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Rodrigues, Jairo Lisboa. "Avaliação de técnicas acopladas à espectrometria de massas com plasma (ICP-MS) visando o fracionamento e a especiação química de mercúrio em sangue e plasma." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/60/60134/tde-13082010-100725/.
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O Mercúrio (Hg) é um dos mais tóxicos poluentes do meio ambiente. Ele existe basicamente em três formas: Mercúrio elementar (Hg0), ou Hg metálico, mercúrio inorgânico (Hg-i), principalmente o cloreto mercúrico e o mercúrio orgânico (Hg-o), representado principalmente pelo metilmercúrio (MeHg) e etilmercúrio (EtHg), sendo que as formas orgânicas do Hg são mais tóxicas. Sendo assim, é de suma importância que se tenha métodos de fracionamento (Hg t, Hg-i e Hg-o pela diferença) e de especiação de mercúrio (Hg-i, MeHg, EtHg) para diferenciação das espécies de mercúrio em matrizes biológicas. Neste sentido, o presente trabalho teve como objetivos o desenvolvimento de três métodos analíticos rápidos, simples e sensíveis para: i) fracionamento entre Hg-t e Hg-i em sangue/plasma (Hg-o pela diferença) utilizando sistema de geração de vapor frio em linha com ICP-MS (CV ICP-MS); ii) especiação de Hg em amostras de sangue e plasma utilizando o acoplamento HPLC-ICP-MS; iii) especiação de Hg em amostras de sangue utilizando o acoplamento GC-ICP-MS. No método de fracionamento de mercúrio foi feito o preparo de amostras utilizando hidróxido de tetrametilamônio (TMAH) à temperatura ambiente. No método de especiação por HPLC-ICP-MS foi feita a extração das espécies utilizando banho ultrassônico, ao passo que no método GC-ICP-MS foi feita a extração das espécies assistida por microondas. O método CV ICP-MS foi comparado com a geração de vapor utilizando absorção atômica (CV AAS) não tendo diferença estatística entre os dois métodos. Para validação dos métodos foi utilizado Material de Referência Certificado (NIST 966) e outros Materiais de Referência. Os métodos foram aplicados para análise de amostras de sangue de populações Ribeirinhas da Amazônia brasileira expostas ao mercúrio. Os métodos demonstraram ser simples e rápidos, podendo facilmente serem implantados em rotina de laboratórios clínicos.<br>Mercury (Hg) is one of the most toxic environmental pollutants. It exists primarily in three forms: elemental mercury (Hg0), or metallic mercury, inorganic mercury (Hg-i), particularly mercuric chloride and organic mercury (Hg-o), mainly represented by methylmercury (MeHg) and ethylmercury (EtHg), and the organic forms of mercury are more toxic than the inorganic ones. Then, it is very important the development of simple and fast methods for mercury fractionation (T-Hg, Hg-i and Hg-o by the difference) or speciation (Hg-i, MeHg, EtHg) in biological samples. Then, the aims of this work were to evaluate three analytical methods for: i) mercury fractionation in blood/plasma samples (Hg-t, Hg-i and Hg-o by difference) by using a ICP-MS on line coupled to a cold-vapor generation system (CV ICP-MS), ii) Hg speciation in blood and plasma by using LC coupled to ICP-MS; iii) Hg speciation in blood samples with the use of GC coupled to ICP-MS. For the fractionation method, samples were previously incubated with tetramethylammonium hydroxide (TMAH) at room temperature. On the other hand, for the speciation of Hg in blood/plasma by using HPLC-ICP-MS the extraction of Hg species was carried out with the use of ultrasonic energy. For the speciation methodology with GC-ICP-MS the extraction of Hg species was carried out with the use of microwave-assisted extraction. Validation of the proposed methods were evaluated based on the analysis of the SRM NIST 966 and ordinary blood samples collected from riparians living in the Brazilian Amazon exposed to mercury. In general the proposed methodologies proved to be simple, fast and easily applied in routine analysis by clinical laboratories.
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Demuth, Natascha. "Massenspektrometrische Isotopenverdünnungsanalyse (MSIVA) als Validierungsmethode für Bestimmungen von Methylquecksilber mittels GC-ICP-MS." [S.l. : s.n.], 2001. http://ArchiMeD.uni-mainz.de/pub/2001/0132/diss.pdf.
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Silva, Elidiane Gomes da 1983. "Combinação de técnicas para a determinação de espécies de selênio." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/248605.
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Orientadores: Marco Aurélio Zezzi Arruda, Fábio Augusto<br>Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química<br>Made available in DSpace on 2018-08-21T15:26:25Z (GMT). No. of bitstreams: 1
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Previous issue date: 2012<br>Resumo: No Capítulo 1, é proposta a combinação das técnicas de microextração em fase sólida com a espectrometria de absorção atômica em forno de grafite para extração de Se(IV) derivado, seguida de detecção por GC-MS. O método é aplicado com sucesso na determinação de Se total em materiais de referência certificado (BCR-414 and SRM 1643e), sendo obtidas recuperações de 97% para a água (SRM 1643e) e 101% para o plâncton (BCR-414). O método também é aplicado para determinação de selênio em amostra de medicamento manipulado a base de quelato de selênio. No Capítulo 2, a técnica de HPLC com troca aniônica acoplada a ICP-MS, é usada para identificação e determinação de quatro espécies de selênio (Se(IV), Se(VI), selenometionina e selenocistina) em amostras biológicas (plâncton, castanha-do-pará, urina e folhas de girassol). A extração das espécies, presente em plâncton (BCR-414), castanha-do-pará e folhas de girassol, é realizada com água, e um teste de simulação de digestão gastrointestinal também é aplicado para identificar as espécies de selênio bioacessíveis em castanha do Pará. O Se(IV) é a principal espécie extraída no plâncton, com maior concentração de selênio no extrato. A castanha-do-pará possui, principalmente, selenocistina e selenometionina, sendo que somente a selenometionina é identificada como bioacessível. O estudo de especiação de selênio por HPLC-ICP-MS sugere a presença de selenocistina em urina de homens e mulheres. As folhas de girassol, de plantas cultivadas com solução de selenito apresentam um maior número de espécies de selênio, em comparação a planta controle<br>Abstract: In Chapter 1, the combination of the techniques of solid phase microextraction with atomic absorption spectrometry graphite furnace is proposed, using an SPME fiber device and graphite furnace (GF) for extracting Se compounds. The extracted compounds are separated and detected by GC-MS. The method is successfully applied to the total Se determination in certified reference materials (BCR-414 and SRM 1643e). The SPME-GF method combined with GC-MS is also applied to the determination of total selenium in a commercial drug sample (selenium chelate). In Chapter 2, the anion-exchange HPLC technique coupled to ICP-MS is used for identification and determination of four selenium species (Se(IV), Se(VI), selenomethionine and selenocystine) in biological samples (plankton, Brazil nuts, urine and sunflower leaves). The extraction of the species is carried out using water for plankton (BCR-414), Brazil nuts and sunflower leaf. A simulated gastrointestinal digestion is also used to identify bioaccessible selenium in Brazil nuts. The Se(IV) is the predominant specie in the plankton, with the highest selenium concentration in the extract. The Brazil nuts contain selenomethionine and selenocystine species, but only selenomethionine is identified as bioaccessible. The study of selenium speciation by HPLC-ICP-MS suggests the presence of selenocystine in the urine of women and men. The sunflower leaves of plants cultivated with selenite have a higher number of selenium species compared to the control plants<br>Doutorado<br>Quimica Analitica<br>Doutora em Ciências
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Diaz-Bone, Roland Arturo. "Untersuchung metall(oid)organischer Verbindungen nach biologischer Abfallbehandlung mittels einer neu entwickelten GC-ICP-MS-Methode." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=98253566X.
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Kresimon, Jutta. "Untersuchung humaner Körperflüssigkeiten und Ausscheidungsprodukte auf metall- und metalloidorganische Verbindungen mittels HG/LT-GC/ICP-MS." [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=968638465.
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Haas, Karsten. "Evaluation of GC-ICP-MS method for the determination of volatile metal(loid) compounds in environmental gas samples." Thesis, University of Aberdeen, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430377.
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The aim of this study is to perform multielemental determinations of volatile organometal(loid) compounds (VOMs) in environmental gases such as landfill gas and sewage sludge fermentation gases. The analytical method focuses on the on-line coupling of capillary GC with ICP-TOF-MS and provide excellent separation as well as sensitive element selective detection. It involves a cryotrapping step for these (VOMs) such as hydrides, methylated and permethylated species of e.g. As, Sb, Sn, Bi, Hg, Pb etc. In-house standards were generated in Tedlar<sup>® </sup>bags and a classical external calibration (R<sup>2</sup> >0.99) was applied. The precision of injections was good (RSD = 3-11%, N=10) and the standards were reproducibly generated (RSD = 3.20%, N=3). A total number of 4 landfill sites and 5 sewage sludge treatment sites were sampled. One landfill site contained 15 different Sn-compounds, 5 species of which had a concentration of more than 13 ng/l, with a maximum concentration of 1050 ng/l for Me<sub>4</sub>Sn. Overall, the concentration range of most of the Sn-compounds was 0,01-0,5 ng/l and some unknown species could also be identified. In addition, the permethylated species of As, Se, Sb and Bi could be detected in the range of 0,01 – 117 ng/l. Although their concentration was usually relatively low (at 0,01 – 0,09 ng/l), the variety of volatile Sn-compounds in the sludge fermentation gas samples was quite astonishing. Me<sub>3</sub>Bi and Me<sub>3</sub>Sb were the dominant species in the sludge fermentation gases at concentrations of up to 42 ng/l.
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Clutterbuck, Amberlie A. "Method Development for the Collection and Instrumental Analysis of Harmful Compounds in Mainstream Hookah Smoke." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1491227953201259.
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Kim, Alexander Walter. "Construction and validation of a GC-ICP-MS instrument for the analysis of organometals and other trace element species." Thesis, University of Plymouth, 1993. http://hdl.handle.net/10026.1/1676.
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Vike, Kristine. "Oil spill forensics : Identification of sources for oil spills by using data generated by GC-MS and ICP-MS combined with multivariate statistics and the COSIWeb database." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for kjemi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-24920.
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This work has been a preliminary study, aimed at investigating whether or not trace metal Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) analysis could be a viable tool in the oil spill investigation toolbox, after having been abandoned over 20 years ago. The sample material was two previous oil spills, Full City and Server, and various heavily weathered oil samples gathered from islands off the Trøndelag coast. The islands were Kya, Sula, Vesterkalven, Storkalven, Kunna, and the bay Kjervågsundet on the larger island Frøya. The samples were prepared in a laboratory and analysed by Gas Chromatography-Flame Ionization Detector (GC-FID), Gas Chromatography-Mass Spectrometry-Selective Ion Monitoring (GC-MS-SIM) and ICP-MS. Through integration of key elements in the oil, also known as biomarkers, by an online database called COSIWeb, the weathered samples were classified as “crude oil”, “non-NS (North Sea) crude oil”, “bunker oil”, “unknown” and “not oil”. This classification was used as a guide to assess the viability of the trace metal analysis done by ICP-MS. The database also provided correlation calculations and five of the weathered bunker oil samples were linked to oils outside the database by “probable match”. Principal Component Analysis (PCA) was used to investigate the ability each dataset had to classify the different weathered oil types and oil spill samples Full City and Server. Subsequently, Partial Least Squares-Regression (PLS-R) was used to investigate the stability and robustness of both datasets from GC-MS-SIM and ICP-MS together, before Partial Least Squares-Discriminant Analysis (PLS-DA) was applied to investigate if the clusters seen in PCA were significant. By PLS-DA two subgroups of crude oils were identified, possibly related to terrestrial or marine source material in the oil. Of the 46 weathered samples found on various islands, 14 samples were classified as non-NS crude oils, 9 samples were classified as crude oils, 11 samples were classified as bunker oils, 7 samples were classified as unknown oil samples, and 5 samples were classified as not oil. The last group could be oil-like material such as plastic, rubber, coal or other organic material. The most important trace metal ratios identified in this study were ratios which have been previously been singled out as important in oil analysis. These were Ni/V, V/S, U/Pb and Mn/Fe. Other ratios were helpful as well, but these were the most influential ones. The Ni/V ratio was able to separate Full City samples from Server samples without any outliers or fuzzy classification.
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Nguyen, Thu-Hoai. "Abiotic methylation of inorganic mercury in natural waters : Method development for determination of monomethylmercury in natural waters by GC-ICP-MS." Thesis, Umeå universitet, Kemiska institutionen, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-150627.
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Grüter, Ulrike M. [Verfasser]. "Analyse von metall(oid)organischen Verbindungen in festen, flüssigen und gasförmigen Proben mittels (HG)/LT-GC/ICP-MS-Kopplung / Ulrike M Grüter." Aachen : Shaker, 2003. http://d-nb.info/1179025601/34.
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Aguerre, Sandrine. "Développement de méthodes analytiques associant la SPME à des techniques couplées GC-détecteur spécifique (FPD, PFPD, MIP-AES, ICP-AES, ICP-MS) pour la spéciation de l'étain et du sélénium." Pau, 2001. http://www.theses.fr/2001PAUU3038.
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La toxicité des métaux et métalloi͏̈des vis à vis des différentes parties de l'écosystème est fortement liée à leur forme physico-chimique. Aussi, la mise au point de méthodes de spéciation suffisamment sensibles pour assurer leur suivi systématique dans les milieux naturels est-elle indispensable. Ce travail présente en grande partie le développement de nouvelles méthodes analytiques pour la spéciation des composés organostanniques. Les innovations proposées reposent sur l'utilisation d'une technique de préconcentration, la SPME (ou microextraction sur phase solide) et sur le développement de couplages associant la chromatographie en phase gazeuse (GC) à divers détecteurs spécifiques (FPD, PFPD, MIP-AES, ICP-AES, ICP-MS). Les différents paramètres influençant les étapes de sorption et de désorption des butyl- et phénylétains en SPME ont été évalués et les conditions opératoires optimisées par le biais de la méthodologie des plans d'expériences. De nouvelles lignes de transfert entre la partie GC et l'ICP-MS / ICP-AES ont été testées et les performances des cinq détecteurs ont été comparées en terme de sensibilité et sélectivité. Toutes les méthodes permettent d'atteindre des limites de détection inférieures à 0. 5 ng(Sn). L-1 pour l'ensemble des composés étudiés, soit un gain de performances d'un facteur 100 à 700 par rapport à l'extraction liquide-liquide classiquement utilisée. L'analyse d'eaux, sédiments, tissus biologiques et boues de station d'épuration a permis d'évaluer les possibilités de ces méthodes dans le cas d'échantillons réels. Par ailleurs, une étude approfondie des phénomènes de sorption des organoétains en SPME a mis en évidence un comportement de désorption spontanée ainsi que l'influence importante des substances humiques sur leurs rendements d'extraction. Enfin, afin d'élargir les champs d'utilisation de la SPME, son potentiel en vue de la spéciation des formes volatiles et inorganiques du sélénium par GC-PFPD a été évalué<br>Toxicity of metals and metalloids towards the different parts of the ecosystem is highly dependent on their chemical form. Therefore, the development of sensitive speciation methods should be performed to allow their monitoring in the environment. A large part of this work deals with the development of new analytical procedures for the speciation of organotin compounds. The innovations are based on the use of a new preconcentration technique, SPME (solid phase microextraction) and on the hyphenation of gas chromatography (GC) with different specific detectors (FPD, PFPD, MIP-AES, ICP-AES, ICP-MS). Sorption and desorption steps in SPME have been studied and optimised using experimental design methodology. For the first time, new transfer lines (GC-ICP-MS and GC-ICP-AES) have been tested and the performances of all the detectors were compared in terms of selectivity and sensitivity. All the procedures allow detection limits lower then 0. 5 ng(Sn). L-1 to be reached for butyl- and phenyltins. Water samples, sediments, biological tissues and sludge from wastewater treatment plant have been analysed in order to evaluate the suitability of this method on real samples. A kinetic study of sorption-desorption behaviour of organotins during SPME has been performed. A spontaneous desorption behaviour has been noted. The influence of humic substances, representative of natural samples, on extraction yields has also been demonstrated. In a last part, potential of SPME for the sorption of methylated and inorganic forms of selenium followed by GC-PFPD analysis has been explored. First applications on water samples have been carried out
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Särnholm, Evelina. "Analyzing components of barrier coatings in different fractions during a repulping process." Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-93414.
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During paper manufacturing, coating and adhesives are added to paper and cardboard to improve quality and durability. When the paper is later recycled or becoming new paper, the coatings may pollute the water used in the recycling process. Thus, it is important to know in which fraction these coatings finish during the process. In this study, laboratory made samples that mimic the repulping and paper making process is used. The different fractions of the processes were analyzed for a clay as well as a polymer coating. Metal content from clay coating is analyzed using inductively coupled plasma-mass spectrometry and microwave plasma-atomic emission spectrometry. For analyzing polymer coating, gas chromatography-mass spectrometry was used. From the result of the analysis the Reject sample, which was collected with a bigger mesh sieve in a repulping system, contained the highest amount of both clay and polymer coating. The other sample fractions from the repulping process and paper making process, did not contain as high mass content of either clay nor polymer coating.
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Pietilä, H. (Heidi). "Development of analytical methods for ultra-trace determination of total mercury and methyl mercury in natural water and peat soil samples for environmental monitoring." Doctoral thesis, Oulun yliopisto, 2014. http://urn.fi/urn:isbn:9789526206202.
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Abstract Mercury is a global pollutant that accumulates easily in forest soils, even in remote areas. Mercury accumulated in soils can be subsequently released into surface waters causing an increased eco-toxicological and human health risk. The most toxic form of mercury to humans and wildlife is methyl mercury (MeHg), which can be formed in the environment via methylation processes. In freshwaters, MeHg is readily accumulated in fish, which are the main source of human exposure to MeHg. The determination of both total mercury and MeHg concentrations in environmental samples, such as natural waters and soils, is important in environmental risk assessment. This study involved the development of analytical methods for the determination of ultra-trace total mercury and MeHg concentrations in humic-rich natural water and peat soil samples. Each developed method was carefully optimized and validated by using real natural water and peat soil samples, certified reference materials and/or reference methods. The cold vapor inductively coupled plasma mass spectrometry (CV-ICP-MS) method developed during this study was found to be a reliable method for the determination of total ultra-trace mercury concentrations in natural freshwaters. Purge and trap gas chromatography, coupled to an ICP-MS, was used in mercury speciation analysis. Together with species-specific isotope dilution this technique proved to be a reliable method in MeHg determinations. Prior to instrumental determination, MeHg was successfully isolated from humic-rich water and peat soil samples using N2-assisted distillation. The analytical methods developed in this study were successfully applied to an investigation of the effects of forest harvesting practices on the mobilization of mercury in boreal forest catchments<br>Tiivistelmä Elohopeaa pääsee ilmakehään sekä luonnollisista lähteistä (mm. tulivuorenpurkaukset ja kiviaineksen rapautuminen), että ihmisen toiminnan kautta. Elohopean viipymäaika ilmakehässä on hyvin pitkä, minkä vuoksi se voi kulkeutua kauas päästölähteestä ennen päätymistään maaperään ja vesistöihin. Ympäristössä olevasta epäorgaanisesta elohopeasta voi muodostua erittäin myrkyllistä metyylielohopeaa, joka rikastuu helposti ravintoketjussa. Metyylielohopean muodostuminen on merkittävä osa elohopean biogeokemiallista kiertoa, minkä vuoksi metyylielohopean määrittäminen näytteen kokonaiselohopeapitoisuuden ohella antaa tärkeää tietoa elohopean käyttäytymisestä ympäristössä. Tutkimuksessa kehitettiin analyysimenetelmät, joilla määritettiin ultrapieniä kokonaiselohopea- ja metyylielohopeapitoisuuksia humuspitoisista luonnonvesistä ja turvemaanäytteistä. Tutkimuksessa käytetyt näytteet oli kerätty turvemaametsien valuma-alueilta Sotkamosta. Luonnonvesinäytteiden kokonaiselohopeapitoisuuksien määrityksessä käytettiin kylmähöyrymenetelmää (CV) yhdistettynä induktiiviplasma-massaspektrometriaan (ICP-MS). Vesi- ja turvenäytteiden metyylielohopeapitoisuuksien määrityksessä elohopeaspesiekset erotettiin kaasukromatografisesti (GC) ja määritettiin isotooppilaimennus-ICP-MS:lla. Ennen GC-ICP-MS -määritystä näytteet esikäsiteltiin typpiavusteisella tislausmenetelmällä ja esikonsentroitiin ’purge and trap’ -tekniikalla. CV-ICP-MS ja ’purge and trap’ GC-ICP-MS -menetelmät optimoitiin huolellisesti sekä laiteparametrien, että reagenssimäärien suhteen. Menetelmillä saatavien tulosten oikeellisuus varmistettiin vertailumateriaalien ja/tai vertailumenetelmien avulla. Kehitettyjä analyysimenetelmiä hyödynnettiin tutkimuksessa, jossa seurattiin metsähakkuiden mahdollisia vaikutuksia elohopean huuhtoutumiseen ja metyloitumiseen ojitetuilla turvemailla
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Kaschak, Elisabeth [Verfasser]. "Untersuchungen zur biotischen Bildung von Methylquecksilber aus anorganischem Quecksilber durch intestinale Sulfat-reduzierende Bakterien und die Bestimmung alkylierter Quecksilberverbindungen mittels GC-ICP-MS und Isotopenverdünnungsanalyse / Elisabeth Kaschak." Mainz : Universitätsbibliothek Mainz, 2013. http://d-nb.info/1035157489/34.
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Da, fonseca Clemens Stéphanie. "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)." Phd thesis, AgroParisTech, 2011. http://pastel.archives-ouvertes.fr/pastel-00753697.
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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.
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Inumula, Vamshi. "Characterization and quantitative determination of aromatics, nitrogen, sulfur and trace metals in fuel and hydrocarbon samples." Youngstown State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1377188620.
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Carvalho, Luiz Souza. "Concentrações de metais e hidrocarbonetos policíclicos aromáticos associados ao material particulado atmosférico e fluxo de deposição seca em Salvador, Bahia." reponame:Repositório Institucional da UFBA, 2008. http://www.repositorio.ufba.br/ri/handle/ri/11136.
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Previous issue date: 2008<br>CAPES<br>Os metais traço e os hidrocarbonetos policíclicos aromáticos particulados transportados por via aérea são considerados como um risco á saúde e ao ambiente, pois podem ser absorvido pelo tecido do pulmão humano durante a respiração. A queima de combustível fóssil e da madeira, assim como a incineração de dejetos e processos industriais, são as principais fontes antrópicas de metais e hidrocarbonetos policíclicos aromáticos (PAH) á atmosfera.. Este trabalho tem a finalidade de determinar as concentrações em suspensão (TSP e PM10 de metais, assim como as concentrações e os perfis dos 16 PAH prioritários para estudos ambientais segundo a U.S. EPA), que estão agregados ao material particulado. Os metais: Fe, Mn, Cu e Zn determinados por ICP-OES, e os PAH foram separados por cromatografia gasosa, identificados e quantificados por GC-MS. A amostragem foi feita em três sítios em Salvador-BA: i) Estação de ônibus da Lapa, ii) Porto de Aratu, iii) Vila de Bananeira,,na ilha de Maré próximo ao Porto de Aratu. Os dados experimentais foram analisados usando o programa (STATISTICA 6 Stat Soft). Para os metais: Fe apresentou as concentrações mais elevadas (variou de 26,8 a 328µgm-3) na maioria dos sítios, exceto bananeiras, onde o Zn predominou (variou de 1,83 a 145µgm-3). Para os hidrocarbonetos policíclicos aromáticos: BbF apresentou maiores concentrações na maioria dos sítios (variou de 0,130 a 6850ng m-3), exceto na estação da Lapa, predominou CRY(variou de 0,075 a 6,85µgm-3). Os metais e PAH, são principalmente de fonte antrópica, e podem originar sérios problemas de saúde<br>Salvador
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Tukur, Aminu. "Antimony and acetaldehyde migration from Nigerian and British PET bottles into water and soft drinks under typical use conditions : concentration of migrants and some trace elements in polyethylene terephthalate and in bottled contents." Thesis, University of Bradford, 2011. http://hdl.handle.net/10454/5369.
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Also aged bottles are safer to use than new bottles because their chemical leaching was found to be lower than that of new bottles. This study recommends the reassessment of the absence of international guidelines for acetaldehyde in water and foods. The study also recommends that the amount of acetaldehyde that can be added to soft drinks as flavouring agent should be below the specific migration limit (SML) for migration of acetaldehyde from PET bottle into bottle contents. This is essential since the SML was designed to ensure that exposure to acetaldehyde, as a result of intake of bottled water and soft drinks in PET bottles, is below the tolerable daily intake (TDI) for acetaldehyde. As antimony was reported to go beyond the safe limits in some Nigerian bottled water and soft drinks after 11 months of storage this study discourages the use of bottle contents stored for a very long time.
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Callagy, Sandra. "An investigation into changes to trace metals and metabolic profiling in the diabetic retina." Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/an-investigation-into-changes-to-trace-metals-and-metabolic-profiling-in-the-diabetic-retina(213607b0-2a34-490a-bb17-2e08435eb446).html.
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Diabetes mellitus currently affects over 422 million people globally and over 80% of patients with diabetes will develop diabetic retinopathy. Patients with diabetic retinopathy initially develop background retinopathy, which does not cause significant deterioration of visual function; however, background retinopathy may progress and lead to proliferative diabetic retinopathy and diabetic macular oedema, both of which cause severe visual dysfunction if left untreated. Current therapies for diabetic retinopathy include invasive intravitreal injections and laser photocoagulation; however these treatments only attenuate the progression of proliferative diabetic retinopathy and diabetic macular oedema. Aside from prevention by maintaining good blood glucose and blood pressure control, there are currently no treatments to prevent progression to late-stage diabetic retinopathy and new innovations in the field have not significantly progressed. For this reason, we have used untargeted âomics approaches to identify previously unknown pathological pathways in diabetes. In this thesis, I have analysed a range of trace metals in donor retinas and found that total copper was increased in diabetic retinas compared with non-diabetic. This result was replicated in streptozotocin-induced diabetic rat retinas and further evidenced by upregulation of metallothioneins and caeruloplasmin in diabetic rat retinas compared with non-diabetic. Treatment with the copper chelator triethylenetetramine modulated these changes, the downstream effects of which require further study. This is the first description, to our knowledge, of dysregulated copper homeostasis in the diabetic retina. I have also mapped metabolic changes in streptozotocin-induced diabetic rat retinas and found previously undescribed metabolite changes such as diabetes-induced downregulation of scyllo inositol. This coincided with substantial changes to retinal lipids during diabetes and changes to individual lipids were consistent within their respective class. I have also found a pattern whereby regardless of the extent of change to a lipid class in diabetes, lipids containing docosahexaenoic acid (22:6 carbon chain) were consistently downregulated. This is thought to be the first study to describe this range of metabolite changes in the diabetic retina but also the first study to describe this range of metabolite analysis concomitantly within the same tissue sample. The data from this study provides new insights into metallomic and metabolic dysfunction in diabetic retinopathy and shown that these data are reproducible. We suggest that there is plenty of scope for further research to investigate mechanisms behind copper dysregulation, how this affects pathogenesis of diabetic retinopathy along with new insights into dysregulated metabolic pathways.
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Qvarnström, Johanna. "On the reliability of methods for the speciation of mercury based on chromatographic separation coupled to atomic spectrometric detection." Doctoral thesis, Umeå universitet, Kemi, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-111.
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This thesis deals with the reliability of methods for the speciation of mercury in environmental and biological samples. Problems with speciation methods that couple chromatography to atomic spectrometric detection and how to overcome the problems are discussed. Analytical techniques primarily studied and evaluated are high performance liquid chromatography-cold vapour-atomic absorption spectrometry (HPLC-CV-AAS), HPLC-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS), capillary electrophoresis-ICP-MS (CE-ICP-MS) and gas chromatography-ICP-MS (GC-ICP-MS). Applying a multi-capillary approach increased the analyte amount injected into a CE-ICP-MS system and improved the overall sensitivity. A microconcentric nebulizer with a cyclone spray chamber was shown to improve the detection limits for mercury species 3-13 times in HPLC-ICP-MS and 11-19 times in CE-ICP-MS compared to a cross-flow nebulizer with a Scott spray chamber. To decrease the interference of water vapour in HPLC-CV-AAS a Nafion dryer tube was inserted between the CV-generation and the detector. Methyl mercury was however lost in the Nafion unless it was reduced to elemental mercury prior transport through the dryer tube. During sample pre-treatment, incomplete extraction, losses and transformation (alkylation, dealkylation, oxidation and reduction) of mercury species can lead to significant errors (underestimation and overestimation) in the determination of the concentrations. Methods to detect and determine the degree of transformation as well as correct for errors caused by transformation are presented in the thesis. The preferable method use species-specific enriched stable isotope standards in combination with MS detection and a matrix based calculation scheme. This approach is very powerful as both the concentrations of the species as well as the degrees of transformation can be determined within each individual sample.
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Unger, Maria. "Identification of brominated organic compounds in aquatic biota and exploration of bromine isotope analysis for source apportionment." Doctoral thesis, Stockholms universitet, Institutionen för material- och miljökemi (MMK), 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-38871.
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Brominated organic compounds (BOCs) of both natural and anthropogenic origin are abundant in the environment. Most compounds are either clearly natural or clearly anthropogenic but some are of either mixed or uncertain origin. This thesis aims to identify some naturally produced BOCs and to develop a method for analysis of the bromine isotopic composition in BOCs found in the environment. Polybrominated dibenzo-p-dioxins (PBDDs) in the Baltic Sea are believed to be of natural origin although their source is unknown. Since marine sponges are major producers of brominated natural products in tropical waters, BOCs were quantified in a sponge (Ephydatia fluviatilis) from the Baltic Sea (Paper I). The results showed that the sponge does not seem to be a major producer of PBDDs in the Baltic Sea. In this study, mixed brominated/chlorinated dibenzo-p-dioxins were however discovered for the first time in a background environment without an apparent anthropogenic source. The use of nuclear magnetic resonance spectroscopy (NMR) is unusual in analytical environmental chemistry due to its sample requirements. Preparative capillary gas chromatography was used to isolate a sufficient amount of an unidentified BOC from northern bottlenose whale (Hyperoodon ampullatus) blubber (Paper II) to enable NMR analysis for identification of the compound. The bromine isotopic composition of BOCs may give information on the origin and environmental fate of these compounds. The first steps in this process are the development of a method to determine the bromine isotope ratio in environmentally relevant BOCs (Paper III) and measuring the bromine isotope ratio of several standard substances to establish an anthropogenic endpoint (Paper IV).<br>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.
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Lambertsson, Lars. "Mercury species transformations in marine and biological systems studied by isotope dilution mass spectrometry and stable isotope tracers." Doctoral thesis, Umeå : Univ, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-467.
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Gajdušek, Martin. "Bioflavouring piv pomocí studeného chmelení za použití českých chmelů." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2021. http://www.nusl.cz/ntk/nusl-449727.
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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.
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Totoe, Harriet. "Speciation of selenoamino acids and selenium compounds by GC-AED and HPLC-ICP-MS." 2004. https://scholarworks.umass.edu/dissertations/AAI3152753.
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The increasing demands for speciation in nutrition, clinical chemistry and toxicology have made the sole determination of the total element in a sample unsatisfactory. It is important to determine the chemical form (species) of the element; most often its oxidation state or its organometallic or complexed nature, since different species of the same element can range from harmless to essential to toxic. In order to address this challenge, a separation technique (gas chromatography, GC) that usually focuses on qualitative analysis was effectively interfaced with an element specific detection technique, atomic emission spectrometry (AED). Likewise liquid chromatography (HPLC) was interfaced to inductively coupled plasma mass spectrometry (ICP-MS) for the characterization of selenium compounds. The consumption of selenium nutritional supplements has been reported to provide anticarcinogenic benefits that are selenium compound dependent. The separation and identification of these selenium species is important in order to understand their activity and metabolism. In this study, methods were developed for the characterization of selenium species in selenized yeast, breath and urine samples. Enzymatic digestion of selenized-yeast samples followed by ethylchloroformate derivatization was used to dissolve amino acids and convert them to volatile compounds suitable for subsequent GC analysis. Volatile selenium species exhaled in breath were trapped on Tenax, then revolatilized by heating and sampled by solid phase microextraction. Gas chromatography with atomic emission detection (GC-AED) or gas chromatography with mass spectrometry (GC-MS) was employed for their detection. Selenium species in urine were characterized by ion-pair chromatography with ICP-MS detection. The monitoring of chromatographic eluents with element specific atomic spectroscopy detectors enabled the determination of selenium species in the enzymatic digests of selenized yeast, breath and urine samples. The analysis of archived selenized yeast samples by GC-AED and GC-MS revealed the presence of a previously unknown aminoacid, S-(methylseleno)cysteine. Low molecular weight organoselenium and mixed organosulfur-organoselenium compounds were identified by GC-AED in exhaled human breath samples from volunteers taking selenium nutritional supplements. Trimethylselenonium ion was identified in the urine of these volunteers by HPLC-ICP-MS.
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Demuth, Natascha [Verfasser]. "Massenspektrometrische Isotopenverdünnungsanalyse (MSIVA) als Validierungsmethode für Bestimmungen von Methylquecksilber mittels GC-ICP-MS / Natascha Demuth." 2001. http://d-nb.info/963161067/34.
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Saraiva, Marina Amaral. "Quantificação de metais pesados e de musks sintéticos em produtos alimentares." Master's thesis, 2014. http://hdl.handle.net/10362/13894.
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O presente trabalho surgiu com dois objectivos principais: avaliar o grau de contaminação, por metais pesados, em produtos hortícolas de duas zonas diferenciadas e avaliar as diferenças de concentrações de musks em diferentes amostras biológicas.
Numa primeira fase, perante os resultados obtidos para os metais pesados nas duas zonas diferenciadas (Vila Nova de Mil Fontes e Carrasqueira) foi possível avaliar o risco de exposição das duas populações.
Os produtos hortícolas utilizados no estudo do grau de contaminação foram: alfaces, couves, batatas e tomates. Numa tentativa de identificar uma possível fonte de contaminação foi analisado igualmente a água utilizada para rega e o solo que rodeava a cultura. O método usado na determinação foi a espectrometria de massa acoplada a plasma induzido (ICP-MS). Foram analisados os seguintes elementos: Manganês, Arsénio, Cádmio, Cobalto, Cobre, Chumbo, Estrôncio, Níquel, Crómio, Selénio e Zinco. Houve grandes variações das concentrações dos elementos entre as duas zonas em que os hortícolas, água e solo foram colhidos. Em todas as amostras, os elementos maioritários foram o zinco, o manganês e o estrôncio. Nas culturas, o chumbo era o elementos que apresentava concentrações mais baixas. Para a água utilizada nas regas, a zona da Carrasqueira apresenta concentrações muito baixas comparando com a zona de Vila Nova de Mil Fontes. Todos os valores encontrados nas culturas, na água e no solo se encontram abaixo dos valores máximos legislados.
A análise de risco, revela situações de alerta, para um individuo da Carraqueira e quatro individuos de Vila Nova de Mil Fontes, uma vez que para o arsénio a dose diária tolerável segundo a EFSA é de 0,30 μg/kg/dia e os valores encontrados foram 0,30; 0,33; 0,61; 0,42 e 0,34 μg/kg/dia, respectivamente.
A determinação de musks em amostras biológicas, como ostras e mexilhões, salmão (músculo, fígado e gónadas) e enguias de vidro, por cromatografia gasosa acoplada a espectrometria de massa (GC/MS) recorrendo ao metódo de QuEChERS revelou que o galaxolide e o tonalide foram os analitos maioritários em todas as amostras. De entre as amostras de ostras e mexilhões, as colhidas na ria de aveiro apresentam concentrações muito superiores para o galaxolide e o tonalide, 13,4 e 2,1 ng/g respectivamente, que as outras analisadas. Nas análises de salmão foram tidas em conta duas zonas diferenciadas, Nivelle e Bidassoa. Perante os resultados, a zona de bidassoa apresentou menor contaminação de musks nas amostras recolhidas. Por último as análises às enguias de vidro dopadas permitiu traçar a cinética de acumulação de galaxolide e tonalide por parte do organismo e por outro lado identificar o galaxolidone, metabolito resultante do galaxolide.
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Kresimon, Jutta [Verfasser]. "Untersuchung humaner Körperflüssigkeiten und Ausscheidungsprodukte auf metall- und metalloidorganische Verbindungen mittels HG/LT-GC/ICP-MS / von Jutta Kresimon." 2002. http://d-nb.info/968638465/34.
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Diaz-Bone, Roland Arturo [Verfasser]. "Untersuchung metall(oid)organischer Verbindungen nach biologischer Abfallbehandlung mittels einer neu entwickelten GC-ICP-MS-Methode / von Roland Arturo Diaz-Bone." 2006. http://d-nb.info/98253566X/34.
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