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Small to large molecule speciation: Metallomics approaches stretch the horizonsKroening, Karolin January 2010 (has links)
No description available.
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Elemental speciation and trace metal analysis using chemical separations interfaced to inductively coupled plasma - mass spectrometryDay, Jason A. 11 October 2001 (has links)
No description available.
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A Novel Trace Elemental Analysis of Potassium PhosphatesRohman, Joshua 28 June 2016 (has links)
No description available.
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The investigation of high performance techniques and application to complex matrices using inductively coupled plasma spectrometry and the impact of urbanization on the Scioto River systemRabb, Savelas 02 March 2005 (has links)
No description available.
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Improving the Quality of LiDAR Point Cloud Data for Greenhouse Crop MonitoringSi, Gaoshoutong 09 August 2022 (has links)
No description available.
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Varifrån kommer metallerna i Vallentunasjön? / Sources of the metals in Lake VallentunaBitar, Mriana January 2016 (has links)
No description available.
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Study of Optimal Deposition Conditions for an Inductively Coupled Plasma Chemical Vapour Deposition (ICP-CVD) SystemZhang, Haiqiang January 2005 (has links)
No abstract provided. / Thesis / Master of Engineering (MEngr)
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Les aérosols de pollution en zone urbaine et industrielle sous influence marine. Physico-chimie des particulesRimetz, Juliette 06 December 2007 (has links) (PDF)
Les grands ports de marchandises sont généralement proches de zones urbaines très peuplées et de zones industrielles comportant des raffineries de pétrole, des complexes métallurgiques, des cimenteries, et des transports par rail, par route et par mer. Ces activités font des domaines portuaires des sources très importantes de pollution de l'air. Les mesures de concentrations de NO<sub>x</sub>, SO<sub>2</sub>, O<sub>3</sub> et des constituants chimiques de la matière particulaire (PM) ont été effectuées en 2005 et 2006 dans l'agglomération du port de Dunkerque dans le cadre de l'Institut IRENI. Dans des conditions de dépression atmosphérique, les vents dominants préservent l'air de la zone urbaine des émissions de la zone d'activité. Par contre dans des conditions anticycloniques, la faible dispersion ainsi que les phénomènes de brise de mer concentrent les émissions locales. Les analyses chimiques effectuées sur des échantillons de PM prélevées en fonction du diamètre aérodynamique (D<sub>a</sub>) des particules montrent que les ions (Na<sup>+</sup>, NH<sub>4</sub><sup>+</sup>, Cl<sup>-</sup>, NO<sub>3</sub><sup>-</sup>, SO<sub>4</sub><sup>2</sup>), les éléments métalliques (Fe, Zn, Pb, Cd, etc...) et les composés organiques (EC, OC) sont associés à des particules sub- et/ou supermicroniques. Les imageries Raman et d'émission X (MEBE-EDS) sont obtenues sur des particules individuelles des fractions 1
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Spéciation du mercure dans les produits de la pêche par double dilution isotopique et chromatographie en phase gazeuse couplée à un spectromètre de masse à plasma induit (GC-ICP-MS) / Mercury speciation in seafood by double isotope dilution and gas chromatography inductively coupled plasma mass spectrometry (GC-ICP-MS)Da fonseca Clemens, Stéphanie 15 September 2011 (has links)
Le mercure est un contaminant présent dans l'ensemble des compartiments de l'environnement et l'homme y est directement exposé via l'alimentation. Actuellement, les organismes gouvernementaux évaluent la sécurité des produits alimentaires en se basant essentiellement sur la concentration totale de cet élément. Cependant, la toxicité du mercure dépend, entre autre, de l'espèce absorbée (dont le méthylmercure, sa forme la plus toxique). Par conséquent, l'analyse de spéciation, c'est à dire la détection et quantification des différentes formes chimiques de cet élément, présente un intérêt croissant. Le principal objectif de ce projet a donc été de développer et de valider, sous assurance qualité, une méthode sensible et d'une grande exactitude, basée sur l'utilisation de la dilution isotopique. Elle sera par la suite appliquée comme méthode de référence par l'agence pour l'analyse en spéciation du mercure dans les produits de la pêche afin de permettre une meilleure évaluation des risques encourus par le consommateur. La première partie de ce travail a porté sur l'étude du cycle biogéochimique du mercure et de l'état de l'art des diverses méthodes de préparation de l'échantillon, de séparation et de quantification du Hg dans les matrices biologiques, afin d'émettre des choix analytiques. Ainsi, les principaux composés mercuriels susceptibles d'être retrouvés dans les produits de la pêche (le méthylmercure et le mercure inorganique) ont été déterminés par couplage GC-ICP-MS et une quantification par dilution isotopique. La seconde partie des travaux a été consacrée à l'optimisation de la méthode de préparation des échantillons et de la technique de quantification. Ces travaux sur différents matériaux de référence certifiés ont montré que des modifications de la distribution naturelle de l'échantillon pouvaient survenir dès l'étape d'extraction, préconisant un marquage isotopique avant extraction solide-liquide par digiPREP des espèces mercurielles et dérivation par propylation par le tétrapropylborate de sodium et agitation rotative. Les résultats expérimentaux ont été traités par dilution isotopique simple et multiple. Les teneurs obtenues ont été similaires, pour l'ensemble des matrices analysées, montrant que peu ou pas de transformation inter-espèces surviennent au cours de la procédure analytique. Une quantification par double marquage isotopique et dilution isotopique simple a donc été conservée. L'évaluation des critères analytique a démontré que la méthode est validée pour la spéciation du mercure dans les produits de la pêche, selon les normes françaises AFNOR NF V03-110 de 1998 et de 2010. La dernière partie des travaux a porté sur l'application de la méthode validée à la spéciation du mercure dans des échantillons biologiques réels, ainsi qu'à la participation à plusieurs essais interlaboratoires d'aptitudes organisés par le CSL-FAPAS sur un échantillon de thon en conserve et par l'IRMM sur le matériau IMEP-109 de homard. / Mercury is a contaminant which is found in all compartments of the environment and to which human beings are directly exposed when eating food. Government agencies assess the safety of food products by using total mercury concentrations. However, its toxicity depends on the species absorbed (among which methylmercury is its most toxic form). Therefore, the analysis of speciation, i.e. detection and quantification of different chemical forms of this element, is of high interest. The main objective of this project was to develop and validate, under quality assurance, a sensitive and highly accurate method, based on the use of isotope dilution. This method will then be applied as a reference method by the agency for speciation analysis of mercury in seafood, in order to better assess risks to the consumer. The first part of this work focused on the biogeochemical cycle of mercury and the state of art of the various methods of sample preparation, separation and quantification of Hg in biological matrices in order to make analytical choices. Thus, mercury compounds (methyl mercury and inorganic mercury) were determined by gas chromatography (GC) coupled with an inductively coupled plasma mass spectrometer (ICP-MS) and quantified by isotope dilution. The second part of the work was dedicated to the optimization of the method of sample preparation and the quantification technique. The work was made on different certified reference materials and showed that changes of the natural distribution of the sample could occur during the extraction step. Therefore, isotopic tracers had been added to the sample before this step. Mercury species were extracted by a solid-liquid extraction by using a digiPREP and derivated by propylation using tétrapropylborate the sodium and a rotary agitation. Data were treated by simple and multiple isotope dilution. Achieved concentrations were similar for all analyzed matrices. Results showed that inter-species transformation hardly occurred during the analytical procedure. This was the reason why the use of two isotopic tracers for quantification by simple isotope dilution was kept. To end, the method was validated for the speciation of mercury in seafood, in respect with the French norms AFNOR NF V03-110 of 1998 and 2010. Finally, the work ended with the applicability of the validated method for mercury speciation analysis in real biological samples and our participation in several inter-laboratory proficiency tests organized by the CSL-FAPAS on a sample of tuna and by the IRMM on the material IMEP-109 (lobster).
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[en] STUDIES ON THE ORIGIN AND TRANSFORMATION OF SELENIUM AND ITS CHEMICAL SPECIES ALONG THE PROCESS OF PETROLEUM REFINING / [pt] ESTUDOS SOBRE A ORIGEM E TRANSFORMAÇÃO DE SELÊNIO E DE SUAS ESPÉCIES QUÍMICAS AO LONGO DO PROCESSO DE REFINO DO PETRÓLEOCIBELE MARIA STIVANIN DE ALMEIDA 15 September 2008 (has links)
[pt] Diferentes métodos espectrométricos de análise, incluindo
ICP OES, ICP-DRCMS e Q-ICPMS com técnicas hifenadas
(geração de hidreto, vaporização eletrotérmica ou
cromatografia de íons), foram aplicados na caracterização
química de 16 óleos e 41 amostras de efluentes aquosos de
uma refinaria de petróleo. O objetivo específico
deste estudo foi o de entender o comportamento do selênio
(Se) e de suas espécies químicas ao longo do processo de
geração e tratamento dos efluentes desta unidade
industrial. A caracterização química multielementar das
amostras por ICP-MS revelou uma composição muito complexa
da maioria deles, com altas salinidades e potenciais
interferentes espectrais e não espectrais presentes. Por
isso, foi necessária uma reavaliação crítica das técnicas
analíticas para a determinação de Se e de suas
espécies. As técnicas de ICP-DRC-MS, utilizando CH4 como
gás de reação, e de ETVICPMS mostraram o seus potencial
para a determinação de Se com melhores limites
de detecção (cerca de 0,05 ug L-1 para ambas), mas também
as suas limitações na análise de efluentes com altas
salinidades. Nas 16 amostras de petróleo analisadas,
verificou-se uma grande variabilidade nas concentrações de
Se total, cobrindo uma faixa de < 10 ug kg-1 até 960 ug kg-
1, a qual poderia explicar também a carga muito
variável deste elemento nos efluentes das diferentes
unidades de tratamento. As maiores concentrações de Se
total foram encontradas nas águas ácidas, com
concentrações de até 1714 ug L-1. Confirmou-se a
predominância de SeCN - na maioria das amostras analisadas,
mas observaram-se também outras espécies com tempos de
retenção diferentes das espécies Se(IV), Se(VI) e SeCN-,
especialmente nos efluentes da estação de tratamento de
despejos industrais (E.T.D.I.). Em amostras ácidas,
identificou-se Se coloidal (Seº) formado pela decomposição
de SeCN-, ou de outras espécies pouco estáveis nestas
condições. Experiências de bancada com soluções de
SeCN- apoiaram esta hipótese. Foi constatada, que o perfil
de especiação de amostras coletadas num mesmo local de
processamento, mas em épocas diferentes, pode variar
significativamente, o que torna difícil a comparação de
dados obtidos neste trabalho com os de outros autores. / [en] Different spectrometric methods of analysis, including ICP
OES, ICP-DRC-MS and
Q-ICP-MS, the latter hyphenated to hydride generation,
eletrothermal vaporization or ion
chromatography have been appliesd to the chemical
characterization of 16 crude oils
and 41 effluents samples from a petroleum refinery. The
specific objective of this study
was to get information on the behavior of selenium (Se) and
its species along the
different processes of generation and treatment of the
effluents.Multielemental
characterization of effluents by ICP-MS revealed a complex
composition of most of them,
with high salinity and potential spectral and non spectral
interferents present. For this
reason, a critical reassessment of the analytical
techniques for the determination of total
Se and its species was necessary. DRC-ICP-MS and ETV-ICPMS,
using CH4 as cell
reaction gas, showed their potential for the determination
of Se with better detection
limits (about 0,05 ug L-1), but also their limitations for
the analysis of effluents with high
salinity. A large variability in the concentration of Se
was observed in the 16 analysed
crude oil samples (< 10 ug kg-1 Se until up to 960 ug kg-1),
which may explain also the
varying concentrations measured in the effluents. Highest
concentrations of selenium
were measured in samples from the treatment unit for acid
waters (up to 1.714 ug L-1).
The predominance of selenocyanate (SeCN-1) was confirmed in
most of the effluent
samples analysed, but also several other species with
retention times different from
Se(IV), Se(VI) e SeCN - were observed, especially in samples
from the treatment plant.
Colloidal Se (Seº) was identified in acid waters, probable
formed by decomposition of
SeCN - or other unstable species under these conditions.
Laboratory experiments with
selenocyanate solutions confirmed this hypothesis. The
speciation profile of samples
collected at the same point, but at different time
intervals, showed significant variations,
not allowing easy comparison of the results obtained in
this work with those of other
authors.
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