Most methods for the determination of trace elements in organic matter require the sample to be brought into solution, which may be achieved by heating with strong oxidising agents such as concentrated mineral acids, to decompose the organic matrix sufficiently to render the sample soluble, whilst not necessarily achieving complete decomposition. The use of microwave heating for this purpose, using sealed vessels under pressure, was investigated for a variety of food samples. One drawback of this otherwise rapid method is the time taken to cool the vessels before opening. The use of liquid nitrogen to cool the vessel walls - before, during and after the heating cycle - was investigated, and its effect on the progress of the digestion was assessed. Another problem is the control of internal pressure, which can rise very rapidly when digesting samples of high organic content, and ways of controlling excess pressure when digesting larger samples were devised. These included the use of an open pre-digestion under reflux using a microwavetransparent coolant liquid, and the use of vessels capable of withstanding higher pressures. The latter proved more convenient as they enabled complete dissolution to be achieved in a single stage without pre-digestion, although cooling of these vessels was much slower than for the low pressure vessels, so overall sample preparation time was similar. Various methods were developed for the complete dissolution of the samples using nitric acid and hydrogen peroxide. The degree of decomposition achieved for the different methods and sample types was monitored by measurement of residual carbon in the digests. A few samples were virtually completely decomposed with nitric acid alone, while the use of hydrogen peroxide, following a nitric acid digestion, was found to reduce residual carbon substantially in the others. The undecomposed material was analysed by various methods including ultraviolet/visible spectrometry, infrared spectrometry and thin layer chromatography. Decomposition products were found to include carboxylic acids, oxalates, phosphates, nitrates and nitro-aromatics. Complete decomposition of milk powder, which proved most resistant to oxidation, was achieved by further treatment with perchloric acid. This was found necessary for anodic stripping voltammetric analysis, which required the destruction of interfering organic species for accurate determination of trace elements, unlike other techniques such as inductively coupled plasma-mass spectrometry, where complete decomposition was not required.

A summary of the fundamental principles which form the basis of proton induced X-ray emission (PIXE) analysis, proton induced gamma-ray emission (PIGE) analysis, Rutherford backscattering spectrometry (RBS) and instrumental neutron activation analysis (INAA) has been given which is followed by a brief description of the experimental facilities used in this work and their characterization. Knowledge of optimum experimental conditions is always helpful, therefore a programme has been developed to simulate the PIXE spectra and its uses have been described. Reference materials with certified elemental concentrations play an important role in ensuring the accuracy of the elemental analysis work. The FIXE technique has been applied to the analysis of new biological reference materials which consist of IAEA human diet samples and NIST leaf samples, to be introduced in the future. Homogeneity of these and two existing reference materials that is, IAEA soil-7 and Bowen's kale has also been determined at the mug scale. A subsample representative of a material is ascertained by determination of sampling factors for the elements detected in the material. Use of PIXE has been established in experimentally obtaining sampling factors for the above mentioned materials. PIGE analysis in conjunction with PIXE has been employed to investigate F and other elemental concentrations found in human teeth samples. The mean F concentration in enamel and dentine parts of teeth followed an age dependent model. The lowest F concentrations were observed in two out of three careous teeth. Concentrations of Ca and P were found to be higher in the enamel than in the dentine in all the teeth analyzed. Analysis of blood and its components in the study of elemental models in sickle cell disease in Nigerians has been carried out. A total of eight elements were detected. Comparision was made between controls and diseased groups which revealed that Cl, Ca and Cu were at significantly higher levels whereas K, Fe, Zn and Rb were at significantly lower levels in the whole blood of the sicklers as compared to the controls. Similar results were obtained for the erythrocytes except that Br was also found at significantly higher concentration in erythrocytes of the sicklers. Significantly higher concentrations of Cl, K, Fe and Cu were also observed in plasma of the sicklers as compared to that of the controls. Elemental status of the normal controls was found to be comparable to that of the Uzbekistanians (USSR) and North Americans but was better than that of the Bangladeshi population. PIXE and scanning electron microscopy (SEM) was used in the characterization of the Harmattan dust particulates collected at Kano and Ife, two cities of Nigeria. Most of the elements were found to be at higher concentrations as compared to those found in Recife (Brazil) and Toronto (Canada). The value of total suspended particulate matter (TSPM) at both collection sites was also above the relevant national (USA) air quality standards. FIXE in conjunction with RBS and INAA was employed in the analysis of soil samples taken at various depths from within and around two cement factories in Nigeria thereby detecting 31 elements. The results have been discussed with reference to elemental concentrations and Ca/Si ratio. The latter was found to offer a valid indicator of soil pollution by the cement dust.

Various lines of evidence indicate that levels of anthropogenic pollutants, such as lead, mercury and cadmium, have increased in terrestrial and atmospheric environments since the early 19th century and the advent of industrialization. While the exposure to these three trace elements is a global concern, this study focused primarily on marine environments located throughout the Caribbean. Using ICP-MS, this study aimed to detect and quantify anthropogenic pollutants, specifically lead (Pb), mercury (Hg) and cadmium (Cd), using skeletonized remains of sea turtles as biological proxies for environmental quality. Archaeologically derived (n=5) and mid-late 20th century (n=6) Hawksbill and Green turtles were used to create a chronology of pollution exposure in Caribbean marine environments and establish a pre-industrial baseline for pollution exposure, useful for precisely gauging how human activities in the Caribbean, namely industrialization and tourism, have changed the concentration of these elements over time. Results from this study revealed that the industrial, modern sea turtle sample and the archaeological sample exhibit similar distributions of lead and cadmium ppm levels. Whereas, the mercury datasets revealed that the two samples share differing distributions of ppm levels, but that the archaeological sample yielded the higher mercury concentrations. Based on these results, this study was unable to verify whether skeletal sea turtle remains, specifically humeri, can be used as a biological proxy to reconstruct anthropogenic pollution in marine environments. Furthermore, it failed to quantify pre-industrial to mid-late 20th century anthropogenic lead, mercury, and cadmium pollution in Caribbean Marine Environments.

The goal of this research was to devise a new analytical technique, using Accelerator Mass Spectrometry (AMS), to measure Platinum Group Element (PGE) concentrations to the sup-ppb levels in natural, insulating, samples. The challenges were threefold. First, a method of sputtering an insulating sample to successfully produce a stable beam of anions needed to be devised. Second, a suitable standard of known PGE concentrations had to be found and third, spectral analysis of the beam had to verify any claims of PGE abundance. The first challenge was met by employing a modified high intensity negative ion source flooded with neutral caesium that successfully sputtered insulators to produce a beam of negative ions. The second challenge, that of finding a suitable standard, was fraught with difficulties, as no synthesized standards available were found to be appropriate for this work. As a result, direction is provided for future production of standards by ion implantation. The third challenge, successful spectral analysis, was accomplished using a newly designed gas ionization detector which allowed for resolution of the interfering molecular fragment from the PGE ions. Coupled with the use of the SRIM computer programme, positive identification of all peaks in the spectra of the analyzed samples was accomplished. The success of the first and third challenges lead to the qualitative analyses of geological samples for sub-ppb levels of PGE by AMS. Quantitative analyses await only for the appropriate standards and with those will come a whole new range of research possibilities for measuring sub-ppb levels of PGE in insulating samples by AMS.

This thesis is concerned with the manufacture of copper artefacts by the users of Bell Beaker pottery in the Eastern Bell Beaker group in central Europe, and addresses the question: did these metalworkers have distinct metallurgical abilities, techniques and preferences that set them apart from contemporary and earlier metal-using groups in the same region? Can we talk of a 'Bell Beaker' metallurgical tradition? Despite the long history of research into the so-called Bell Beaker phenomenon, there has been no definite answer to this question. The composition of copper artefacts is influenced by the production process and the composition of the ore, and so two artefacts that share a similar composition reflect a metallurgical similarity. Artefact composition is defined by variations in trace element impurities that are contained in the copper. Trace elements, however, do not only point to metallurgical processes: they also affect the physical and chemical properties of the metal. Consequently, this thesis aims to clarify whether the distribution of the Bell Beaker phenomenon throughout central Europe and its dissociation from other archaeologically visible groups there is associated with the use of a specific metallurgical tradition. It will be argued that if metal workers of other archaeological groups of the 3rd millennium BC, such as the Corded Ware complex, dealt with different types of copper, having different properties, this would give an insight into the relationship between those people and the Bell Beaker phenomenon in central Europe. In order to explore these issues, a database of some 1943 trace element analyses of Chalcolithic copper objects from central Europe has been created, then statistically grouped and evaluated according to two questions: firstly, were metalworkers selecting specific types of copper for their physical and chemical properties? Secondly, are Eastern Bell Beaker copper artefacts made from specific types of copper? The result of the statistical evaluation has demonstrated that, generally, copper artefacts with higher impurity levels are more common throughout the 3rd millennium BC than in earlier periods. In particular, higher concentrations of arsenic, antimony, lead and nickel (> c. 2%) indicate that these types of copper have improved properties (e.g. hardness, tensile strength, malleability). Furthermore, with the appearance of archaeological remains classified as belonging to the Earliest Bronze Age (e.g. the Blechkreis and the Nitra group), there is an almost exclusive use of types of copper that contain even greater quantities of antimony, nickel and arsenic. These types of copper may have been preferred by metalworkers because their superior tensile strength and hardness improves the quality an artefact. It therefore appears that the metallurgical properties of copper were gradually improved throughout the Chalcolithic in central Europe. It seems that there was a network distributing copper over the area of this research, because the types of copper used by the Eastern Bell Beaker group do not show great regional variation. The uniformity of the archaeological records of the Eastern Bell Beaker group is also reflected in their metalworking tradition. However, it was for the first possible to clarify that the people of the Eastern Bell Beaker group did not deal with a specific type of copper compared with other archaeological groups. Bell Beaker copper types do not differ from those generally used throughout the 3rd millennium BC, albeit that only a small set of Bell Beaker artefacts (chiefly daggers and awls) has provided trace element analyses. As neither regional nor cultural specific metallurgy can be detected for this period, it is argued that the Eastern Bell Beaker group is – at least in metallurgical terms – connected with other local communities in central Europe. Consequently, metallurgy cannot be cited as a defining factor of archaeological groups in central Europe during the 3rd millennium BC. In terms of the Corded Ware and Bell Beaker groups, metallurgical expertise was probably at the same level of knowledge. Hence, even if the types of copper artefact that were manufactured were ‘culture-specific’, the manufacturing techniques and the access to resources were not restricted to a single archaeological group. It can therefore cautiously be suggested that, between c. 2700 and 2000 BC, metallurgists – perhaps as itinerant craftsmen – produced copper artefacts according to the demands of their ‘customers’.

Elemental analysis of pottery sherds provided insights on the ceramic production in the Huancabamba Valley (northern highland-Peru) and the way in which the Incas administrate the provinces. The pottery sherds from six archaeological sites selected for elemental analysis indicated the use of similar clay sources in the manufacture of pottery. The production of ceramic vessels took place at the local level without the strict control of the Inca state. The Incas built administrative structures in the Huancabamba Valley in order to maintain control of their road system, which connected the north area of Peru to Ecuador. The ceramic assemblage recovered from Inca sites does not illustrate typical Inca pottery style or decoration from the heartland. The administrative centers built by the Incas throughout the Empire provided the means to support state activities such as pottery production of local wares. In addition, ethno-historic evidence suggests that during the Inca period coastal communities were relocated to highland settlements in order to serve as officers in state facilities, or to maintain the Inca road system. These coastal communities continue producing pottery following the traditional techniques from their homeland.

The goal of this research was to devise a new analytical technique, using Accelerator Mass Spectrometry (AMS), to measure Platinum Group Element (PGE) concentrations to the sup-ppb levels in natural, insulating, samples. The challenges were threefold. First, a method of sputtering an insulating sample to successfully produce a stable beam of anions needed to be devised. Second, a suitable standard of known PGE concentrations had to be found and third, spectral analysis of the beam had to verify any claims of PGE abundance. The first challenge was met by employing a modified high intensity negative ion source flooded with neutral caesium that successfully sputtered insulators to produce a beam of negative ions. The second challenge, that of finding a suitable standard, was fraught with difficulties, as no synthesized standards available were found to be appropriate for this work. As a result, direction is provided for future production of standards by ion implantation. The third challenge, successful spectral analysis, was accomplished using a newly designed gas ionization detector which allowed for resolution of the interfering molecular fragment from the PGE ions. Coupled with the use of the SRIM computer programme, positive identification of all peaks in the spectra of the analyzed samples was accomplished. The success of the first and third challenges lead to the qualitative analyses of geological samples for sub-ppb levels of PGE by AMS. Quantitative analyses await only for the appropriate standards and with those will come a whole new range of research possibilities for measuring sub-ppb levels of PGE in insulating samples by AMS.

In anthropology, elemental analysis of bone and teeth can provide significant details about an individual’s life history, such as diet, toxicity exposure, residency, and migration patterns. Intra-individual comparisons can help to gather information about a single individual’s life, while inter-individual comparisons can help illustrate a community’s life history during these periods. However, current methods of elemental analysis commonly involve the destruction of skeletal samples, which can damage a collection’s integrity and be perceived as disrespectful by descendant communities. Preliminary research has validated handheld x-ray fluorescence spectrometry (HHXRF) as an accurate and reliable method of analysis appropriate for determining the elemental composition of archaeological bone and teeth. In this study, teeth from 16 individuals (N=16) from the pre-conquest Classic Period (AD 625-1100) Maya site of Altun Ha, Belize, were analyzed using HHXRF to identify trace elements to gain a better understanding of the lives of the individuals and community. This study expands upon preliminary research by increasing the sample size and utilizes a filter to increase sensitivity to elements of interest. Diet and mobility were assessed using calcium (Ca), strontium (Sr), and bromine (Br) ratios. Net photon counts per element of interest were extracted and converted into ratios. An inter- and intra-individual comparison model was used. Results of calculated Sr/Ca ratios show a general increased reliance on marine subsistence sources within the sample. Shifts that do not align with this trend are present in several individuals, indicating social complexity of Altun Ha. Results of Br/Ca ratios are less clear in regard to diet and warrant further investigation.

This master's thesis covers an investigation of the reduction behavior of different iron oxides when electrolytically reduced with molten salt electrolysis (MSE). The tested iron oxides were wüstite (FeO), hematite (Fe2O3), magnetite (Fe3O4) and magnetite ore concentrate from the Tapuli deposit in Pajala, Norrbotten, Sweden. The properties of the Tapuli magnetite ore and magnetite ore concentrate were analysed from a mineralogical perspective to evaluate how the raw ore material influences the concentrate and its reduction by the MSE technology. The electrolytic experiments were performed in an Inconel 625 cell body within a pit-furnace. The different iron oxides were tested separately. The reduction samples were constructed of one or three iron oxide briquettes of 20 g each within a molybdenum mesh attached on a molybdenum tray with molybdenum wires. The molten electrolyte was kept at 500°C with an applied voltage of 1.7 or 2.1 V. The used electrolyte was sodium hydroxide (NaOH). The mineralogical examination shows that the Tapuli ore varies in composition between different locations of the deposit with respect to magnetite grain size and skarn composition and grain size. Point analyses with Laser Ablation Single Collector Inductively Coupled Plasma Mass Spectrometry (LA-SC-ICP-MS) on magnetite grains in thin sections from five drill cores fromdifferent parts of the deposit show that the element composition in the magnetite grains vary between the samples. Core-to-rim analyses for Fe, Mg, Mn and Al reveal relatively homogenous grades throughout the grains, with a few exceptions. Phase analysis with XRD shows that reduction has occurred in all tested iron oxides. Without prevention, the reduction products from trials on Fe2O3, Fe3O4 and magnetite ore concentrate show distinct XRD peaks of the by-product NaFeO2. According to XRD, the addition of Na2O seems to have reduced the NaFeO2 formation. Interestingly, no NaFeO2 was formed in the FeO trials. This might be explained by the absence of Fe3+ in FeO. The variation of the current-time curves of the trials is interpreted to depend on the voltage applied, the number of briquettes, briquette decomposition and Na2O addition. Electrolysis in molten NaOH can be used to reduce iron oxides. Despite this, NaOH might not be a suitable electrolyte for this process due to its interaction with Fe2O3 and Fe3O4 resulting information of NaFeO2. Na2O can be used as an additive to prevent formation of NaFeO2 but sharply decreases the current response, thus having an apparent negative effect on the process efficiency. Another preventive measure that can be tested is to calibrate the process voltage to decompose the NaFeO2 but not NaOH. Due to the shown interaction tendency of NaOH, other electrolytes should however be considered for this process. Regarding the Tapuli ore concentrate, more tests are needed to draw conclusions about how the trace elements effects its electrolytic behavior. / Denna masteruppsats avhandlar en undersökning av reduktionsbeteendet hos olika järnoxider vid elektrolytisk reduktion i saltsmälta (molten salt electrolysis (MSE)). Järnoxiderna som har testats är wüstit (FeO), hematit (Fe2O3), magnetit (Fe3O4) och magnetitmalmkoncentrat från malmfyndigheten Tapuli i Pajala, Norrbotten, Sverige. Malmkoncentratets egenskaper har analyserats ur mineralogisk synvinkel för att utvärdera hur den råa malmens mineralogi påverkar koncentratet och dess reduktionsbeteende vid elektrolys i saltsmälta. Elektrolysexperimenten utfördes i cellkropp av Inconel 625 placerad i en gropugn. De olika järnoxiderna testades separat. Reduktionsproverna utgjordes av en eller tre järnoxidbriketter på 20 g inuti ett molybdennät, fastvirade på en molybdenbricka med molybdentråd. Den smälta elektrolyten hölls vid en temperatur av 500°C med en applicerad spänning av 1.7 eller 2.1 V. Elektrolyten som användes var natriumhydroxid (NaOH). Den mineralogiska undersökningen visar att tapulimalmens sammansättning varierar mellan olika delar av fyndigheten med avseende på magnetitens kornstorlek och skarnets sammansättning och kornstorlek. Punktanalyser med Laser Ablation Single Collector Inductively Coupled Plasma Mass Spectrometry (LA-SC-ICP-MS) på magnetitkorn i tunnslip från fem olika borrkärnor visar att elementkoncentrationerna i magnetitkornen varierar mellan proverna. Core-to-rim-analyser på magnetitkornen visar att halterna av Fe, Mg, Mn och Al är tämligen homogena genom hela magnetitkornet med undantag av några få avvikande punkter. Fasanalys med XRD indikerar att reduktion har skett i alla försök. Utan prevention visar reduktionsprodukterna från försöken på Fe2O3, Fe3O4 och magnetitmalmkoncentrat klara indikationer av biprodukten NaFeO2. Enligt XRD verkar tillsats av Na2O ha minskat bildningen av Na2O för Fe2O3, Fe3O4 och Tapuli magnetitmalmkoncentrat. Intressant är att ingen NaFeO2 bildades i försöken med FeO. Förklaringen till detta skulle kunna vara avsaknaden av Fe3+ i FeO. De varierande ström-tidkurvorna från försöken tolkas bero på den applicerade spänningen, antalet briketter, brikettsönderdelning och tillsats av Na2O. Elektrolys i smält NaOH kan användas för att reducera järnoxider. Trots detta kanske NaOH inte är lämplig som elektrolyt i denna process, detta på grund av dess påvisade interaktion med Fe2O3 och Fe3O4 som resulterar i bildning av NaFeO2. Na2O kan tillsättas för att förhindra bildning av NaFeO2 men har en kraftigt negativ effekt på strömstyrkan i processen vilket minskar processens effektivitet. En annan preventiv åtgärd som kan testas är att kalibrera processens spänning så att NaFeO2 sönderdelas men inte NaOH. På grund av den konstaterade interaktionstendensen hos NaOH bör andra elektrolyter tas i beaktande för denna process. Angående magnetitmalmskoncentratet från Tapuli behövs fler tester för att dra slutsatser kring hur spårelementen påverkar dess uppförande vid smältelektrolys.

Um estudo sistemático a respeito da utilização de padrão interno em determinações multielementares por espectrometria de absorção atômica (ETAAS) foi desenvolvido. O objetivo principal do presente trabalho foi verificar a possibilidade de melhorar a precisão e a exatidão dos resultados analíticos, que são obtidos na análise de fluidos biológicos. O pré-tratamento dessas amostras foi simplificado e reduzido a uma única etapa de diluição com surfactante (Triton X-100) e ácido (HNO3). Conseqüentemente, a complexidade da solução diluída de amostra, a ser introduzida no tubo de grafite, apresenta uma elevada quantidade de concomitantes que podem provocar interferências químicas. A seleção preliminar dos elementos a serem testados como padrão interno considerou a semelhança de parâmetros físico-químicos relacionados com o processo de atomização. Desta forma, Ag, Bi, In e Tl foram testados como padrão interno para a determinação simultânea de Cd/Pb em sangue e urina, enquanto Bi, Ge, In, Sb, Sn e Te foram os elementos selecionados para a determinação de Mn/Ni/Se em soro sangüíneo. A melhoria da qualidade dos resultados analíticos obtidos na determinação simultânea de Cd e Pb em sangue foi observada quando Ag foi utilizada como padrão interno, na presença de NH4H2PO4 como modificador químico. Verificou-se uma melhoria na exatidão dos resultados obtidos para Cd e Pb, após a correção com padrão interno. Por outro lado, os resultados obtidos na análise de urina não foram corrigidos por nenhum dos elementos testados. Os melhores resultados para a determinação simultânea de Mn, Ni e Se foram obtidos com a utilização de Bi, Sn e Te como padrão interno. Entretanto, verificou-se que a correção de todos os resultados não seria viável com o uso de um único padrão interno. O melhor desempenho nos testes realizados na presença de soro sangüíneo foi obtido com Bi, que melhorou discretamente a precisão dos resultados obtidos para Se. Desta forma, a padronização interna visando a determinação simultânea de Mn, Ni e Se não foi eficiente. A padronização interna em ETAAS, com a finalidade de melhorar a precisão e a exatidão dos resultados analíticos, é uma estratégia tão complexa, quanto os efeitos interferentes que se pretende corrigir: são necessários mais estudos para compreender melhor como a utilização de uma condição de compromisso afeta os processos de atomização, bem como mais informações a respeito das interferências físicas e químicas causadas por amostras complexas, analisadas por ETAAS após uma simples etapa de diluição. Deve-se considerar com especial atenção o modificador químico e as temperaturas das etapas de pirólise e de atomização empregadas, que são parâmetros críticos para o desempenho de um elemento como padrão interno. / A systematic study involving the use of internal standard for multielement determinations by electrothermal atomic absorption spectrometry was developed. The main objective of this work was evaluate the possibility of improving precision and accuracy of the analytical results for biological fluids. The sample pre-treatment was reduced to a single dilution step with surfactant (Triton X-100) and acid (HNO3), increasing the amount of concomitant introduced into the atomizer. The preliminary selection of the elements to be tested as internal standard considered the resemblance of physico-chemical parameters related with the atomization process. Thus, Ag, Bi, In and Tl were tested as internal standard for the simultaneous determination of Cd/Pb in blood and urine, and Bi, Ge, In, Sb, Sn and Te were the selected elements for the determination of Mn/Ni/Se in blood serum. The correction of the results obtained for the simultaneous determination of Cd and Pb in blood was achieved when Ag was used as internal standard, in presence of NH4H2PO4 as chemical modifier. An improvement for the accuracy of the results was observed for both analytes after their correction with the internal standard. On the other hand, the results obtained for the urine analysis were not corrected by using the tested elements. The best results for the simultaneous determination of Mn, Ni and Se were observed when Bi, Sn and Te were used as internal standard. However, the correction for the results for all analytes was not possible by using only one internal standard. The best performance in presence of the serum was obtained for Bi, which improves slightly the precision for the Se results. Thus, the internal standardization for the simultaneous determination of Mn, Ni and Se was not efficient. The internal standardization in ETAAS, aiming the improvement of precision and accuracy of the analytical results, is a strategy as complex as the interference effects to be corrected: more studies are required in order to better understand how the adoption of a compromised condition disturbs the atomization processes, as well as to get more information about the physical and chemical interference caused by complex samples, analyzed by ETAAS after a single dilution step. The chemical modifier and the selected temperatures for the pyrolysis and atomization steps are critical parameters for the performace of an internal standard and they should be carefully considered.