud en 102 +/- 5% rhodium met goeie relatiewe presiesheid vergeleke met Merensky-konsentrate. Die akkuraatheid en presiesheid van resultate hang meerendeels af van monster massa en lugvloei in die oond gedurende gloei. Die lugvloei is krities vir die sukses van hierdie metode en sal moet lei tot beter oond ontwerp wat kroesies kan roteer en 'n gelyke vloei van lug oor die monsters gedurende verbranding toelaat.

L’objectif de cette thèse était la modélisation numérique de la torche à plasma à couplage inductive. (ICP). Nous avons établi les bases de données nécessaires : composition, propriétés thermodynamiques et de transport appliqués aux mélanges d’argon, d’acide nitrique et d’eau. Le modèle hydrodynamique de la torche ICP (7 spires) considère le plasma à l'équilibre thermodynamique et couple les équations de Navier-Stokes pour décrire l'écoulement du plasma aux équations de Maxwell pour décrire l'évolution du champ électrique et du champ magnétique. / The purpose of the work was the numerical modeling of the inductive coupling plasma torch. (ICP). We have established the necessary databases: composition, thermodynamic and transport properties applied to argon mixtures of nitric acid and water. The hydrodynamic model of the ICP torch (7 coils) considers the plasma at thermodynamic equilibrium and uses the Navier-Stokes equations to describe the plasma flow and the Maxwell equations to describe the evolution of the electric field and the magnetic field.

M.Sc. / The origin of a wine plays a key role in establishing the quality and the price the consumer is prepared to pay. Fingerprinting techniques based on multi-element data combined with multivariate statistical analysis as well as isotope ratio data for certain elements such as boron (11B/10B) and strontium (87Sr/86Sr) are being developed and have been used for provenance determination of wine with varying degrees of success. The aim of this study was to develop a method to determine boron isotope ratios (11B/10B) with the required precision using ICP-MS (inductively coupled plasma mass spectrometry) in soil and wine samples and applying this method to establish the origin of South African wines. Analytical difficulties such as the boron memory effect, dead time, mass bias drift and matrix effects were investigated. Although the memory effect, dead time and mass bias drift were satisfactorily resolved, it was not possible to determine what the cause of all the observed matrix effects was during this study. The method was used to categorise wines from the Robertson, Swartland and Stellenbosch regions and an attempt was made to link the measured boron isotope ratios with that obtained from the corresponding provenance soils. The 11B/10B isotope ratios for the wine samples (Robertson: 4.202 ± 0.014, Swartland: 4.173 ± 0.013 and Stellenbosch: 4.174 ± 0.028) were, however, higher than the ratios obtained for the soil samples (Robertson: 4.108 ± 0.020, Swartland: 4.070 ± 0.023 and Stellenbosch: 4.124 ± 0.039). It was possible to distinguish, using the boron isotope ratios (wine and soil samples), between the Robertson area (Breede River region) and the Swartland area (Coastal region). The wine and soil 11B/10B isotope ratios obtained for the Stellenbosch area (Coastal region) overlapped with the 11B/10B isotope ratios of the Robertson and Swartland regions making it impossible to differentiate it from these two regions.

Magister Scientiae (Medical Bioscience) - MSc(MBS) / Mercury (Hg) is an example of a toxic metal that is not essential for nutrition. It exists in organic and inorganic forms in seafood and vapour from dental amalgam fillings respectively. Elemental mercury (Hg0) from dental amalgam was the focus of this study. Dental amalgam is one of the most commonly used dental filling materials and has been used for over 150 years. It is composed of Hg0 (approximately 50%) combined with other metals such as copper and zinc (Zn). These fillings give off Hg0 vapour throughout their existence, and is further enhanced by activities such as chewing, grinding of teeth and drinking hot liquids. Mercury consumption can lead to Zn loss or deficiency, and is reported to displace Zn and copper. Several European nations have outlawed the use of amalgam as a restorative material due to controversies regarding its safety in children, women of childbearing age and individuals with renal disease. Moreover, various studies have reported correlations between the number of amalgam fillings and Hg concentration in blood plasma, urine, faeces, saliva and different organs. Blood, urine, and hair mercury levels are used to predict possible health effects that may be caused by the different forms of Hg. Urine Hg is used to test exposure to metallic Hg0 vapour and inorganic Hg forms. This study aimed to evaluate the effects of Hg0 from dental amalgam restorations on the status of Zn in the urine. This was done by determining the concentrations of Hg0 in urine, buccal cells and the oral cavity, and its relationship with urinary Zn concentrations in the same individuals. Samples of urine, buccal tissues, chewing gum and completed questionnaires were collected from the participants (women and men) at the dental clinics in Tygerberg Hospital (TBH), Cape Town. Samples were analyzed using inductively coupled plasma mass spectrometer (ICP-MS). Findings from this study show that there was a correlation between levels of urinary Hg0 and urinary Zn (p=0.02). However, urinary Hg0 did not predict the amount of urinary Zn. Also, no relationship was found between levels of Hg0 in buccal swab or the chew test samples and urinary Zn level. There was a significant difference between females and males in the level of urinary Zn, men had higher levels of Zn excreted in the urine than females (p=0.05). However, there was no significant difference in the level of urinary Hg0 between males and females. The number of fillings (4-7) and age of fillings were significantly associated with urinary Hg0 level (p˂0.05), while smoking ˃15 cigarettes/day increased the level of Hg0 in buccal swab samples (p=0.002). We were not able to demonstrate a causal effect of Hg0 leaching on urinary zinc levels.

The primary aim of this thesis is to develop image processing algorithms to quantitatively determine the link between traumatic brain injury (TBI) severity and chronic traumatic encephalopathy (CTE) neuropathology, specifically looking into the role of blood-brain barrier disruption following TBI. In order to causally investigate the relationship between the tau protein neurodegenerative disease CTE and TBI, mouse models of blast neurotrauma (BNT) and impact neurotrauma (INT) are investigated. First, a high-speed video tracking algorithm is developed based on K-means clustering, active contours and Kalman filtering to comparatively study the head kinematics in blast and impact experiments. Then, to compare BNT and INT neuropathology, methods for quantitative analysis of macroscopic optical images and fluorescent images are described. The secondary aim of this thesis focuses on developing methods for a novel application of metallomic imaging mass spectrometry (MIMS) to biological tissue. Unlike traditional modalities used to assess neuropathology, that suffer from limited sensitivity and analytical capacity, MIMS uses a mass spectrometer -- an analytical instrument for measuring elements and isotopes with high dynamic range, sensitivity and specificity -- as the imaging sensor to generate spatial maps with spectral (vector-valued) data per pixel. Given the vector nature of MIMS data, a unique end-to-end processing pipeline is designed to support data acquisition, visualization and interpretation. A novel multi-modal and multi-channel image registration (MMMCIR) method using multi-variate mutual information as a similarity metric is developed in order to establish correspondence between two images of arbitrary modality. The MMMCIR method is then used to automatically segment MIMS images of the mouse brain and systematically evaluate the levels of relevant elements and isotopes after experimental closed-head impact injury on the impact side (ipsilateral) and opposing side (contralateral) of the brain. This method quantifiably confirms observed differences in gadolinium levels for a cohort of images. Finally, MIMS images of human lacrimal sac biopsy samples are used for preliminary clinicopathological assessments, supporting the utility of the unique insights MIMS provides by correlating areas of inflammation to areas of elevated toxic metals. The image processing methods developed in this work demonstrate the significant capabilities of MIMS and its role in enhancing our understanding of the underlying pathological mechanisms of TBI and other medical conditions. / 2019-07-09T00:00:00Z

Chan Sze-Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 65-73). / Abstracts in English and Chinese. / Acknowledgment --- p.i / Table of Contents --- p.ii / Abstract --- p.v / Abstract (Chinese Version) --- p.vi / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Molybdenum in the Environment --- p.1 / Chapter 1.1.1 --- General Chemistry of Molybdenum --- p.1 / Chapter 1.1.2 --- Molybdenum in Animals and Plants --- p.1 / Chapter 1.1.3 --- Uses of Molybdenum Compounds --- p.3 / Chapter 1.2 --- Inductively Coupled Plasma Atomic Emission Spectrometry --- p.4 / Chapter 1.2.1 --- Principle of ICP-AES --- p.4 / Chapter 1.2.2 --- Inductively Coupled Plasma Emission Source --- p.5 / Chapter 1.2.3 --- Optical System --- p.6 / Chapter 1.2.4 --- Advantages of ICP-AES --- p.7 / Chapter 1.2.5 --- Disadvantages of ICP-AES --- p.8 / Chapter 1.3 --- Preconcentration Method --- p.9 / Chapter 1.4 --- Polysiloxane --- p.11 / Chapter 1.4.1 --- Introduction of Silica-gel --- p.11 / Chapter 1.4.2 --- Introduction of Sol-gel Processes --- p.13 / Chapter 1.4.3 --- Hybrid Inorganic-organic Sol-gel Materials --- p.14 / Chapter 1.4.4 --- Advantages Using Sol-gel Preparation of Organomodified Silica --- p.16 / Chapter 1.5 --- Chelating Resin --- p.19 / Chapter 1.6 --- Scope of Work --- p.21 / Chapter Chapter 2 --- Experimental --- p.22 / Chapter 2.1 --- Apparatus and Instrument --- p.22 / Chapter 2.2 --- Chemicals --- p.24 / Chapter 2.3 --- Samples --- p.25 / Chapter 2.4 --- Procedures --- p.26 / Chapter 2.4.1 --- Preparation of Diethylenetriaminetetraacetic-acid Functionalized Polysiloxane --- p.26 / Chapter 2.4.1.1 --- Preparation of Silica Precursor --- p.26 / Chapter 2.4.1.2 --- Functionalization with Diethylenetriamine --- p.27 / Chapter 2.4.1.3 --- Carboxymethylation of the amine groups of the Polysiloxane --- p.28 / Chapter 2.4.2 --- Preconcentration and Determination of Molybdenum --- p.29 / Chapter 2.4.2.1 --- Optimum pH for Adsorption --- p.29 / Chapter 2.4.2.2 --- Amount of Polysiloxane Required for Sorption of Trace Amount of Molybdenum --- p.29 / Chapter 2.4.2.3 --- Equilibrium Time --- p.30 / Chapter 2.4.2.4 --- Total Adsorption Capacity --- p.30 / Chapter 2.4.2.5 --- Adsorption Isotherm of Molybdenum --- p.30 / Chapter 2.4.2.6 --- Desorption Studies --- p.31 / Chapter 2.4.2.7 --- Effect of Foreign Ions on Preconcentration --- p.31 / Chapter 2.4.2.8 --- Preparation of the Mini-column --- p.32 / Chapter 2.4.2.9 --- Effect of Flow Rate --- p.33 / Chapter 2.4.2.10 --- Reusability of the Mini-column --- p.33 / Chapter 2.4.2.11 --- Preconcentration Factor and Detection Limit --- p.33 / Chapter 2.4.2.12 --- Determination of Mo(VI) in Seawater by ICP-AES --- p.33 / Chapter Chapter 3 --- Results and Discussion --- p.35 / Chapter 3.1 --- Characterization of Diethylenetriaminetetraacetic-acid Functionalized Polysiloxane --- p.35 / Chapter 3.2 --- pH Dependence of Mo(VI) Ion Uptake --- p.44 / Chapter 3.3 --- Amount of Polysiloxane Required for Adsorption of Trace Amount of Mo(VI) --- p.45 / Chapter 3.4 --- Equilibrium Time --- p.46 / Chapter 3.5 --- Total Adsorption Capacity --- p.47 / Chapter 3.6 --- Adsorption Isotherm of Molybdenum --- p.48 / Chapter 3.7 --- Desorption Studies --- p.54 / Chapter 3.8 --- Effect of Foreign Ions on Preconcentration --- p.55 / Chapter 3.9 --- Effect of Flow Rate on the Recovery of Mo(VI) --- p.57 / Chapter 3.10 --- Reusability of the Column --- p.58 / Chapter 3.11 --- Preconcentration Factor --- p.59 / Chapter 3.12 --- Detection Limit --- p.59 / Chapter 3.13 --- Accuracy --- p.60 / Chapter 3.14 --- Determination of Mo(VI) in Seawater Samples --- p.61 / Chapter 3.15 --- Precision --- p.62 / Chapter Chapter 4 --- Conclusion --- p.63 / Chapter Chapter 5 --- References --- p.65

The Fäboliden gold deposit is an ore body in northern Sweden’s Bothnian Basin and has been the subject of studies and test mining since the early 2000s when the Gold Line, an area of anomalously high-Au glacial till in Northern Sweden, became a center of economic interest. The deposit is a hypozonal orogenic gold deposit that displays many characteristic features of ore bodies of this type, including the presence of compound sulfide grains composed of a core of löllingite surrounded by a rim of arsenopyrite, and an abundance of pyrrhotite throughout the deposit and surrounding alteration zone. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was used to first map the distribution of trace elements in several of the arsenpyrite-löllingite grains, then to perform spot analyses of pyrrhotite grains in samples from across the distal and proximal alteration zones of the deposit. The maps of the trace elements in the compound löllingite-arsenopyrite grains show that: As and Au are found in greater abundance in the löllingite than in the arsenopyrite; Cu, Fe, S, and Ti are found in greater abundance in the arsenopyrite than in the löllingite; and Ag, Au, Bi, La, Mn, Pb, Sr, Ti and Tl are found in zones of secondary enrichment along fractures within the grains. Uranium and V may also be enriched along fractures, although this isn’t clear on all of the maps. Gold is an element of particular interest, because its distribution throughout the sulfide phases can be used to constrain the mechanism and relative timing of mineralization within the deposit. The presence of invisible gold within the löllingite, but not within the arsenopyrite, shows that gold is not incorporated into arsenopyrite at high temperatures and will instead be concentrated in the löllingite core of the composite grain and at the margin between the two sulfide phases as the löllingite is altered to arsenopyrite. Previous research on the Fäboliden gold deposit, including geothermometric analysis of vein-hosted graphite within fluid inclusions and garnet-biotite geothermometry as well as structural evidence provided by regional deformation, indicate that mineralization occurred post-peak metamorphism. The textures seen are therefore not conclusive of mineralization occurring syn- or pre-peak metamorphism, as has previously been proposed based on research of orogenic gold deposits in Western Australia. The spot analysis of pyrrhotite samples from across the deposit shows a distinct decrease in Ni and Co content in the proximal alteration zone, suggesting uptake of these elements by other minerals such as the löllingite and arsenopyrite. Multiple analyses performed on single grains show local variation, but are insufficient to establish the presence or determine the character of growth zonation within pyrrhotite.

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Determination of Ca and P in foods and B, Si, P and S in steels by dynamic reaction cell inductively coupled plasma mass spectrometry