Dans l’industrie, les sources d’expositions aux particules ultrafines (PUF) sont nombreuses et connues depuis longtemps. Ces particules quelles soient manufacturées ou non intentionnelles (générées au cours de procédés industriels) présentent des propriétés singulières qui impliquent des effets sur la santé différents de ceux induits par des particules de plus grande taille (micrométrique). L’étude spécifique des PUF nécessite donc le développement de méthodes de prélèvement et d’analyse adaptées permettant d’obtenir des informations pertinentes complémentaires à la masse totale de poussières prélevées. Cette métrique semblerait insuffisante pour caractériser correctement les effets toxiques des PUF. La thèse a donc été menée dans l’optique de disposer de méthodes dédiées à l’analyse des nanoparticules et en particulier sur la caractérisation chimique des particules en fonction de leur taille (couplage entre dispositifs de prélèvement en fonction de la taille des particules et méthode d’analyse). Les méthodes développées ont ensuite été testées sur des échantillons provenant soit de sites et/ou procédés industriels (fonderie, projection thermique) soit d’essais en laboratoire par prélèvement sur banc de génération de PUF. / Expositions to nanoparticles (NPs) are known in industrial hygiene for a long time. Either from primary or secondary sources (industrial processes), these particles have specific properties which imply different toxicities compared to larger particles (micrometric) from the same material. Therefore NPs study requires adapted sampling and analytical technique development and more specifically methods allowing to access relevant information other than total dust mass. The latter seems not be sufficient for toxic effect assessment. Thus, this work has been conducted in order to dispose of analytical methods dedicated to NPs and especially on size-dependent particle chemical analysis. Then, the developed methods have been applied on samples collected either from industrial sites and/or processes (smelter, thermal projection), either from NP generation bench.

Les ions métalliques (Fe, Zn, Cu, Mn, Ni, Co, Mo…) jouent un rôle vital dans un grand nombre de processus biologiques. Leur carence et leur excès entraînent des défauts de croissance voire la mort. Pour survivre et croître, certaines bactéries ont développé des stratégies pour acquérir les métaux dans leur environnement basées sur la synthèse de ligands complexant les métaux. Les plantes, elles, stockent les métaux et les transportent entre les tissus sous des formes chimiques particulières et un rôle grandissant pour les petits complexes métalliques semble se révéler. La spéciation des métaux gouvernerait donc leur biodisponibilité pour les consommateurs en ce qui concerne les plantes comestibles. Cette thèse a pour but le développement de méthodes analytiques pour l’identification et la quantification des formes chimiques des métaux chez les bactéries et les plantes.Les techniques de séparation chromatographique, comme la chromatographie d’exclusion stérique (SEC) et la chromatographie d’interaction hydrophile (HILIC), furent couplées à la spectrométrie de masse (MS) avec une ionisation préalable par plasma induit (ICP MS) ou par électrospray pour une détection élémentaire et moléculaire respectivement. La méthodologie analytique développée ici, qui est basée sur l’utilisation de l’HILIC avec détection double par ICP MS et électrospray MS, s’est avérée cruciale pour la découverte et la caractérisation de deux nouveaux métallophores, la staphylopine chez Staphylococcus aureus et la pseudopaline chez Pseudomonas aeruginosa. Ces métallophores sont synthétisés et exportés par les bactéries et servent pour l’acquisition des métaux de transition divalents dans les milieux très pauvres en métaux grâce à leur pouvoir complexant.Des techniques dédiées de préparation d’échantillons, incluant le fractionnement des extraits solubles à l’eau, furent mises en place pour l’analyse du fer dans le maïs. Les approches instrumentales développées, notamment après le fractionnement du fer l’échantillon, permirent l’identification par spectrométrie de masse de complexes du fer avec le citrate, le muginéate et le phytate dans les grains de maïs. Il existe aussi une différence significative dans les concentrations de certaines polyamines entre certaines variétés de graines contenant du fer faiblement biodisponible et celles contenant du fer fortement biodisponible. La plus grande abondance de complexe fer-muginéate dans les extraits gastro-intestinaux des variétés à fer fortement biodisponible semblerait indiqué un rôle important pour ce complexe dans la biodisponibilité du fer. Finalement, des ratios molaires plus faibles entre le phytate extrait et le fer qui lui est associé sembleraient aussi être un des facteurs lié à une plus grande biodisponibilité du fer. / Metal (Fe, Zn, Cu, Mn, Ni, Co, Mo…) ions play a vital role in a large number of biological processes. Both their deficiency and excess will lead to severe growth impairment or death. In order to survive and to grow, bacteria developed strategies to acquire metals from the environment based on the synthesis of metal complexing ligands. Plants store metals and transport them between tissues in particular chemical forms and a rising role for small metal complexes seems to be revealed. Therefore their speciation governs the bioavailability of the metals to consumers in the case of edible plants. This thesis aims at the development of analytical methods for the identification and quantification of metal chemical forms in bacteria and in plants.Chromatographic separation techniques, such as size exclusion chromatography (SEC) and hydrophilic interaction chromatography (HILIC) were coupled to mass spectrometry (MS) using ionization in an inductively coupled plasma (ICP MS) or electrospray for elemental and molecular detection, respectively. The developed analytical methodology based on HILIC with dual ICP MS and electrospray MS detection turned out to be crucial for the discovery and characterization of two novels metallophores, staphylopine in Staphylococcus aureus and pseudopaline in Pseudomonas aeruginosa. These metallophores are synthesized and exported by the bacteria and serve for the uptake of divalent transition metal in metal scarce conditions by means of chelation. Dedicated samples preparation techniques, including fractionation of water soluble extracts, were developed for iron analyses in maize. The developed instrumental approaches following the iron fractionation methods allowed the identification by mass spectrometry of citrate, mugineate and phytate complexes with iron in maize kernels. There was also a significant difference in some polyamine concentrations observed between some kernels with low and high bioavailable iron. The higher abundance of the iron-mugineate complex in the gastrointestinal extract in high bioavailable maize variety possibly indicates that iron-mugineate would have an important role in iron biodisponibility. Finally, lower molar ratios between extracted phytate and iron associated to it would seem to be also a key aspect for higher iron bioavailability.

No início dos anos 90, os primeiros indícios do tráfico ilícito de materiais nucleares e radioativos foram observados principalmente na região européia. Uma década marcada por inúmeros casos de apreensão desse tipo de material. Como resultado, esses atos passaram a ser alvo de investigações criminais forenses, desenvolvendo-se a partir daí, a ciência forense nuclear. No Brasil não há registros oficiais do tráfico ilícito de material nuclear, entretanto, é amplamente conhecida a extração e o transporte ilegal de materiais geológicos radioativos, assim como a apreensão de fragmentos de materiais utilizados como blindagem de fontes radioativas. Uma das principais ferramentas utilizadas na ciência forense nuclear consiste no estabelecimento de bancos de dados de materiais nucleares. Esses documentos devem conter o maior número possível de informações sobre as características físicas, químicas e nucleares do material apreendido, permitindo a identificação de sua origem, processo de fabricação ou mesmo a idade (age). Assim, se estabelecem padrões de composição característicos de cada material, denominados assinaturas químicas (chemical finger print). Nesse trabalho foi adotado o protocolo forense nuclear seguindo as três etapas de avaliação sugeridas pela Agência Internacional de Energia Atômica (AIEA) na identificação da origem de Siliceto de urânio (U3Si2). Realizaram-se ensaios de caracterização física, química e isotópica dos materiais em estudo e compararam-se os dados com aqueles obtidos para outros compostos de urânio (Tetrafluoreto de urânio, UF4; óxidos de urânio, UO2 e U3O8; tricarbonato de amônio e uranila, TCAU) estabelecendo-se uma assinatura característica para cada um. A partir dos resultados foi possível classificar os compostos por grupos de origem, uma vez que são provenientes de diferentes processos de fabricação e/ ou origem. Demonstrou-se também a importância da criação e manutenção de um banco de dados nuclear na investigação de um evento forense nuclear. / In the early 1990´s, the first illicit trafficking of nuclear and radioactive materials was observed mainly in Europe. A decade marked by numerous cases of seizures of these materials. As a result, these events have become the subject of criminal forensic investigations and develop from there, nuclear forensics. In Brazil there are no illicit trafficking official records of nuclear material, however, is widely known the extraction and illegal transportation of radioactive geological materials, and the materials pieces attachment used as shielding for radioactive sources. One of the main tools used in nuclear forensics is the nuclear materials databases establishment. These documents must contain the most information as possible about the physical, chemical and nuclear material seized, allowing the identification of their origin, manufacturing process or age. Thus, it sets characteristic composition standards of each material, called \"chemical signatures (chemical finger print). In this work nuclear forensic protocol was adopted as well as the three stages of assessment suggested by International Atomic Energy Agency (IAEA) in identifying the origin of uranium silicide (U3Si2). Assays were performed in order to make physical, chemical and isotopic characterization of the studied materials and compared the data with those obtained for other uranium compounds (Uranium tetrafluoride, UF4; uranium oxide, UO2 and U3O8; Yellow cake) by establishing a characteristic signature for each one. Through the assays the uranium compounds were classify by origin groups, as far as they are from different manufactured process and/ or origin. It was also possible to show the importance of a nuclear forensic database during an investigation of a nuclear forensic event.

Les explorations scientifiques menées depuis une quarantaine d’années ont permis d'identifier la diversité et la complexité des processus géologiques et géochimiques conduisant à la concentration des métaux dans les grands fonds océaniques. Les dépôts métallifères riches en hydroxydes de Fer et de Manganèse, tels que les encroûtements hydrogénétiques et hydrothermaux et les nodules polymétalliques, présentent des enrichissements variés en éléments d'intérêts économiques tels que le Ni, Cu, Co, Te, Pt et les Terres Rares. Bien que la minéralogie et la géochimie de ces dépôts aient été largement étudiées dans la littérature, les sources de métaux restent encore mal déterminées. Par conséquent, comprendre la géochimie de ces dépôts implique d’une part, de connaître les processus participant à leur genèse, et d’autre part d’avoir de meilleures connaissances sur les sources impliquées (par ex. flux continental et hydrothermal) et leur importance dans les grands cycles biogéochimiques des métaux dans les océans. Afin d’apporter de nouveaux éléments de réponse, notre approche a consisté à utiliser les compositions isotopiques des métaux comme traceurs biogéochimiques. Ce projet est structuré autour de deux hypothèses, (1) le développement et l’utilisation d’un nouveau outil géochimique que sont les isotopes du Ni pour tracer les sources et les processus d’enrichissements en métaux dans les dépôts métallifères océaniques ; (2) la combinaison de plusieurs systèmes isotopiques tels que Fe, Pb, Cu et Zn (et Ni) dans les encroûtements de fer-manganèse comme proxy de la composition isotopique de l’eau de mer profonde. Après avoir développé une méthode d’analyse des isotopes du Ni par MC-ICP-MS et estimé la variabilité isotopique du Ni dans les systèmes naturels par la caractérisation des grands réservoirs terrestres, nous avons évalué expérimentalement le fractionnementisotopique du Ni lors de son adsorption sur les oxyhydroxydes de Fe et Mn comme analogue à ce qui pourrait se produire dans les dépôts de Fe-Mn naturels. Les résultats indiquent que lors de l’adsorption du Ni, la phase solide est enrichie en isotopes légers par rapport à la solution avec des facteurs de fractionnement (Δ60/58Nimin/sol) variant de -1 ‰ pour la birnessite, -0.9 ‰ pour la goethite et -0.4 ‰ pour la ferrihydrite. A partir de ces résultats et d’autres études récentes, nous avons pu appuyer l’hypothèse selon laquelle d’un point de vue global la variabilité isotopique du Ni dans les dépôts métallifères océaniques riches en Fe et Mn s’explique par des processus d’enrichissement et de formation lors de l’incorporation des métaux dans les phases minérales de Fe et Mn plutôt que par des variations des compositions isotopiques des sources. Ainsi les encroûtements hydrogénétiques formés lentement à partir de l’eau de mer ne montrent pas de fractionnement isotopique du Ni, tandis que les dépôts hydrothermaux formés par des processus rapides liés aux apports hydrothermaux montrent des fractionnements du Ni plus importants. Puis, afin d’évaluer la possibilité d’utiliser les signatures isotopiques du Ni comme nouveaux traceurs paléocéanographiques, nous avons mené une étude comparative sur des encroûtements collectés dans le Pacifique Nord (proche de Hawaii) et le Pacifique Sud (proche de Tahiti). Dans ce contexte, les ncroûtements de fer-manganèse formés par précipitation très lente de l’ordre de quelques mm/Ma entre 1500 et 3000 m de profondeur, fournissent un enregistrement de plusieurs millions d’années des métaux dissous dans l’eau de mer. Après avoir réalisé une étude minéralogique et géochimique (éléments majeurs et traces) et calibré les taux de croissance des encroûtements, nous avons mesuré pour la première fois les compositions isotopiques du Ni, Fe, Zn, Cu et Pb sur la même série temporelle. / Scientific explorations implemented for around forty years allow to identifying the diversity and the complexity of geological and geochemical processes conducting to metals concentration on the deep seafloor. Fe- and Mn-rich metalliferous deposits such as hydrogenetic and hydrothermal ferromanganese (Fe-Mn) crusts and polymetallic nodules, present various enrichment in elements of economic interests like Ni, Cu, Co, Te, Pt and Rare Earth Elements. Although the mineralogy and geochemistry of these deposits have been largely studied in the literature, metal sources remain poorly determined. Accordingly, understanding the geochemistry of these deposits implies to know which processes are involved in their formation but also to have a better knowledge of the sources (e.g. the continental and hydrothermal fluxes) and their importance in the global oceanic metal biogeochemical cycles. In order to fill this gap, our approach consisted in using metal stable isotope compositions as biogeochemical tracers. This project is organized around two hypotheses, (1) development and utilization of a new geochemical tool, namely Ni isotopes, for tracing metal enrichment sources and processes in oceanic metalliferous deposits; (2) combination of several isotope systematics such as Fe, Pb, Cu, Zn (and Ni) in Fe-Mn crusts as proxies of the deep seawater isotope composition. Upon developing an analytical method for measuring Ni isotopes by MC-ICP-MS and estimating the Ni isotopes variability in natural systems through the characterization of terrestrial reservoirs, we experimentally evaluated Ni isotope fractionation during adsorption on Fe- and Mn-oxyhydroxides since similar processes may potentially occur in natural Fe-Mn deposits. Results indicate that after Ni adsorption, the solid phase is enriched in light Ni isotopes relatively to the solution with fractionation factors (Δ60/58Nimin/sol) varying from -1 ‰ for birnessite, -0.9 ‰ for goethite and -0.4 ‰ for ferrihydrite. These results, and other recent studies, strengthen our hypothesis according to which Ni isotopes variability in Fe- and Mn-rich metalliferous deposits can be explained by enrichment and formation processes during metal incorporation in Fe and Mn mineral phases rather than variations in the isotopic composition of the sources. Thus, hydrogenetic Fe-Mn crusts formed slowly from seawater dissolved metals do not show significant Ni isotope fractionation, whereas hydrothermal deposits formed by relatively rapid processes as a result of hydrothermal inputs exhibit important Ni isotope fractionation.

En cas de crise nucléaire impliquant des actinides, il est nécessaire de disposer de méthodes d’analyses rapides afin d’identifier les personnes contaminées. Elles sont réalisées dans les excreta (urines et selles). Les méthodes usuelles d’analyse de ces émetteurs alpha sont performantes, mais elles sont longues et difficiles à mettre en œuvre et, de fait inadaptées à une situation de crise. Ce travail de thèse a donc consisté à développer une méthode d’analyse rapide des actinides dans l’urine par couplage entre une colonne à base de dérivés de calix[6]arène hydroxamique imprégné et un spectromètre de masse couplé à un plasma induit (ICP-MS). L’étude de la spéciation des actinides dans l’urine minéralisée a permis de mieux comprendre les réactions mises en jeu et de maîtriser leur extraction sur la colonne calix[6] arène. Un protocole a pu être élaboré, aboutissant à l’extraction simultanée des trois actinides à pH ≈ 5 puis à leur co-élution avec H3PO4 à 0,25 mol.L-1 avec des rendements de récupération moyens de 56 %, 74 % et 85 % pour U, Pu et Am respectivement. La colonne calix[6]arène a ensuite été couplée l’ICP-MS quadripolaire et les paramètres chromatographiques (diamètre de colonne, débit d’extraction et d’élution) optimisés. Ce système de couplage permet d’atteindre des limites de détection dans l’urine inférieures à 0,5 mBq.L-1 pour 238U et 243Am et inférieure à 5 mBq.L-1pour le 239Pu et 241Am, pour une durée totale d’analyse d’environ 6 heures. Ces performances ont démontré que cette méthode de couplage pourrait être utilisée en situation de crise. / In the event of a nuclear crisis, involving actinides (U, Pu, Am) it is important to have fast analysis methods available in order to identify people that could be contaminated. Usually, they are performed in urine or faeces. Even though, analytical methods used with alpha detection are reliable they are lengthy and tedious to set up. This work consisted in developing an on-line coupling method between a calix[6]arene-based chromatography column and an inductively coupled plasma mass spectrometer (ICP-MS). To do so, a speciation study of actinides in mineralised urine was developed to understand the chemical equilibria happening during the actinides extraction. A protocol was elaborated to extract simultaneously all three actinides at pH ≈ 5, then co-elute them with 0.25 mol.L1 H3PO4. Recovery was 56 %, 74 % and 85 % for U, Pu and Am respectively. The column was then coupled to the ICP-MS. A parameter study helped defining mineralisation duration, extraction and elution flow-rates. It was then possible to propose an on-line coupling system allowing reaching detection limits lower than 0.5 mBq.L-1 for 238U and 243Am and lower than 5 mBq.L-1 for 239Pu and 241Am, for analysis duration lower than 6 hours. These analytical performances show the interest of this technique for a use in a nuclear crisis situation.

O arsênio (As) é um elemento não essencial ao homem, encontrado na natureza nas formas inorgânicas (As-i) e orgânicas (As-o). As espécies inorgânicas, arsenito e arsenato (As3+ e As5+), são as mais tóxicas, podendo interferir em reações bioquímicas, estado redox das células, formação de trifosfato de adenosina (ATP) e gerar danos oxidativos, ocasionando proliferação celular e câncer. O As-i pode sofrer metilação no organismo e no ambiente, gerando metabólitos que são menos reativos com componentes do tecido e mais facilmente excretados na urina, principalmente ácido monometilarsônico (MMA) e ácido dimetilarsínico (DMA). O As-i é encontrado no arroz (Oryza sativa L.), principalmente quando o cultivo ocorre pelo método irrigado, que leva a uma maior mobilização de elementos presentes no solo. Neste estudo, foram avaliadas 6 diferentes cultivares brasileiras de arroz quanto à predileção pela captação de As (EPAGRI 109, EPAGRI 108, SCS BRS Tiotaka, SCS 114 Andosan, Maranhão e Cáqui). Para cada cultivar foram plantados grupos controles (não expostos, n=4) e expostos (n=4). No grupo exposto, para cada kg de solo, foram adicionados 10 mg de As5+. Nos grupos controle não adicionou-se As5+, sendo submetidos às mesmas condições de solo, irrigação, temperatura e umidade. Após a completa maturação das plantas foram feitas determinações de As total (As-t) em raízes, solo, colmos e grãos por espectrometria de massas com plasma indutivamente acoplado (ICP-MS) e a especiação química de As nos grãos foi feita por HPLC-ICP-MS. Uma elevada capacidade de captação do As foi observada na seguinte ordem crescente: grãos<colmos<solo<raízes, sendo as concentrações médias dos grupos controle de 0,06; 0,32; 3,29 e 0,65 mg kg-1 e nos grupos expostos com médias de 0,54; 5,96; 13,5 e 95,48 mg kg-1. EPAGRI 108 foi a cultivar que menos acumulou As-t nos grãos, tanto nos grupos controle (0,05±0,005 mg kg-1) quanto nos grupos expostos (0,36±0,08 mg kg-1) apresentando também menores fatores de transferência (FTsolo-grão, FTraíz-grão, FTcolmo-grão) e concentrações de As-o nos grupos controle (0,015 mg kg-1) e expostos (0,13 mg kg-1). Entre as cultivares de arroz branco, Andosan (exposto) foi a que acumulou maiores quantidades de As-t (0,515±0,15 mg kg-1) e de Aso (0,37 mg kg-1 ou 72% do As-t) nos grãos. Esta mesma cultivar, entre os grupos controle, foi uma das que apresentou maiores porcentagens de As-i (65%) em relação ao As-t. EPAGRI 109 (controle) foi a cultivar de arroz branco com maior As-t e As-i no grãos (0,07±0,008 e 0,04 mg kg-1 respectivamente) e maior FTsolo-grãos (0,216). Nas plantas expostas a 10 mg Kg-1 As5+ no solo foi observada uma correlação positiva entre As-t (solo) x As-t e As-o (grãos) evidenciando o aumento da captação de As e transporte de As-o para as partes aéreas. Os elementos essenciais Co e Mn diminuíram significativamente em alguns cultivares sob alta exposição apresentando correlação negativa As-t (raíz) x Co (grãos). Os elementos tóxicos Cd e Pb, sob alta exposição ao As foram em geral menos captados pela planta. / Arsenic (As) is a nonessential element to man, found in the environment in inorganic (As-i) and organic forms (As-o). Inorganic species, arsenite and arsenate (As3+ and As5+) are the most toxic, and may interfere in biochemical reactions, cellular redox status, formation of adenosine triphosphate (ATP) and generate oxidative damage leading to cell proliferation and cancer. As-i can be methylated in the body and in the environment generating metabolites which are less reactive with components of organisms and more easily excreted in the urine, mainly monomethylarsonous acid (MMA) and dimethylarsinous acid (DMA). As-i is found in rice (Oryza sativa L.), especially when the crop is flooded, which leads to greater mobilization of elements present in the soil. In this study, Brazilian rice varieties were evaluated and the predilection for As uptake in 6 different cultivars (EPAGRI 109, EPAGRI 108, BRS Tiotaka SCS, SCS 114 Andosan, Maranhão and Cáqui). For each cultivar it were planted controls (untreated, n = 4) and exposed (n = 4). In the group exposed, for each kg of soil was added 10 mg of As5+. Control groups were not added As5+, being submitted to the same conditions of soil, irrigation, temperature and humidity. After complete plant maturation were made determinations of the total Arsenic (As-t) in soil, roots, shoots and grains were performed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and the chemical speciation of the grains was performed by HPLC-ICP-MS. A high As uptake ability was observed in the following order: grain<shoot<soil<roots, and the average concentrations of control groups were 0.06; 0.32; 3.29 and 0.65 mg kg-1 and the average exposed groups were 0.54; 5.96; 13.5 and 95.48 mg kg-1. EPAGRI 108 was the cultivar less accumulated As-t both control groups (0.05 ± 0.005 mg kg-1) as the exposed group (0.36 ± 0.08 mg kg-1) also presenting the lowest FTsoil-grain, FTroot-grain, FTshoot-grain, concentrations of As-o in the control (0.015 mg kg-1) and exposed group (0.13 mg kg-1). Among the white rice cultivars, Andosan (exposed) accumulated larger amounts of As-t (0.515 ± 0.15 mg kg-1) and As-o (0.37 mg kg-1 or 72% As-t) in grains. This same cultivar was the one who had higher percentages of As-i (65%) compared to As-t, between the control group. EPAGRI 109 (control) was the white rice cultivar with high As-t and As-i in grain (0.07±0,008 and 0,04 mg kg-1 respectively) between the control group and higher FTsoil-grain (0,216). In high As exposure, it was observed a positive correlation between As-t (soil) x As-t and As-o(grains) highlighting the increased As uptake and the transport of As-o to the aerial parts. The essential elements Co and Mn decreased significantly in some cultivars under high exposure and showed negative correlation between As-t (root) x Co (grain). Toxic elements, Cd and Pb under high As exposure were generally less uptake by plant

Ce manuscrit présente les premiers résultats d'études élémentaires et isotopiques du Zn, du Sr et du Pb, réalisées dans les principaux types d'échantillons liés aux gaz volcaniques (gaz, sublimés, eaux thermales, roches), ainsi que deux nouvelles méthodologies d'échantillonnage des émanations volcaniques. Les variations isotopiques du Zn observées au Merapi suggèrent que les processus de changement de phase (fluides/solides) peuvent provoquer des fractionnements isotopiques significatifs des éléments trace métalliques. L'étude couplée Sr/Pb réalisée à Vulcano indique que les compositions en éléments trace métalliques des fumerolles et des eaux thermales sont influencées par les sources naturelles et anthropiques. Ce travail a aussi permis la mise au point de nouvelles méthodologies d'échantillonnage et d'analyse des gaz et des panaches volcaniques, permettant d'accéder à la composition chimique complète de ces manifestations gazeuses de manière simple et efficace.

Il presente studio affronta il tema della rintracciabilità alimentare di prodotti agroalimentari, analizzando il caso del pomodoro da industria, cercando di trovare degli indicatori chimici (markers) che siano in grado di discriminare prodotti provenienti da aree geografiche differenti. Viene quindi affrontato il tema della tipicità che consiste nel legame esistente tra l'alimento e il territorio nel quale viene prodotto. I parametri chimici che vengono indagati sono elementi appartenenti al gruppo delle terre rare (o serie dei lantanidi) e dei rapporti isotopici degli elementi pesanti quali lo Stronzio. La determinazione analitica delle terre rare nel pomodoro è stata effettuata con ICP-MS e HR-ICP-MS (Inductivity Coupled Plasma Mass Spectrometry, Hight Resolution Inductivity Coupled Plasma Mass Spectrometry). I rapporti isotopici dello Stronzio sono stati determinati con la tecnica TIMS (Thermal-Ionization Mass Spectroscopy) Le tecniche analitiche utilizzate hanno permesso di determinare con precisione e accuratezza tutti gli elementi appartenenti al gruppo delle terre rare nei comparti della pianta di pomodoro e nel terreno. La misura dei rapporti isotopici dello stronzio ha permesso di discriminare prodotti provenienti da aree geografiche differenti. / Food traceability systems have a broader scope and aim to document the history of a product along the entire production chain from primary raw materials to the final consumable product. the present work has looked at ways of detecting rare earth and strontium isotope abundance ratios. It is fundamental to have knowledge of the REE concentrations of the soil where the plants are grown and the distribution of the REEs in the different parts of the plants: roots, stems, leaves, and berries. Tomato is one of the most widely grown vegetables in the world. The analytical procedure, using inductively coupled mass spectrometry (ICP-MS) and HR-ICP-MS proved to be suitable for the determination of REEs in plants and soil, and was validated using certified samples. Strontium isotope ratio is an important parameter allowing the discrimination of foods coming from different geographical origins. Very high precision is usually reached with Thermal Ionization Mass Spectrometer (TIMS). The analytical techniques have permitted to determine all REEs elements in compartments of tomato plants. The described method point out the measurement of the 87Sr/86Sr ratio as a very important parameter for the discrimination of tomato from different geographical origins, even if the present experimental work treating a limited number of samples have to be considered as a “first step”.

Die Strukturen der Erdalkalimetall-Subnitride (EA2N) von Calcium, Strontium und Barium ermöglichen mit ihrem schichtartigen Aufbau aus EA6N-Oktaedern Intercalationsreaktionen. Die Redox-Intercalation von Stickstoff in Sr2N wurde an Einkristallen untersucht. Nur durch eine drastische Erhöhung des Reaktionsgasdruckes im Vergleich zu den Reaktionen an mikrokristallinen Proben wurde die Intercalation der Diazenidionen in die Kristalle zu Sr4N3 und SrN möglich. Für eine analoge Intercalation von Wasserstoff in Sr2N konnten die Reaktionsbedingungen dahingehend optimiert werden, dass erstmals phasenreines Strontiumnitridhydrid (Sr2N)H bzw. deuterid (Sr2N)D erhalten wurde. Anhand von Intercalationsreaktionen mit Sr2N Kristallen konnte gezeigt werden, dass der Intercalationsprozess, erkennbar an der deutlichen Farbänderung von schwarz nach bersteinfarben, von außen nach innen fortschreitet. Als Methode zur räumlich aufgelösten Analyse wurde die Laserablation, in Kombination mit einem ICP - Massenspektrometer (LA-ICP-MS) verwendet. In der Literatur beschriebene Quantifizierungsstrategien wurden auf die Anwendbarkeit für die gegebene Fragestellung untersucht. Mit der ortsaufgelösten Analyse von Einkristallen konnte gezeigt werden, dass die Intercalation von Stickstoff in die Kristalle kontinuierlich von den Kanten zur Kristallmitte fortschreitet.

Neste estudo foi determinado o conteúdo de metais em adoçantes dietéticos de mesa, consumidos por um número crescente de pessoas preocupadas em manter a forma física e restringir o nível calórico da dieta havendo ou não recomendação médica. Foram coletadas 26 amostras de adoçantes dietéticos distribuídos no mercado de São Paulo, em uma grande variedade de apresentações, produtos, composições e marcas. Como a composição é dependente da produção, esta análise é indispensável ao controle da qualidade e relevante à saúde do consumidor. A Espectrometria de Emissão Óptica com Fonte de Plasma Indutivamente Acoplado (ICP OES) com vista axial, mostrou-se adequada determinação dos macronutrientes Na, K, Ca, Mg e dos microelementos essenciais Fe, Cu, Zn, Cr, Mn e Se, dos potencialmente tóxicos AI, Ni, As, Cd e Pb em adoçantes sólidos e líquidos, atendendo as exigências da legislação brasileira. Assim, foi realizado um estudo comparativo entre as determinações utilizando as metodologias clássicas de pré-tratamento da amostra, como o resíduo de cinzas, a dissolução ácida com aquecimento por microondas com o procedimento sem tratamento prévio das amostras, visando facilitar a análise, uma vez que esta é a etapa que mais consome tempo e esforços. A determinação simultânea do espectro favoreceu a análise, uma vez que 74 comprimentos de onda puderam ser selecionados sem aumento no tempo ou no custo de análise, auxiliando na seleção de 36 linhas analíticas mais adequadas (livre de interferências) à determinação sem tratamento prévio da amostra. Nenhuma amostra de adoçante excedeu o valor recomendado para o somatório dos contaminantes inorgânicos (Aspartame < 10 &#181;g g-1 e Sacarina < 20 &#181;g g-1). No entanto, 6 marcas de adoçantes em pó excederam o valor limite da legislação para As (1,0 &#181;g g-1), excederam o valor para Cr total (0,1 &#181;g g-1) e 2 marcas de adoçante líquido excederam o valor para Ni (0,1 &#181;g g-1). Mostrando que os adoçantes em pó apresentam (&#8776;5 &#181;g g-1) níveis maiores de metais potencialmente tóxicos que os adoçantes líquidos (&#8776;2,O &#181;g mL-1). / The metal content in artificial sweetener usually consumed by a growing population concerned to keep body shape and to restrict the diet caloric content, by medical recommendation or not, was measured. The samples were 26 artificial sweeteners available at São Paulo\'s market, under different forms, and several suppliers, with various sweetener composition, and brands. Because the composition depends on manufacture factors, this analysis is mandatory for quality control and relevant for the user health. Inductively coupled plasma atomic emission with axial view has demonstrated to be an appropriated technique to determine the macronutrient content, such as Na, K, Ca, Mg and essential microelements such as Fe, Cu, Zn, Cr, Mn and Se, besides the potentially toxic elements such as AI, Ni, As, Cd and Pb in solid and liquid sweeteners in accordance with to the Brazilian regulation. It was also performed a comparative study of the sample preparation methodology, using classical sample pretreatment, such as burning to ashes, and acid dissolution with microwave heating and a procedure without prior sample treatment (dissolution and/or convenient dilution), aiming at facilitating the analysis of dietetic sweetener because this step is the most time and labor consuming. The analysis was simplified using the simultaneous spectra acquisition, once 74 wavelengths were selected without time or cost increase, and helping the identification of 36 appropriate analytical lines (free from interferences) to apply to the samples determination without prior treatment. None sweetener exceeded the recommended value of inorganic contaminant (for aspartame samples the value was below 10 &#181;g g-1 and for saccharine samples that was below 20 &#181;g g-1). However, 6 brands of artificial sweetener in powder exceeded the legislation limit value for As (1.0 &#181;g g-1), and other 7 brands exceeded the Cr recommended maximum value (0.1 &#181;g g-1). Other 2 brands of Iiquid sweetener exceeded the Ni recommended maximum value. Therefore, for ali samples, the artificial sweetener in powder presented higher levels of potentially toxic metais (&#8776;5&#181;g g-1) than those in a Iiquid presentation (&#8776;2.0 &#181;g mL-1).