Ga,Ge,As,Se and Sb in coal fly ash S and Pb in gasoline

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Thesis (M.Sc.)--Memorial University of Newfoundland, 2001. / Bibliography: leaves 109-115. Also available online.

Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 19, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Thesis advisor: Dr. John D. Robertson. Includes bibliographical references.

The application of inductively coupled plasma time-of-flight mass spectrometers (ICP-TOFMS) coupled to electrothermal vaporization (ETV) presents several unique analytical opportunities for isotopic analysis. This dissertation explores several subjects that utilize these characteristics in specific analytical applications. The viability of using the thermal programming abilities of the ETV in order to separate Rb and Sr is explored. These elements are isobaric at m/z 87, and must normally be separated prior to analysis for isotopic studies. Their disparate thermal properties allow them to be separated in time by the ETV allowing for simpler, faster isotope ratio analysis with less opportunity for contamination. A test case using standard potassium feldspar is found to produce moderately accurate and precise results. TOF instruments are of interest for isotope ratio analysis due to inherent isotope ratio precision. However, it has been observed that when operated in the analog data collection mode the isotope ratios observed possess a previously uncharacterized inaccuracy. This bias is rooted in variable detection efficiency of arriving ions, which can be corrected for with an algorithm described within. A method of determining the effective detector efficiency as a function of signal is presented, as well as an evaluation of the effectiveness of ratio correction. The use of ETV with TOF for isotope dilution analysis is explored. Correction of transient signals for efficiency effects is discussed, as well as the viability of using the autosampler for mixing of the solution and spike. A final study presents explores the combination of the ETV and TOF for analysis of a large number of elements from a brief transient signal. A library of peptide covered beads is analyzed for binding capacity to a variety of metals. Solutions containing metals stripped from the beads are analyzed to determine the binding capacity and specificity of the peptide sequence. The beads themselves are also analyzed for metal content using the ETV as an indicator of the efficiency of metal stripping off of the beads. / text

Both electrothermal vaporization (ETV) and nebulizer introduction sources offer unique advantages for inductively coupled plasma mass spectrometry (ICP-MS) analyses. A device for coupling the ETV and nebulizer was developed so that a quick switch from the nebulizer to the ETV (termed 'inline-ETV') could help gain additional information. The inline-ETV produced similar limits of detection (LODs) for most elements in both HNO₃ and HCl matrices compared to a conventional nebulizer or ETV. However, in a problematic matrix, isobaric interferences could exist that may not be accounted for in a typical nebulizer analysis. In a 1% HCl matrix, the LODs for ⁵¹V and ⁵³Cr--which are interfered with by ⁵¹ClO⁺ and ⁵³ClO⁺, respectively--improved 65- and 22-fold using the inline-ETV source compared to a typical nebulizer. In recent applications, ICP-MS has gained attention as a way of determining metal-protein associations. A novel broad-based methodology was developed to characterize metal-protein associations. The method utilized native gel electrophoresis for separation followed by electroblotting onto chemically-modified quartz membranes. The membranes were analyzed for metals using laser ablation ICP-MS. Modified membranes were shown to improve sensitivity compared to ablating a dried gel directly or using a commercially-available membrane. The coupling of separation by preparative ultracentrifugation and metal detection by ICP-MS was explored for metal-protein equilibrium determinations. This study characterizes the stoichiometry as well as apparent (K[subscript app]) and intrinsic (K[subscript int]) binding affinities for Cu-BSA, which was used as a model protein. K[subscript app] and K[subscript int] were determined at two different conditions, pH 9.53 and pH 7.93 in 100mM Tris buffer. The pH-independent K[subscript int] value at pH 9.53 agreed closely with literature values, while the value at pH 7.93 was approximately 2.5x larger. BSA undergoes a structural rearrangement between pH 7-9, and the generally accepted pH-dependency of protein tertiary structure may be responsible for the variations in the "intrinsic" binding constant. Overall, this study validates and shows the efficacy of combining preparative ultracentrifugation with ICP-MS detection for interrogating metal-protein associations while causing minimal equilibrium perturbations as a result of the separation and measurement processes. / text

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

The radiological dispersal device (RDD) is a weapon of great concern to those agencies responsible for protecting the public from the modern age of terrorism. In order to effectively respond to an RDD event, these agencies need to possess the capability to rapidly identify the radiological agents involved in the incident and assess the uptake of each individual victim. Since medical treatment for internal radiation poisoning is radionuclide-specific, it is critical to identify and quantify the radiological uptake of each individual victim. This dissertation describes the development of automated analytical components that could be used to determine and quantify multiple radionuclides in human urine bioassays. This is accomplished through the use of extraction chromatography that is plumbed in-line with one of a variety of detection instruments. Flow scintillation analysis is used for ⁹⁰Sr and ²¹⁰Po determination, flow gamma analysis is used assess ⁶⁰Co and ¹³⁷Cs, and inductively coupled plasma mass spectrometry is used to determine actinides. Detection limits for these analytes were determined for the appropriate technique and related to their implications for health physics.

published_or_final_version / abstract / toc / Chemistry / Master / Master of Philosophy

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