[Truncated abstract] The analysis and subsequent interpretation of trace evidence is of paramount importance to the forensic scientist. While a variety of methods are available to facilitate comparison between recovered and control samples, the use of a specific analytical method depends upon both the physical and chemical nature of the material itself and the material to which it is to be compared. Elemental analysis of evidentiary material is one such method of sample comparison and has been extensively applied to this purpose following the introduction of neutron activation analysis in the early 1960s. However, over the last 15 years, another instrumental technique has taken centre stage in the analytical armoury of the forensic scientist: laser ablation–inductively coupled plasma-mass spectrometry (LA-ICP-MS). The modification and adaptation of this technique, to a point where it is possible to distinguish between glass materials produced only hours apart on the same production line, is detailed in this thesis. Additional protocols have also been developed for the analysis of fibreglass and plastic crime scene debris. Finally, a method for quantification of elemental concentrations in headlamp plastics has also been developed to facilitate inter-comparison of data between both different analytical techniques and different laboratories. Glass material is one of the most common varieties of trace evidence and the forensic examination of glass traditionally involves the determination of its refractive index (RI). ... The analytical protocol involves the analysis of 46 analytes on material comprising the exterior surface of the lens. Using this data, it was found that although minor variations in elemental composition exist within a single headlamp lens, discrimination between lenses produced from a single manufacturing plant over a short period of time could still be achieved. Discrimination between all headlamp lenses, with the exception of some lenses produced on the same day, could be facilitated using the analytical protocol developed. Furthermore, an interpretational protocol has been developed that has successfully classified all unknown headlamp lens samples investigated in this study, within the discrimination limits of the analytical method. The semi-quantitative analysis of glass and plastic samples has also been examined using LA-ICP-MS. The concentrations of 16 analytes in container and float glass samples were determined. However, the levels of discrimination afforded by the semi-quantitative data were inferior to those achieved using qualitative data. Finally, a series of plastic-based standards, containing 25 analytes of known concentrations, was produced. Using these standards, relative concentrations of the study analytes were determined in polycarbonate headlamp lenses. Interpretation of the data produced made it possible to discriminate between all study samples. Consequently, the total analytical and interpretational protocol developed in this study has established the foundation for LA-ICP-MS to be adopted internationally as a recognised method for the analysis of plastic crime scene debris.

La LIBS (Laser Induced Breakdown Spectroscopy) est une technique d'analyse élémentaire basée sur l'exploitation du spectre d'émission optique issu de l'ablation laser d'un échantillon. Aujourd'hui, la LIBS ne s'est pas encore imposée comme une technique de choix pour la majorité des applications comme c'est le cas pour les techniques de plasma à couplage inductif. L'une des principales raisons à cela est la difficulté à fournir des mesures quantitatives justes. Il existe donc aujourd'hui une nécessité de mieux comprendre et caractériser les plasmas et les phénomènes issus de l'interaction laser-Matière sur tout type de matériaux pour améliorer les performances de cette technique analytique. Cette interaction laser/matière étant, de plus, spécifique au type de matériau analysé, il est indispensable d'étudier ces effets sur une vaste gamme de matériaux. Deux types d'échantillons ont donc été utilisés pour étudier les plasmas LIBS: des matériaux contenant des terres rares et des matériaux plastiques. Les travaux réalisés sur les terres rares ont permis de sélectionner des raies d'analyse « disponibles », c'est-À-Dire sans interférences spectrales provenant des autres éléments de cette famille et suffisamment sensibles pour réaliser une analyse quantitative. Cette étude a mis en avant le fait que les effets de matrice dus à la quantité de terres rares et à la nature de l'échantillon sont importants. Ces effets de matrice sont propres à chaque élément et à chaque matrice, ils sont donc à prendre en considération pour toute analyse LIBS d'un échantillon contenant plusieurs terres rares. Si l'accumulation d'un grand nombre de terres rares a un effet significatif sur le signal d'un de ces analytes, leurs présences en nombre et quantité limitée (2 à 4) donnent un effet compensable par étalonnage interne. Dans le cadre de l'analyse LIBS des matériaux plastiques, une étude détaillée du signal en utilisant différentes conditions de plasma a été réalisée. L'analyse quantitative s'est portée sur plusieurs éléments dont certains difficiles à exciter comme le brome et le chlore. Grâce à l'utilisation d'une atmosphère contrôlée d'hélium, la détection des halogènes employés comme retardateurs de flamme dans les plastiques, a été possible. Un important effet de matrice a été observé à 266 nm en comparaison avec les résultats obtenus à 532 nm. Cependant, ces différences marquées à 266 nm ont permis la discrimination des quatre familles de polymères étudiées. En présence d'hélium, des différences significatives ont été obtenues pour les rapports C2/He et CN/He. En les traçant l'un en fonction de l'autre, il est ainsi possible de discriminer les différents types de plastiques étudiés / The LIBS (Laser Induced Breakdown Spectroscopy) technique is an elemental analysis technique based on the use of the optical emission spectrum from a sample of laser ablation. Today, LIBS has not emerged as a technique of choice for the majority of applications, as is the case for inductive coupled plasma techniques. One of the main reasons for this is the difficulty in providing accurate quantitative measurements. So there is now a need to better understand and characterize plasmas and phenomena from laser-Matter interaction on all types of materials to improve the performance of this analytical technique. This laser/material interaction is specific to the type of material analyzed, so it is essential to study these effects on a wide range of materials. Two types of samples have been used to study LIBS plasmas: materials containing rare earths and plastics. Work on rare earths were used to select the analytical lines free of spectral interference from other elements of this family and sensitive enough to carry out a quantitative analysis. This study highlighted the fact that the matrix effects due to the amount of rare earth and nature of the sample are important. These matrix effects are unique to each element and matrix, so they are to be considered in all LIBS analysis of a sample containing several rare earths. If the accumulation of a large number of rare earths (i.e 12) has a significant effect on the signal of the analytes, the effect of a limited number (i.e. 2 to 4) could be compensated by use on an internal standard. In the context of the LIBS analysis of plastic materials, a detailed study of the signal using different plasma conditions was performed. The quantitative analysis was focused on several elements, including bromine and chlorine which are difficult to excite. Through the use of a controlled atmosphere of helium, the detection of halogens used as flame retardants in plastics was significantly improved. An important matrix effect was observed at 266 nm in comparison with the results obtained at 532 nm. However, these differences at 266 nm allowed the discrimination of four families of polymers studied. In the presence of helium, significant differences were obtained for the C2 / He and CN / He ratios. This criteria was found to be relevant for the discrimination between the different types of plastics studied

Philosophiae Doctor - PhD / The results of the multivariate analyses suggest that most of the variation in the composition of the samples was of an intra-sample nature, illustrating large scale patchiness in foraminiferal distribution. There were, however, definite differences between communities around Robben Island and in St Helena Bay, and least variation was found between the control and pipeline sites, and between the stations of each site. When the trace metal concentrations and the percentage nitrogen increased, the richness, diversity and abundance of foraminifera tended to decrease. Sediment grain size positively affected abundance but negatively affected diversity and richness. In both areas mean grain size did not, however, appear to play a very large role in influencing diversity. Cadmium, copper, chromium, the percentage nitrogen and the mean grain size were identified as the most important variables influencing the community structure by the BIOENV BEST routine in PRIMER. The trace metals and percentage nitrogen only had negative effects on the diversity and abundance as well as on the abundance of the dominant genera, whereas the mean grain size had variable effects. / South Africa

La spectroscopie sur plasma induit par laser (LIBS) est une technique d'analyse élémentaire couplant l'ablation laser dans le cas des échantillons solides, à la spectroscopie d'émission atomique. Malgré de nombreux avantages qui en font une technique de plus en plus attractive, la spectroscopie LIBS n'est pas encore reconnue comme méthode d'analyse quantitative. En effet, les problèmes d'hétérogénéité des échantillons, d'effets matrice, d'auto-absorption des raies d'émission et surtout de manque de répétabilité participent à la dégradation des performances analytiques de la spectroscopie LIBS. Dans le but de faire évoluer la technique, ces travaux de thèse consistent à réaliser un cas particulier de démonstration de l'évaluation des performances analytiques d'un système LIBS de laboratoire en intégrant des notions de qualité. L'exemple porte ici sur l'analyse d'échantillons d'aciers certifiés. Une première étude concerne le déroulement de l'optimisation du système pour l'analyse quantitative. L'effet des différents paramètres expérimentaux sur le signal LIBS étant complexe, un protocole méthodique est indispensable. Une étude paramétrique est donc ici proposée en vue de déterminer les conditions expérimentales les plus propices à l'analyse quantitative. Une fois optimisée, la méthode LIBS est ensuite caractérisée grâce aux principes classiques de la validation de méthode. La justesse ainsi que la fidélité de la méthode sont évaluées dans des conditions de répétabilité et de précision intermédiaire. Cette dernière étude montre des résultats prometteurs pour la technique. L'application d'une carte de contrôle montre néanmoins un manque de stabilité du système de laboratoire et permet d'enclencher des actions correctives en vue d'améliorer ses performances analytiques. / Laser-Induced Breakdown Spectroscopy (LIBS) is an elemental analytical technique which combines laser ablation with atomic emission spectroscopy. LIBS spectroscopy has many advantages but is not recognized as a fully quantitative method. Indeed, the problem of samples' heterogeneity, matrix effects, self-absorption of emission lines and the lack of repeatability deteriorate the analytical performances of LIBS. In order to improve this technique, the work presented in this thesis includes an example of analytical performances evaluation with the use of quality notions of a laboratory LIBS system. The method is here specially applied to the analysis of certified steel samples. A first study deals with the optimization of the LIBS system for the quantitative analysis. As the effect of the different experimental parameters on LIBS signal is complex, a methodical protocol is necessary. Here, a parametric study is proposed to determine the experimental conditions suitable for quantitative analysis. Once optimized, the LIBS method is then characterized with basics of method validation. The trueness and the precision of the method are evaluated in conditions of repeatability and intermediate precision. This study shows promising results for LIBS technique. The application of a control chart reveals however an instability of the laboratory system and enables to introduce corrective actions to improve its analytical performances.

Le contrôle des procédés représente un enjeu majeur pour les industries chimiques et pétrochimiques afin de garantir la qualité des produits, le contrôle des coûts, le maintien de la productivité et la maîtrise des risques. L'analyse menée directement au coeur des procédés constitue la voie la plus efficace. Cependant, dans la majorité des applications, les analyses élémentaires sont réalisées essentiellement en laboratoire et très rarement en ligne, par la mise en oeuvre de différentes technologies, le plus souvent lourdes et onéreuses. Ce travail de thèse s'inscrit dans le cadre d'un grand projet d'innovation qui couvre le champ de l'analyse élémentaire en ligne, domaine actuellement peu étudié. La technique d'analyse retenue est la spectrométrie LIBS en raison de sa rapidité et de son application à tout état de la matière sans préparation d'échantillon, ce qui lui offre un fort potentiel pour l'analyse en ligne. Cette technique est investiguée afin de réaliser des analyses en ligne d'éléments présents dans des matrices liquides : saumures, huiles silicone et produits pétroliers. L'optimisation des différents paramètres de mesure est réalisée et une approche d'optimisation s'appuyant sur un plan d'expériences est proposée. Différents modes d'échantillonnage de liquide et plusieurs montages LIBS sont étudiés afin de répondre aux problématiques évoquées. Enfin, une transposition au monde industriel est présentée avec le suivi du soufre en ligne dans des produits pétroliers sur un pilote industriel. Les résultats sont encourageants, mais la stabilité perfectible des mesures dans le temps implique d'explorer de nouvelles pistes d'amélioration / Process control is a major challenge for chemical and petrochemical industries so as to ensure product quality, cost control, sustainable productivity and risk management. To do so, carrying out the analysis directly at the core of the process is the most efficient way. However, for most applications, elemental analyzes are mainly performed in the laboratory and rarely on-line, which requires the implementation of different technologies, usually complex and expensive. This work is part of a large innovative project that covers the field of on-line elemental analysis, a research area still understudied to this day. The analytical technique selected here is the Laser Induced Breakdown Spectroscopy. Indeed, its speed and its capability to analyze all states of matter without sample preparation, gives it a great potential for on-line analysis. This technique is investigated in order to achieve on-line analysis of elements contained in various liquid matrices: brines, silicone oils and petroleum products. The optimization of different measurement parameters is performed, including an experimental design based approach. Different liquid sampling configurations and several LIBS setups are designed in order to tackle the issues encountered. Finally, a transposition to the industrial world is presented through on-line monitoring of sulfur in petroleum products on an industrial pilot process. The results are promising, but improving the stability of measurements over time still requires further research

PFAS are anthropogenic substances used in many different industrial operations and products because of their unique properties. Due to their negative impact on human health and environmental bioaccumulative characteristics different authorities have addressed the issue. In Sweden the limit is4 ng/L for four different PFAS in drinking water. Another risk to human health is elevated concentrations of toxic elements, causing Sweden to include them in the drinking water regulations withlimits such as 5 µg/L for arsenic, 25 µg/L for chromium and 5 µg/L for lead.This study is a continuation of an investigation for PFAS remediation in contaminated water by sorption to pine and spruce bark. The earlier study was a laboratory scale and implied that pine and spruce have some sorption capacity for long-chain PFAS. In this study pine and spruce bark were used as sorbent at an industrial site. The analysis was performed by weak-anion exchange extraction followed bysupercritical fluid chromatography coupled with a tandem mass spectrometer (SFC-MS/MS) and liquid chromatography coupled with tandem mass spectrometer (LC-MS/MS) for instrumental analyses of target ultra-short-chain PFAS, short- and long chain PFAS and branched PFOS isomers. An elemental analysis was executed with inductively coupled plasma mass spectrometry. The obtained results indicated removal for certain long-chain PFAS, potential for sorption of a specific ultra-short-chain PFAS and the elemental analysis implied some reduction of the chromium concentrations.

L'utilisation de lasers est largement répandue dans le domaine de la microanalyse directe des solides. La matière vaporisée, en focalisant un faisceau laser de forte puissance sur la cible, peut être analysée soit par spectrométrie d'émission optique sur plasma induit (LIBS, acronyme anglais pour Laser Induced Breakdown Spectroscopy), soit par une source à plasma induit par haute fréquence couplée à la spectrométrie d'émission optique (ICP-AES) ou à la spectrométrie de masse (ICP-MS). Avec une résolution spatiale à l'échelle microscopique, les techniques d'ablation laser permettent ainsi d'accéder à la composition élémentaire locale de la surface d'un matériau. Néanmoins, les performances analytiques de ces techniques pourraient être améliorées par l'utilisation combinée des informations LIBS et ICP afin également de comprendre et maîtriser davantage l'interaction laser/matière. Dans ce but, ce travail a consisté à développer une technique de microanalyse par ablation laser couplée avec une détection en simultané par ICP et par LIBS afin d'étudier les potentialités analytiques de cet instrument pour cartographier la surface des matériaux. Les performances et les limitations de ce système ont été évaluées d'une part, en caractérisant les aérosols produits par ablation laser et d'autre part, en étudiant les signaux LIBS et ICP obtenus à partir d'un même prélèvement de matière. Le phénomène de fractionnement élémentaire rencontré sur des matrices critiques telles que le laiton a été mis en évidence en microablation malgré des caractéristiques de l'interaction laser/matière différente de la macroablation. Une méthode de correction, a posteriori, par l'efficacité d'extraction de la cellule d'ablation a été proposée afin de pallier ces effets limitatifs pour l'analyse quantitative. Une cellule d'ablation, optimisée à partir d'une étude de simulation numérique, a été développée afin de s'adapter aux applications de cartographies de surface. Les performances analytiques du système ont été évaluées en termes de stabilité (8-10%), de résolution spatiale (5 µm) et de limites de détection (de l'ordre de la ppm dans le solide avec un détecteur de masse). La complémentarité des mesures LIBS et ICP représente à la fois un outil de diagnostic de l'interaction laser/matière et un instrument d’analyse très complet grâce à la double détection qui permet de suivre simultanément des traces et des majeurs sur une large gamme d'éléments de la classification périodique / Laser ablation is widely spread for solid sample microanalysis. A tightly focused laser beam allows direct sampling of matter, the ablated mass can then be analysed either with LIBS (Laser Induced Breakdown Spectroscopy) or with an inductively coupled plasma source combined with an optical emission spectrometer (ICP-AES) or a mass spectrometer (ICP-MS). With spatial resolution down to the micron scale, laser ablation techniques permit local elemental analysis of sample surface. Nevertheless, analytical performances of such techniques could be improved by combining LIBS and ICP information to understand and control laser/matter interaction. For this purpose, this work aimed to develop a microanalytical technique based on laser ablation coupled to simultaneous detection with LIBS and ICP to study analytical potentialities of such technique for elemental mapping of material surface. Performances and limitations of the system were studied on one hand, by characterizing laser-induced aerosols and on the other hand, by studying simultaneous LIBS and ICP signals. Elemental fractionation on critical matrices such as brass was evidenced in microablation despite a different laser/matter interaction compared with macroablation. A correction procedure a posteriori using the total extraction efficiency of the ablation cell was proposed to overcome this problem for quantitative analysis. An ablation cell, optimized from a numerical simulation study, was developed for mapping applications. Analytical performances were evaluated in terms of stability (8-10 %), spatial resolution (5 µm) and detection limits (in the ppm range with ICP-MS). The LIBS and ICP complementarity makes the double detection system a diagnostic tool for laser/matter interaction and an analytical instrument allowing simultaneous monitoring of traces and majors from a large element range of the periodic classification

The elemental analysis of soil is useful in forensic and environmental sciences. Methods were developed and optimized for two laser-based multi-element analysis techniques: laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and laser-induced breakdown spectroscopy (LIBS). This work represents the first use of a 266 nm laser for forensic soil analysis by LIBS. Sample preparation methods were developed and optimized for a variety of sample types, including pellets for large bulk soil specimens (470 mg) and sediment-laden filters (47 mg), and tape-mounting for small transfer evidence specimens (10 mg). Analytical performance for sediment filter pellets and tape-mounted soils was similar to that achieved with bulk pellets. An inter-laboratory comparison exercise was designed to evaluate the performance of the LA-ICP-MS and LIBS methods, as well as for micro X-ray fluorescence (μXRF), across multiple laboratories. Limits of detection (LODs) were 0.01-23 ppm for LA-ICP-MS, 0.25-574 ppm for LIBS, 16-4400 ppm for µXRF, and well below the levels normally seen in soils. Good intra-laboratory precision (≤ 6 % relative standard deviation (RSD) for LA-ICP-MS; ≤ 8 % for µXRF; ≤ 17 % for LIBS) and inter-laboratory precision (≤ 19 % for LA-ICP-MS; ≤ 25 % for µXRF) were achieved for most elements, which is encouraging for a first inter-laboratory exercise. While LIBS generally has higher LODs and RSDs than LA-ICP-MS, both were capable of generating good quality multi-element data sufficient for discrimination purposes. Multivariate methods using principal components analysis (PCA) and linear discriminant analysis (LDA) were developed for discriminations of soils from different sources. Specimens from different sites that were indistinguishable by color alone were discriminated by elemental analysis. Correct classification rates of 94.5 % or better were achieved in a simulated forensic discrimination of three similar sites for both LIBS and LA-ICP-MS. Results for tape-mounted specimens were nearly identical to those achieved with pellets. Methods were tested on soils from USA, Canada and Tanzania. Within-site heterogeneity was site-specific. Elemental differences were greatest for specimens separated by large distances, even within the same lithology. Elemental profiles can be used to discriminate soils from different locations and narrow down locations even when mineralogy is similar.

This diploma thesis deals with the influence of dry hopping on selected analytical and sensory properties of beer. The effect of dry hopping was observed using Czech hop varieties Kazbek and Uran, which were added to the wort during the main fermentation phase in doses of 3 and 6 gdm-3. The contact time of hops with wort was 3, 6 and 9 days. The experimental part describes the technology of preparation of the reference beer, in which dry hopping were subsequently performed. A parallel measurement was performed on each sample. In terms of the basic parameters of beer, the effect of dry hopping, especially its length, on the ethanol content was observed. With a longer period of dry hopping, the concentration of ethanol in beer increased. The higher alcohol concentration was also associated with a decrease in the apparent extract. In terms of color and pH of beer, the effect of dry hopping has not been proven. Elemental analysis performed by optical emission spectrometry with inductively coupled plasma revealed an increase in the concentration of calcium, magnesium, and iron due to dry hopping. No statistically significant difference was observed for manganese and barium compared to the reference. In terms of bitterness, a significant increase was identified in dry hopped beers compared to the reference, the value being dependent on the dose of hops used. The effect of the hop variety has not been proved. Concentrations of organic acids determined by ion-exchange chromatography with a conductivity detector were affected by dry hopping only in the case of lactic acid and acetic acid. An increase in lactic acid was observed compared to the reference, also related to the degree of fermentation. While in the acetic acid content the hop samples showed a lower concentration than the reference sample. The concentrations of myrcene, humulene and geraniol were determined by gas chromatography with a mass detector. These are volatile components of hop essential oils. Dry hopped samples recorded significantly higher concentrations of all aromatic substances compared to the reference. In terms of hop time, the highest concentrations were shown by samples hopped for three days. The results of the sensory analysis show that the overall best rated sample is a sample hopped with the Kazbek variety with a dose of 3 gdm-3 for three days. Beer which was dry hopped for the shortest time also showed the lowest intensity of bitterness, which was perceived positively.

This paper builds on previous research of aminoclay complexes in undergraduate studies. Theoretical part deals with study of current problems of aminoclay complexes with bioactive substances and the choice of substances for complexing with aminoclay. The experimental part consists of preparation of aminoclay complexes with selected bioactive agents at various concentrations. Verification of binding of bioactive agents to the aminoclay matrix was performed by Elemental Analysis (EA) and Fourier-transform infrared spectroscopy (FT-IR). For finding of the bound amount of bioactive substance were used the Ultra Performance Liquid Chromatography (UPLC®) and analysis of the cytotoxic properties of the formed complexes by used by the MTT assay. The main motivation of this study is to create new complexes with improved characteristics that would replace existing forms of substances used in pharmaceutical and biomedical applications.