MSc (Chemistry / Department of Chemistry / In this study, three sampling sites (Tshipise thermal spring, Mphephu thermal spring and Siloam borehole) in Limpopo Province South Africa were considered for an investigation into the mineral composition of their water and soil samples. Tshipise and Mphephu thermal springs are well developed and located within tourist resorts. On the other hand, Siloam is a borehole on the grounds of a private household. The water is used for various domestic purposes such as laundry, general cleaning of the household and bathing. Water and soil samples from the three sites were collected once per week every week in February 2018. The sampling bottles were spiked with 1M HNO3 before sampling to keep any metal ions present in the water samples in solution. The soil and water samples were analysed for their chemical composition using X-ray fluorescence (XRF) and inductively coupled plasma mass spectrometry (ICP-MS) respectively. XRF analysis of the soil samples found many major oxides of which SiO2 made up 63.67%, 85.37% and 46.28% by mass of Tshipise, Mphephu and Siloam soil samples respectively. XRF analysis also showed the presence of dangerous levels of heavy metals such as As, Tl, Pb and V. The analysis of the water samples by ICP-MS found that Tshipise, Mphephu and Siloam mineral water were soft, soft-moderately hard and soft-hard respectively with regards to the water hardness scale according to the United States Geological Survey (USGS) and the Water Quality Association (WQA). Analysis of water samples also found the presence of As, Cd, Cr and V. Arsenic was found to occur at concentrations above the Maximum Allowable Concentration (MAC) set by the World Health Organisation (WHO) (10 μg L-1) for Tshipise, Mphephu and Siloam mineral water (13.63 μg L-1, 15.83 μg L-1 and 20.97 μg L-1 respectively). Water temperatures for the three sites ranged from 38°C (Siloam borehole) to 64°C (Tshipise thermal spring). The pH values were 7.25 (Siloam borehole), 7.40 (Mphephu thermal spring) and 8.67 (Tshipise thermal spring). Due to the presence of As, Tl, Pb, V, Cd and Cr, the mineral water from all three thermal springs is unsafe to consume as it would lead to serious negative health effects some of which are outlined in this study. / NRF

This diploma thesis is focused on the study of electrochemical generation volatile species of gold and silver. Two non-membrane electrolytic cells were constructed for electrochemical generation volatile species. These cells differ in the volume of electrode chamber. An atomic absorption spectrometry with quartz tube atomizer was used in most experiments. The equipment was performed in flow continuous mode. Experiments confirmed, that it is possible to use an atomic absorption spectrometry with quartz tube atomizer for generate volatile species of gold and silver by using two non-membrane electrolytic cells. The main part of this thesis was to find optimal conditions for the electrochemical generation of volatile species of gold and silver. These optimized parameters were: the cathode material, the type of electrolyte, the flow rate of the carrier gas, the generation current and the electrolyte flow rate. The calibration curves for both analytes were measured for both non-membrane electrolytic cells and the basic characteristics of the measurement were observed. Detection limit for electrochemical generation of gold was 1,61mg dm 3 and repeatability 3,93 %, detection limit for electrochemical generation of silver was 0,20 mg dm 3 and repeatability 7,33 %. Thanks to the experiments with a...

Die vorliegende Arbeit stellt die Ergebnisse der methodologischen Entwicklung räumlich aufgelöster Analyse mittels Scanning Laserablation-ICP-Massenspektrometrie dar. Eine neue Behandlung zur Quantifizierung transienter analytischer Signale wurde für die Wiederherstellung von Konzentrationsprofilen vorgeschlagen. Die Anwendung der entwickelten Modelle auf die räumlich aufgelöste Analyse mittels LA-ICP-MS ermöglicht verbesserten Informationsgewinn und lässt dadurch eine höhere räumliche Auflösung erreichen. Die Anwendbarkeit der LA-ICP-MS für die räumlich aufgelöste Bestimmung der Stöchiometrie in supraleitenden Borokarbiden wurde untersucht. Der Einfluss apparativer Größen auf das analytische Signal wurde aufgeklärt, um die Messbedingungen zu optimieren. Zusätzlich wurden Fraktionierungseffekte untersucht, um die Ursache und deren Auswirkung auf die Analyse supraleitender Borokarbiden zu erklären. / This work represents the results of the methodological development of spatially resolved analysis by scanning laser ablation ICP mass spectrometry. A new approach to the quantification of transient analytical signals was proposed to reveal the concentration profile. An application of the developed models on spatially resolved analysis by LA-ICP-MS allows to gain more information from experimental data and hence to achieve better spatial resolution. The applicability of LA-ICP-MS to the spatially resolved determination of the stoichiometry of superconducting borocarbides was investigated. The effect of experimental parameters on analytical signals was elucidated in order to optimize the experimental conditions. In addition, fractionation effects were investigated to identify the causes for fractionation and their influence on the analysis of superconducting borocarbides.

Nanopartiklar är partiklar med storlekar i området 1 till 100 nm, och som uppvisar nanospecifika egenskaper. Egenskaperna kan variera helt mellan olika typer av nanopartiklar, även bland partiklarna och deras respektive material i bulk format på grund av deras unika storlekar, former och strukturer. I denna studie har vi analyserat storlekarna och den kolloidal stabiliteten på tre nanopartiklar, Co, Y2O3, CeO2 i färskvatten och färskvatten med naturligt organiskt material med hjälp av sonifikation, NTA, AAS och ICP analys. Nanopartiklarna lät vara utsatta i lösningarna i upp till six timmar, där analys med hand av NTA skedde efter den nollte, första och sjätte timmen. Partiklarna uppvisade olika egenskaper, och alla tre partiklar varierade i storlek under experimentet. Kobalt hade tendensen att minska i storlek i bägge lösningar, medan storlekarna på yttrium- och cerium oxid tenderade att variera. För att främja vår förståelse av nanopartiklar, behövs fler studier för att få en full förståelse för de unika egenskaperna hos dessa partiklar. / Nanoparticles are particles with sizes in the range of 1 to 100 nm, which also have nanospecific properties. Their properties vary wildly between different types of nanoparticles, even among nanoparticles and their respective particles in bulk format heeding to their highly individual shapes, sizes and structures. In this study we analyzed the sizes and colloidal stability of three different nanoparticles, Co, Y2O3 and CeO2 in freshwater and freshwater with natural organic matter solutions using sonication, NTA-, AAS-, and ICP analysis. The nanoparticles were exposed to the solutions for up to six hours, with analysis being performed at the zero, first and sixth hour. The particles indeed showed different properties, as all three particles varied in size throughout the experiment. Cobalt had the tendency to decrease in size as time progressed in both solutions, while the mean size of yttrium- and cerium oxide varied. To further our understanding of nanoparticles, more studies need to be performed to properly understand the individual properties of these nanoparticles.

Bei der Schwefelquantifizierung in Kupfer und anderen reinen Metallen zeigte sich in der Vergangenheit eine mangelnde SI-Rückführung und zusätzlich inkonsistente Ergebnisse, wenn verschiedene Methoden verglichen wurden. Um diesen Mangel zu beheben ist ein Referenzverfahren erforderlich, welches SI-rückführbare Werte mit einem zuverlässigen Unsicherheitsbudget ermöglicht. In dieser Studie wurde ein entsprechendes Referenzverfahren zur Quantifizierung von Gesamtschwefel in Kupfer basierend auf der induktiv gekoppelten Plasma-Massenspektrometrie und der Isotopenverdünnungsanalyse (ICP-IDMS) entwickelt. Um diese Probleme zu lösen wurde mit Hilfe der Ionenaustauschchromatographie ein Schwefel-Matrix-Trennverfahren entwickelt. Dieses Trennverfahren wurde mit ICP-IDMS kombiniert, um Schwierigkeiten mit der Kalibrierung zu lösen und fehlende metrologische Konzepte einzuführen. So wurden die in diesem Projekt erzielten IDMS-Messwerte für die Kalibrierung von GDMS und LA-ICP-MS verwendet, beides Verfahren die im industriellen Einsatz üblich sind. Dadurch konnten mit beiden Routineverfahren zuverlässige Ergebnisse erzeilt warden, die zudem auf SI rückführbar sind. Darüber hinaus wurde ein auf der LA-ICP-IDMS basierendes Verfahren entwickelt, um den Probenvorbereitungsschritt von ICP-IDMS mit Schwefel-Matrix-Trennung zu reduzieren. Die Vorteile dieser Methode sind ein geringerer Arbeits- und Zeitaufwand, die SI- Rückführung der Messergebnisse und eine für LA-ICP-MS vergleichsweise hohe Genauigkeit. Die Schlüsselrolle hierbei spielte der innovative Einsatz von Polyethylenfritten als Trägermaterial der aufgelösten Probe. Dadurch war die Quantifizierung von Schwefel in Kupferproben mittels LA-ICP-IDMS möglich. Die wesentlichen Parameter wie Absorptionseffizienz der Fritten und Matrixeffekt wurden untersucht. Das entwickelte Verfahren konnte mit Hilfe der ICP-IDMS vollständig validiert werden. / Sulphur quantification in copper and other pure metals in the past revealed a lack of SI-traceability and also showed inconsistent results, when different methods are compared. Therefore, a reference procedure is required to enable SI-traceable measurement results accompanied by a sound uncertainty budget. In this study, such a procedure was developed for the quantification of total sulphur in copper using inductively coupled plasma-isotope dilution mass spectrometry (ICP-IDMS). For solving these problems ion exchange chromatography was applied, and a sulphur-matrix separation procedure was developed. This procedure was combined with ICP-IDMS to solve difficulties with the calibration and to realize metrological concepts. An application of the IDMS procedure was realized by using the measurement results of specific copper samples values for calibrating glow discharge mass spectrometry (GDMS) and laser ablation ICP-MS (LA-ICP-MS). Both techniques are considered routine techniques. Thus, they could provide reliable results which are traceable to the SI. Additionally, a procedure based on LA-ICP-IDMS was developed to significantly reduce the sample preparation step of ICP-IDMS with sulphur-matrix separation. This procedure is less laborious and the measurement results are still SI traceable and offer a comparatively high accuracy for LA-ICP-MS. Key for this development was the innovative application of polyethylene frits as support material for the dissolved sample. Thus, the quantification of sulphur in copper samples by LA-ICP-IDMS could be realized. The essential parameters are investigated such as the absorption efficiency of the frit and matrix effects. The developed procedure was fully validated by means of the ICP-IDMS results.