Dissertations / Theses: 'Solid-phase micro-extraction'

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Lang, Susann-Cathrin. "Bioavailability of HOCs in marine sediments : application of solid phase micro-extraction." Thesis, University of the West of Scotland, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.731775.

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CEYLAN, OZCAN. "ELECTROCHEMICALLY-AIDED CONTROL OF SOLID PHASE MICRO-EXTRACTION (EASPME) USING CONDUCTING POLYMER COATED FIBER." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1069853643.

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Ahmadi, Svensson Mozhgan. "Sampling and Analysis of Tars by Means of Photo Ionization Detection and Solid Phase Micro Extraction." Doctoral thesis, KTH, Kemisk apparatteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-131115.

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Gasification of biomass will likely play an important role in the production of energy and chemicals in a future sustainable society. However, during gasification impurities, such as tars, will be formed. Tars may cause fouling and blockages of equipment downstream the gasifier. It is therefore important to minimize the formation of tars, alternatively to remove the formed tars. These processes need to be monitored, which makes it necessary to develop tar analysis methods suitable for this task. This work describes the development of two tar analysis methods, an on-line method based on a photoionization detector (PID) and an off-line method based on solid phase microextraction (SPME). Both methods were successfully validated against the established solid phase adsorption (SPA) method. The method based on PID was shown to have a very fast response time. Furthermore, the PID method is selective towards tar, but only limited information will be obtained regarding the composition of the tar compounds. The PID method is suitable for applications where it is important to detect fast changes of the tar concentration, i.e. process monitoring. The SPME method was shown to be a very sensitive method for qualitative and quantitative tar analysis. The sampling temperature was shown to be crucial for obtaining analysis results with the wanted detection limit. The SPME method is suitable for applications where extremely low detection and quantification limits are needed, i.e. for syngas production.

QC 20131009

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Silva, Ana Claudia Lemes da. "Tipificação de meis brasileiros por micro-extração em fase solida combinada com cromatografia gasosa (SPME-CG)." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250209.

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Orientador: Fabio Augusto
Tese (doitorado) - Universidade Estadual de Campinas, Instituto de Quimica
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Resumo: O mel é uma das misturas mais complexas de carboidratos produzida pela natureza. É um alimento energético muito importante pelas suas propriedades nutritivas, pelo seu aroma e sabor que dependem fortemente das plantas, flores e condições climáticas presentes na região geográfica onde está localizada a colméia. Não existem metodologias que possibilitem identificação não subjetiva, rápida e confiável da origem floral do mel. O objetivo deste trabalho foi desenvolver uma metodologia que permitisse a identificação da origem floral de méis brasileiros a partir da caracterização química de sua fração de voláteis utilizando micro-extração em fase sólida através do headspace e cromatografia gasosa (HS-SPME-CG). Para o desenvolvimento da metodologia, foram avaliadas 90 amostras de méis brasileiros de vinte origens florais diferentes e variadas procedências geográficas. Onze destas amostras eram unitárias e permitiram apenas um estudo exploratório. Cada tipo de mel apresentou um perfil cromatográfico diferente. Foram identificados potenciais marcadores para os méis de eucalipto (Eucalyptus sp), laranja (Citrus sp), assa-peixe (Vernonia polianthes), cambará (Lantana montevidensis), morrão de candeia (Croton sp) e marmeleiro (Cydonia vulgaris). Os resultados obtidos mostraram que SPME-CG é útil na tipificação de méis e pode eventualmente ser utilizada na sua certificação
Abstract: Honey is one of the most complex mixtures of carbohydrates produced by Nature. It is a very important energetic food for its nutritional properties and for its aroma and flavor that depend strongly on the fauna, flowers and on the climatic conditions in the geographic region where the beehive is located. There are no objective, fast and reliable methodologies for the identification of the floral source of honeys. The objective of this work was to develop a methodology to allow identification of the floral source of Brazilian honeys through characterization of its volatile fraction using headspace solid phase microextraction and gas chromatography (HS-SPME-GC). To develop the methodology, 90 samples of Brazilian honeys of twenty different botanical sources and several geographic locations were employed. Eleven honey types had just one sample, allowing only exploratory studies. Different chromatographic profiles were obtained for honeys from different floral sources. Potential chemical markers were identified for the honeys of eucaliptus (Eucalyptus sp), orange (Citrus sp), assa-peixe (Vernonia polianthes), lantana (Lantana montevidensis), morrão of candeia (Croton sp) and quince (Cydonia vulgaris). The results obtained showed that SPME-GC is useful to identify the floral origin of honey and may eventually be used for its certification
Tese (doitorado) - Universidad
Quimica Analitica
Doutor em Ciências

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Schebywolok, Tomi. "Application of Relative Response Factors in Solid-Phase Micro Extraction GC/MS for the Determination of Polycyclic Aromatic Hydrocarbons in Water." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/37860.

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Solid-phase microextraction (SPME) coupled with gas chromatography/mass spectrometry (GC/MS) is routinely used to analyze polycyclic aromatic hydrocarbons (PAHs) in water. A common SPME-GC/MS approach quantifies target analytes using isotopically labeled standards (IISs); one IIS is needed for each target analyte. This approach is challenging, even prohibitive since IISs are often expensive; moreover, they are generally not available for each analyte of interest. This study developed a novel SPME-GC/MS approach for the quantification of PAHs in water. The new method, which employs only a small number of IISs, uses relative response factor (RRF) (i.e., analyte corresponding to IIS) to quantify PAHs in water. Possible matrix dependency of RRFs values was examined using water that was modified concerning different physical-chemical characteristics (i.e., ionic strength, pH, suspended solids, humic acid, and biological organic carbon represented by hemoglobin). The results revealed that RRFs are not noticeably affected by changing ionic strength and pH; the other three parameters did affect the RRFs. However, the results also showed that the effect is minimal when the solution is dilute (i.e., low concentrations of suspended solids, humic acid or hemoglobin). Relatively stable RRFs for dilute water solutions indicates that this approach can be used for routine quantification of water that does not contain prohibitive amounts of suspended solids, humic acid, and biological organic matter. The developed method was employed to quantify trace levels of PAHs in three different types of water, namely river water, well water, and bottled water. PAH levels in every kind of water were less than 100 ng/L level (i.e., 0.1 ppb). Analyses of spiked water samples containing 2 ng PAHs revealed correlations between calculated RRFs and the physical-chemical properties of the PAHs investigated (i.e., vapor pressure, boiling point, octanol/water partition coefficient, octanol/air partition coefficient, GC retention time). This implies that RRFs for PAHs not examined in this study can be predicted. Overall, the results presented herein constitute a meaningful contribution to the development of SPME-GC/MS methods for quantitative analysis of PAHs and other chemicals in dilute aqueous solutions. Moreover, the development of methods that alleviate the need for IISs corresponding to each target analyte.

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Andersson, Johan. "Odour Communication in Pieris Butterflies." Doctoral thesis, KTH, Chemistry, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3699.

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Jajuli, Maizatul Najwa. "Extraction liquid-liquide modulée électrochimiquement et microextraction en phase solide de composés pharmaceutiques sélectionnés." Electronic Thesis or Diss., Université de Lorraine, 2019. http://www.theses.fr/2019LORR0127.

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Les méthodes classiques de préparation d'échantillons pour la détermination de composés polaires, telles que l'extraction liquide-liquide (LLE) et l'extraction en phase solide (SPE), ne sont généralement pas efficaces en raison de multiples étapes, d’une faible récupération et d’une consommation élevée de solvants organiques. Cette thèse traite du développement de nouvelles méthodes de préparation d’échantillons, à savoir l’extraction par voie liquide-liquide modulée électrochimiquement (EMLLE) et l’extraction bar-micro en phase solide (bar-μ-SPE) afin de déterminer les composés pharmaceutiques metformine (MET), buformine (BUF), phénformine (PHEN) et propranolol (PROP). Dans la méthode EMLLE, un champ électrique a été appliqué pour extraire les composés pharmaceutiques ionisés à travers l’interface entre deux solutions électrolytiques non miscibles (ITIES). Des ITIES se forment lorsque deux solvants en vrac en phase aqueuse (chlorure de lithium) et en phase organique (I, 2-dichloroéthane), contenant l’électrolyte, sont mis en contact. Le potentiel de transfert pour chaque analyte a été analysé par voltamétrie. Le potentiel de transfert varie avec leur lipophilie; propranolol
Conventional sample preparation methods for the determination of polar compounds such as liquid-liquid extraction (LLE) and solid phase extraction (SPE) are generally not effective because of their multiple steps, low recovery and high consumption of organic solvents. Thus, this thesis deals with the development of new sample preparation methods, i.e, electrochemically modulated liquid-liquid extraction (EMLLE) and bar-micro solid phase extraction (bar-μ-SPE) to determine selected pharmaceutical compounds, i.e., metformin (MET), buformin (BUF), phenformin (PHEN), and propranolol (PROP) having varied lipophilicity in biological samples. In the EMLLE method, the aid of electric field was utilized to extract the pharmaceutical compounds across the interface between two immiscible electrolyte solutions (ITIES). ITIES formed when two bulk solvents aqueous phase (lithium chloride) and organic phase (I,2-dichloroethane), both containing electrolytes are brought into contact. Transfer potential for each analyte was analysed by voltammetry. The trend of transfer potential followed their lipophilicity; propranolol < phenformin < phenyl biguanide < metformin. Extraction of the analytes was performed by applying fixed potential to the biphasic system using potentiostat for 15 mins. The extraction performance was poor. Design of another ITIES cell and imposing interfacial potential by chemical polarization was done to enhance the extraction performance of this method. Thus, the EMLLE technique based on application of interfacial potential due to the presence of different concentrations of tetramethylammonium ion (TMA+) as common ion in each phase was studied. The optimum extraction conditions for this method are, [TMA+]o = 10 mM, [TMA+]w = 0.001 mM, Vorg = 2 mL, pHsample = 9, rotation speed = 900 rpm, extraction time = 600 s. The optimised parameters for back-extraction are: [TMA+]back = 50 mM, Vfinal = 0.1 mL, pHback = 2 . Nearly 100 % extraction of targeted analytes was achieved, and the enrichment factor obtained was up to ~ 60 for biguanide compounds. In the bar-μ -SPE method, adsorbent and a tiny metal rod was placed in a polypropylene membrane bag. Among the various adsorbents studied, graphene and zeolite showed some potential. Thus, extraction conditions were optimised for each adsorbent and adsorbent mixture. Despite the optimisations, the extraction was low (5.03-39.2 %). Nevertheless, enrichment factors of 1.49 -14.9 were obtained. Both proposed methods were applied to the determination of the analytes in urine. On the whole, the newly proposed methods are simple and markedly reduced consumption of organic solvents

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Huertas-Rivera, Adhly M. "Identification of the Active Odors From Illicit Substances for the Development of Optimal Canine Training Aids." FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/2990.

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The exploitation of illicit substances, such as drugs and explosives, is on the rise. Special attention must therefore be considered to reduce the transportation and storage of these illicit substances by improving the capability of detection, even when hidden from view. Although analytical methods of detection for both drugs and explosives have improved over time, biological detectors, such as canines, are still commonly used. In comparison to humans, these canines have a larger number of olfactory receptors and a greater olfactory epithelium surface area, providing them with a more enhanced olfaction than that of humans. The premise for the detection of illicit drugs and explosives is based on the premise that these substances though hidden, will emit volatile organic compounds (VOCs). These VOCs are not often the parent drug or explosive, they are essentially a chemical associated with the source and provide a reliable indication of the illicit substance. Previous successful research has been conducted on the identification of the active odors present in the headspace of cocaine, methamphetamine, and MDMA but instead for marijuana and heroin there have been minimum success. Thus, in the present research a method using headspace solid-phase microextraction coupled to gas chromatography-mass spectrometry (HS-SPME-GC-MS) was optimized to identify the VOCs makeup of heroin and marijuana to further identify the active odor compound(s) responsible for the alert response of biological detectors (canines). A mixture of acetic acid and acetylsalicylic acid was identified as target odor mimic for heroin by certified detector canines, while a mixture of limonene and caryophyllene was recognized as odor mimic for marijuana by conducting ORTs. The training aids developed successfully mimic the scent of the actual illicit substance and can be used to improve the capabilities of both drug and explosive detection canines. Additionally, as growing threat of improvised explosives has created a worldwide concern and emphasized the requirement of a greater spectra of canine training aids that covers the complete range of explosives available, a new approach for the creation of training aids for IEDs have been evaluated. The use of a dynamic collection system have proved to be an option to develop fast and reliable canine training aids for IEDs.

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Rohanifar, Ahmad. "Conductive Polymers for Electrochemical Analysis and Extraction." University of Toledo / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1544809010837595.

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Ribeiro, Aline Larissa Campos Fernandes. "Estudo de aromas de algumas espécies frutíferas Amazônicas pela técnica de HS-SMPE-GC-MS." Universidade Federal do Amazonas, 2015. http://tede.ufam.edu.br/handle/tede/5676.

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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The need to identify the volatile composition of food is growing every year, mainly driven by the industry. The volatile compounds present in food is very important because they are responsible for their characteristic aroma, which in turn contributes to the taste and consequently to the attraction for the food. The attractive taste of tropical fruits is increasing the consumption of these fruits worldwide, and hence the aroma and flavor of these fruits are getting attention of the industry. Considering this growing interest and the fact that the aroma of most amazonian fruits have not yet been studied, the aim of this study was the characterization of the aroma of three Amazon edible fruits consumed in Manaus region: banana pacovan (Musa paradisiaca L), cajarana (Spondias dulcis Park) and cubiu (Solanum sessiliflorum Dunal). The volatile compounds were extracted by Headspace Solid Phase Microextraction technique and the components were separated and identified by high resolution gas chromatography coupled to mass spectrometry. Two types of commercial SPME fibers were used, CAR-PDMS and PDMS, to compare their efficiency. The extraction capability for each fiber has varied, PDMS fiber was able to extract more components for banana and cubiu, whereas CAR-PDMS for cajarana. Alcohols, aldehydes and esthers were identified in all three fruits, and esthers were more present in cubiu. Terpenes were identified solely in cajarana and carboxylic acids were present only in banana pacova aroma.
A necessidade do conhecimento da composição dos voláteis em alimentos vem crescendo a cada ano, principalmente impulsionada pela indústria. As substâncias voláteis presentes em um alimento são importantes, pois são elas que conferem o seu aroma característico, que por sua vez contribui para o sabor e consequentemente pela atração pelo alimento. O sabor atrativo das frutas tropicais está estimulando o consumo destas frutas em todo o mundo e, devido a isso, o aroma e sabor destes frutos vêm chamando a atenção das indústrias, demonstrando o interesse na caracterização de cada uma delas. Tendo em vista esse grande interesse e o fato do aroma da maioria dos frutos exóticos amazônicos não terem sido estudados ainda, este trabalho teve como objetivo a caracterização do aroma de três frutos comestíveis adquiridos na região de Manaus: banana pacovan (Musa paradisiaca L), cajarana (Spondias dulcis Park) e cubiu (Solanum sessiliflorum Dunal). Os componentes voláteis foram extraídos utilizando a técnica de microextração em fase sólida por “headspace” e a identificação foi realizada através de análises por cromatografia gasosa de alta resolução acoplada com espectrometria de massas. Para a extração dos voláteis, dois tipos de recobrimento de fibra foram utilizados, CAR-PDMS e PDMS, que são normalmente utilizadas nas análises de voláteis. Os resultados obtidos para análise dos aromas de todos os frutos estudados mostraram que a quantidade de substâncias extraídas variou entre as fibras. Os resultados para a banana e para o cubiu apresentaram maior quantidade de componentes extraídos com a fibra PDMS, enquanto para a cajarana foi obtido com a fibra CAR-PDMS. Nos três frutos foram identificadas substâncias voláteis pertencentes à classe de álcoois, aldeídos e ésteres, que foi a principal classe encontrada em todas as análises, principalmente no cubiu. Terpenos foram identificados apenas no aroma da cajarana e ácidos carboxílicos apenas no aroma da banana pacovan.

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Koch, David R. "Field and laboratory application of a gas chromatograph low thermal mass resistively heated column system in detecting traditional and non-traditional chemical warfare agents using solid phase micro-extraction /." Download the thesis in PDF, 2005. http://www.lrc.usuhs.mil/dissertations/pdf/Koch2005.pdf.

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Song, Shin Miin, and shinmiin@singnet com sg. "Comprehensive two-dimensional gas chromatography (GCxGC ) for drug analysis." RMIT University. Applied Sciences, 2006. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080627.114511.

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Separation technologies have occupied a central role in the current practices of analytical methods used for drug analysis today. As the emphasis in contemporary drug analysis shifts towards ultra-trace concentrations, the contribution from unwanted matrix interferences takes on greater significance. In order to single out a trace substance with confidence from a rapidly expanding list of drug compounds (and their metabolites) in real complex specimens, analytical technologies must evolve to keep up with such trends. Today, the task of unambiguous identification in forensic toxicology still relies heavily upon chromatographic methods based on mass spectrometric detection, in particular GC-MS in electron ionisation (EI) mode. Although the combined informing power of (EI) GC-MS has served faithfully in a myriad of drug application studies to date, we may ask if (EI) GC-MS will remain competitive in meeting the impending needs of ultra-trace drug analysis in the fut ure? To what extent of reliability can sample clean-up strategies be used in ultra-trace analysis without risking the loss of important analytes of interest? The increasing use of tandem mass spectrometry with one-dimensional (1D) chromatographic techniques (e.g. GC-MS/MS) at its simplest, considers that single-column chromatographic analysis with mass spectrometry alone is not sufficient in providing unambiguous confirmation of the identity of any given peak, particularly when there are peak-overlap. Where the mass spectra of the individual overlapping peaks are highly similar, confounding interpretation of their identities may arise. By introducing an additional resolution element in the chromatographic domain of a 1D chromatographic system, the informing power of the analytical system can also be effectively raised by the boost in resolving power from two chromatographic elements. Thus this thesis sets out to address the analytical challenges of modern drug analysis through the application of high resolut ion comprehensive two-dimensional gas chromatography (GCeGC) to a series of representative drug studies of relevance to forensic sciences.

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Sartoratto, Adilson. "Desenvolvimentos metodologicos em microextração em fase solida acoplada a cromatografias gasosa e liquida." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250204.

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Orientador: Fabio Augusto
Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica
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Resumo: O trabalho que teve como objetivo desenvolver metodologias em Microextração em Fase Sólida para utilização em cromatografia líquida e gasosa será apresentado em dois capítulos: no primeiro capítulo a análise de pesticidas organofosforados (OPP) em amostras aquosas e infusão de plantas foi realizada por cromatografia líquida de alta eficiência/detetor de arranjo de diodos (HPLC-DAD) utilizando uma interface de dessorção para SPME e uma fibra sol-gel Carbowax 20M ormosil, produzidas em nosso laboratório. Após avaliação de desempenho da interface e eficiência da fibra sol-gel, uma metodologia de análise foi desenvolvida, avaliando-se os principais parâmetros de validação: sensibilidade, linearidade, faixa linear, exatidão, precisão, limites de detecção e quantificação. No segundo capítulo, tentamos relacionar a composição química de voláteis de plantas analisados por SPME-GC-MS com a atividade antimicrobiana de óleos essenciais. A avaliação dos voláteis foi feita utilizando-se dois tipos de fibras comerciais: PDMS e PDMS/DVB e também pela análise do óleo essencial obtido por métodos tradicionais. A atividade antimicrobiana dos óleos essenciais foi realizada pelo método da concentração mínima inibitória (MIC) com a finalidade de selecionar óleos com potencial terapêutico, em substituição às drogas existentes no mercado.
Abstract: The present work is presented in two chapters that had the scope of developing methodologies for solid phase microextraction coupled to gas and liquid chromatography. The first chapter discusses analysis of organophosphorous pesticides in water soluble samples and plant infusions by High Performance Liquid Chromatography coupled to photodiode array detector (HPLC-DAD) using a SPME desorption interface and Carbowax 20M sol-gel fiber, both produced in lab. After interface and sol-gel fiber efficiency evaluation an analysis method was developed that considered validation parameters: sensibility, linearity, linear range, accuracy, precision, detection limit, and quantification limit. In the second chapter we proposed to establish a relationship among plant's chemical volatile composition analyzed by SPME-GC-MS and antimicrobial activity of essential oils. Two commercial fibers: PDMS and PDMS-DVB were employed for essential oil analysis. Essential oils with potential therapeutic properties in substitution to known commercial drugs were chosen by minimum inhibition concentration experimental model.
Doutorado
Quimica Analitica
Doutor em Ciências

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Alves, Claudete. "\"Análise de fármacos em fluidos biológicos empregando o acoplamento SPME-LC/MS\"." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/75/75132/tde-18042007-171857/.

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Os métodos convencionais para a determinação de fármacos em fluidos biológicos baseiam-se em técnicas cromatográficas e imunoquímicas. O tratamento prévio de amostras biológicas, o qual abrange as etapas de extração, pré-concentração e clean-up, tem sido requerido nas análises de fármacos, para aumentar a sensibilidade e seletividade analítica. No entanto, nos últimos anos, com o avanço das técnicas instrumentais, diversas técnicas têm sido avaliados para a análise de diferentes fármacos em fluidos biológicos, destacando-se entre elas a Microextração em Fase Sólida (SPME) e a Cromatografia Líquida acoplada a Espectrometria de Massas (LC/MS). A SPME apresenta uma série de vantagens em relação às técnicas de extração tradicionais, ou seja: não requer instrumentação analítica sofisticada, não utiliza solvente orgânico, permite automação das análises, a reutilização das fibras extratoras e integra em um único sistema, a extração, concentração e introdução da amostra no sistema cromatográfico. Neste trabalho, foi desenvolvida uma interface versátil e de baixo custo, que permite o acoplamento das técnicas SPME-LC/MS para análise dos fármacos antidepressivos tricíclicos e anticonvulsivantes. O planejamento fatorial empregado mostrou ser uma ferramenta estatística importante e simples, sendo obtido mais informações com um número menor de experimentos, avaliando não só os efeitos principais como os efeitos de interação de todas as variáveis nas respostas. As condições cromatográficas otimizadas foram adequadas para a análise por LC/MS. Os níveis de detecção alcançados ressaltam a importância e destaque da técnica de cromatografia líquida de alta eficiência acoplada à espectrometria de massas (LC/MS). O método desenvolvido, tanto para os fármacos antidepressivos tricíclicos como para os anticonvulsivantes, mostrou especificidade, precisão, linearidade e limite de quantificação adequado para a análise.
Conventional methods used for the determination of drugs in biological fluids are based on chromatographic and immunochemical techniques. The biological samples treatment - which includes extraction, pre-concentration and clean up steps has been required in drugs analysis in order to increase both analytical sensitivity and selectivity. Nevertheless, lately, within the advancements in instrumentation, different techniques have been evaluated for the analysis of different drugs in biological fluids, such as: solid phase microextraction (SPME) and liquid chromatography coupled to mass spectrometry (LC/MS). SPME presents many advantages towards the conventional extraction techniques (soxhlet, LLE and SPE), which include: use of simple analytical instrumentation, analysis automation, reuse of extractor fibers and integration of extraction, concentration and sample introduction in the same chromatographic system. In this work, a versatile and low cost interface was developed, which allows the coupling of SPME-LC/MS techniques to tricyclic antidepressants and anticonvulsivant drugs analysis. The employed factorial design has shown to be a simple and useful statistical tool. With this device more information could be obtained with fewer experiments by evaluating not only the main interaction effects but also the interaction effects of all variables on the results. The optimized chromatographic conditions were adequate for LC/MS analysis. The obtained detection levels highlight the importance of high performance liquid chromatography coupled to mass spectrometry (LC/MS). The developed method, for both tricyclic antidepressants and anticonvulsivants drugs, has presented specificity, accuracy, linearity and adequate limit of detection for this analysis.

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Beiner, Kerstin. "Untersuchungen zur selektiven Anreicherung organischer Schwefelverbindungen aus wäßrigen Proben." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2002. http://nbn-resolving.de/urn:nbn:de:swb:14-1014974713093-57112.

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Die Aufgabenstellung der vorliegenden Arbeit ergab sich aus der Notwendigkeit organische Schwefelverbindungen in stark belasteten wäßrigen Proben zu identifizieren, um das toxische Potential dieser Wässer abschätzen zu können. Bei der chromatographischen Trennung und Identifizierung der einzelnen Komponenten traten insbesondere dann Probleme auf, wenn die einzelnen Komponenten in Konzentrationsbereichen auftraten die um Größenordnungen differierten. Da auch durch selektive Detektion unbekannte Komponenten nicht direkt identifiziert werden können, wurde angestrebt durch geeignete Probenvorbereitungsschritte einerseits die gesuchten Zielsubstanzen anzureichern und andererseits störende Matrixbestandteile abzutrennen. Ziel der vorliegenden Arbeit war es effektive und möglichst selektive Verfahren zu entwickeln, um organische Schwefelverbindungen aus wäßrigen Proben anzureichern. Im Rahmen dieser Arbeit wurden zwei Möglichkeiten erarbeitet. Für die Anreicherung von leicht- bis mittelflüchtigen Substanzen erwies sich die Adsorption an Ag2S aus der Gasphase als geeignet. Zur Extraktion mittel- bis schwerflüchtiger Verbindungen wurde eine Festphasenextraktionstechnik an einem mit Blei(II)ionen modifizierten Kationenaustauschermaterial entwickelt. Ein Vergleich beider Techniken erfolgte mit dem Verfahren der Festphasenmikroextraktion (SPME). Die adsorptive Anreicherung an Ag2S wurde mit einem Membranextraktionsschritt (ME) , Thermodesorption (TD) und GC/MS gekoppelt. Wie die SPME kann sie für den Nachweis leicht- bis mittelflüchtiger Verbindungen aus flüssigen, festen und gasförmigen Proben eingesetzt werden. Gegenüber der Festphasenmikroextraktion ermöglicht sie den Einsatz größerer Probemengen, was in niedrigeren Nachweisgrenzen (oberer bis mittlerer ng/l-Bereich) resultiert. Nachteile der entwickelten Technik bilden der höhere experimentelle Aufwand und die längeren Analysenzeiten. Das Festphasenextraktionsverfahren an dem mit Pb(II)ionen beladenen Kationenaustauschermaterial erlaubt gegenüber der SPME ebenfalls die Anwendung größerer Probenmengen und höherer Konzentrationen. Beide Verfahren zeigen vergleichbare Nachweisgrenzen (unterer µg/l - bis oberer ng/l-Bereich) für die verwendeten Modellsubstanzen. Sowohl durch die adsorptive Anreicherung an Silbersulfid als auch durch die Festphasenextraktion an Pb(II)-modifizierten Ionenaustauschmaterialien wird die Identifizierung unbekannter organischer Schwefelverbindungen in stark belasteten Proben erheblich erleichtert. Beide Methoden bilden als einfache und leistungsfähige Techniken wirkungsvolle Ergänzungen zu bereits etablierten Anreicherungsverfahren. Neben der Identifizierung und Analyse können die Techniken ebenfalls zur Entfernung von schwefelhaltigen Substanzen aus verschiedenen Matrizes dienen. Anwendungsmöglichkeiten der entwickelten Methoden bestehen neben der Umweltanalytik auch in der Lebensmittelchemie.

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Sinkevičius, Robertas. "Prieskoninių augalų, eterinių aliejų sudėties tyrimas, panaudojant skirtingus ekstrakcijos metodus." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2012. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2012~D_20120620_124200-02369.

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Augant pasaulinei pramonei aplinkos tarša nepaliaujamai didėja, tad augalai augantys užterštoje aplinkoje, savo sudėtyje taip pat turi nemažai įvairių junginių, kurie gali įtakoti juos vartojančių žmonių sveikatą. Eterinių aliejų išgautų iš augalų tyrimas yra vienas iš būdų nustatant augalo kokybę, užtikrinant, kad taršalai nepateks tolesniam perdirbimui. Eteriniams aliejams išgauti yra daug būdų, kaip kad distiliacija vandens garais, šviežių aromatinių dalių išspaudimas, ekstrakcija tirpikliais, tačiau tokie išgavos būdai būdingesni išgaunant didelius kiekius, tad reikia ir daug žaliavos. Tyrimams naudojami greitesni, bei mažiau žaliavos reikalaujantys metodai, kaip, kad ekstrakcija superkritiniais skysčiais, kietafazė mikroekstrakcija bei ekstrakcija iš bandinio viršerdvės. Šio darbo tikslas - eterinių aliejų, išgautų superkritinių skysčių ekstrakcijos, kietafazės mikroekstrakcijos bei tiesioginės viršerdvės ekstrakcijos būdais, sudėties nustatymas dujų chromatografijos – masių spektroskopijos metodu. Panaudojant gautus duomenis nustatyti kuris ekstrakcijos būdas pasižymi didžiausiu efektyvumu. Duomenų tikslumo užtikrinimui bandiniai pakartotinai leisti po 3 kartus, identifikuoti junginiai tikrinti skaičiuojant kovačo retencijos indeksus ir juos lyginant su jau žinomais indeksais internetinėje bibliotekoje. Darbo metu remiantis gautais duomenimis nustatyta efektyviausias eterinių aliejų ekstrakcijos metodas, junginiai, esantys bandiniuose bei būdingųjų junginių kiekis.
As the word industry develops, the amount of wastes, that are being released in to our environment is always increasing, as a result vegetables that are growing in such a environment are also contaminated with compounds that can affect the health of people that are using them. Many methods can be used to obtain essential oils, such as distillation using water vapour, extruding from fresh fragrant, extraction using solvents, but these kind of methods are used for getting large amounts of essential oils, so staple is used. For chemical analysis faster and less staple demanding methods are used, such as, super critical fluid extraction, solid phase micro extraction or direct head space extraction. The goal of this work is to determine the composition of essential oils and to estimate witch, super critical fluid extraction, solid phase micro extraction or direct head space extraction is the best for obtaining essential oils from spice herbs. In order to secure the precision of data each sample was analyzed three times, for correct compound identification kovach retention indexes were calculated and compared with the known ones on the internet library. Using the obtained data the most effective method foe essential oils obtaining was determined, also compound composition in samples and the amount of specific compounds were analyzed.

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17

Beiner, Kerstin. "Untersuchungen zur selektiven Anreicherung organischer Schwefelverbindungen aus wäßrigen Proben." Doctoral thesis, Technische Universität Dresden, 2001. https://tud.qucosa.de/id/qucosa%3A24125.

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Die Aufgabenstellung der vorliegenden Arbeit ergab sich aus der Notwendigkeit organische Schwefelverbindungen in stark belasteten wäßrigen Proben zu identifizieren, um das toxische Potential dieser Wässer abschätzen zu können. Bei der chromatographischen Trennung und Identifizierung der einzelnen Komponenten traten insbesondere dann Probleme auf, wenn die einzelnen Komponenten in Konzentrationsbereichen auftraten die um Größenordnungen differierten. Da auch durch selektive Detektion unbekannte Komponenten nicht direkt identifiziert werden können, wurde angestrebt durch geeignete Probenvorbereitungsschritte einerseits die gesuchten Zielsubstanzen anzureichern und andererseits störende Matrixbestandteile abzutrennen. Ziel der vorliegenden Arbeit war es effektive und möglichst selektive Verfahren zu entwickeln, um organische Schwefelverbindungen aus wäßrigen Proben anzureichern. Im Rahmen dieser Arbeit wurden zwei Möglichkeiten erarbeitet. Für die Anreicherung von leicht- bis mittelflüchtigen Substanzen erwies sich die Adsorption an Ag2S aus der Gasphase als geeignet. Zur Extraktion mittel- bis schwerflüchtiger Verbindungen wurde eine Festphasenextraktionstechnik an einem mit Blei(II)ionen modifizierten Kationenaustauschermaterial entwickelt. Ein Vergleich beider Techniken erfolgte mit dem Verfahren der Festphasenmikroextraktion (SPME). Die adsorptive Anreicherung an Ag2S wurde mit einem Membranextraktionsschritt (ME) , Thermodesorption (TD) und GC/MS gekoppelt. Wie die SPME kann sie für den Nachweis leicht- bis mittelflüchtiger Verbindungen aus flüssigen, festen und gasförmigen Proben eingesetzt werden. Gegenüber der Festphasenmikroextraktion ermöglicht sie den Einsatz größerer Probemengen, was in niedrigeren Nachweisgrenzen (oberer bis mittlerer ng/l-Bereich) resultiert. Nachteile der entwickelten Technik bilden der höhere experimentelle Aufwand und die längeren Analysenzeiten. Das Festphasenextraktionsverfahren an dem mit Pb(II)ionen beladenen Kationenaustauschermaterial erlaubt gegenüber der SPME ebenfalls die Anwendung größerer Probenmengen und höherer Konzentrationen. Beide Verfahren zeigen vergleichbare Nachweisgrenzen (unterer µg/l - bis oberer ng/l-Bereich) für die verwendeten Modellsubstanzen. Sowohl durch die adsorptive Anreicherung an Silbersulfid als auch durch die Festphasenextraktion an Pb(II)-modifizierten Ionenaustauschmaterialien wird die Identifizierung unbekannter organischer Schwefelverbindungen in stark belasteten Proben erheblich erleichtert. Beide Methoden bilden als einfache und leistungsfähige Techniken wirkungsvolle Ergänzungen zu bereits etablierten Anreicherungsverfahren. Neben der Identifizierung und Analyse können die Techniken ebenfalls zur Entfernung von schwefelhaltigen Substanzen aus verschiedenen Matrizes dienen. Anwendungsmöglichkeiten der entwickelten Methoden bestehen neben der Umweltanalytik auch in der Lebensmittelchemie.

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18

Li, Dan. "Identification and Differentiation of Tier 1 Bacterial Agents Using Gas Chromatography-Mass Spectrometry." BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/4053.

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A simple method was developed for detection and differentiation of five Tier 1 bacterial agents, including Bacillus anthracis, Francisella tularensis, Yersinia pestis, Burkholderia pseudomallei and Burkholderia mallei as well as their closely related near neighbors by gas chromatography-mass spectrometry (GC-MS). Generally, different classes of compounds can be used as biomarkers for biowarfare agent detection, including nucleic acids (i.e., DNA or RNA), proteins (i.e., antibodies), carbohydrates (i.e., sugars), lipopolysaccharides, lipids (i.e., fatty acids) and small molecules. One-step thermochemolysis (TCM) was developed to provide GC-MS detectable biomarker signatures, including sugars, fatty acids and small molecules. Solid phase micro-extraction (SPME) was used for biomarker extraction, concentration and introduction into the GC-MS. Statistical algorithms were constructed using a combination of biomarkers for the five agents, which were robust against different growth conditions (medium and temperature). A general GC-MS temperature program was developed for all five Tier 1 bacteria. The total analysis time, including TCM, SPME extraction and GC-MS, is approximately 40 min. The total-ion chromatograms are very different for the five species. The final goal of this research was to develop an accurate, fast, simple, robust and automated method for field application. Therefore, an automated sample preparation system was designed, constructed and tested. The system automatically controls the movement of sample vials from one position to another, crimping of septum caps onto the vials, precise delivery of reagents and TCM reaction times and temperatures. The specific operations of introduction of sample vials, SPME sampling, injection into the GC-MS system and ejection of used vials from the system were performed manually in this study, although they can be integrated into the automated system. Manual SPME sampling is performed by following visual and audible signal prompts for inserting the fiber into and retracting it from the sampling port. A rotating carousel design allows for simultaneous sample collection, reaction, biomarker extraction and analysis of sequential samples. Bacillus species were used to test this autoreactor, and 96% of the samples were correctly identified using a statistical algorithm. This research applies not only to the rapid identification of Tier 1 agents after a biological attack, but should also benefit clinical diagnosis, which is essential to effective treatment.

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Truong, Tai Van. "Differentiation of Bacillus Endospores from Gas Chromatography-Mass Spectrometry of Biomarkers Produced by Thermochemolysis Methylation." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2726.

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Methods for fast, simple detection of biomarkers to detect and differentiate closely related Bacillus endospores including Bacillus anthracis (BA), Bacillus thuringiensis (BT), Bacillus atrophaeus (BG), and Bacillus cereus (BC) using thermochemolysis and methylation (TCM), coiled wire filament (CWF), solid phase micro extraction (SPME) and gas chromatography-mass spectrometry (GC-MS) were developed. The main biomarkers detected and used for differentiation include dipicolinic acid methyl ester (DPAME), fatty acid methyl esters (FAMEs), 3-methyl-2-butenoic acid methyl ester (3M2BAME), 2-butenoic acid methyl ester (2BAME), and several methylated sugars. TCM of endospores was performed based on hydrolysis and methylation at elevated temperature after the endospores were mixed with sulfuric acid (H2SO4) with or without addition of tetramethylammonium hydroxide (TMAH) in methanol (MeOH). TCM products were then introduced into a heated GC injector port using a coiled wire filament (CWF) or solid phase microextraction (SPME) for detection and differentiation of the endospores by GC-MS.The CWF, which consisted of a tiny platinum helical wire coil attached to a retractable plunger that moved the coil in and out of a syringe needle housing, allowed for sampling to be accomplished by dipping the CWF in an endospore sample suspension, evaporating the suspension liquid, and then introducing the CWF into the injection port to enable on-line TCM. New SPME techniques, including half-half extraction, coated-needle extraction (CNE), and a new home-made polymer coated needle were used to speed up solid phase micro extraction of biomarkers produced from TCM. These simplified the detection of anthrose and other biomarkers. TCM with a CWF and TCM with SPME produced high intensity profiles of DPAME, FAMEs, 2BAME, 3M2BAME and methylated sugars. While the presence of DPAME can be used for the general detection of endospores (Bacillus and Clostridium) and the presence of 3M2BAME for the detection of BA, specific saturated and unsaturated C15, C16, and C17 fatty acid methyl esters and methylated sugars provide additional information for differentiating various Bacillus species grown at different temperatures and in different media. DPAME was detected in samples containing as few as 2,500 and 6,000 endospores using TCM-CWF with and without a concentration step, respectively. GC-MS peak area percent reproducibility for FAMEs using TCM and CWF varied from 3 to 13% (RSD). Better than 97% correct predictability of Bacillus species identity was obtained from a blind experiment consisting of 145 samples using DPAME and specific FAMEs. Conventional SPME and a modified form of "in-needle" extraction allow for detection of the biomarkers in less than 35 min. The detection limits with SPME sample introduction injection were approximately 5 x 103 endospores.Using these approaches, differentiation of Bacillus endospores and other biological agents grown under different conditions were based on the following characteristics: (1) presence of DPAME and specific FAMEs (iso or anteiso C15:0 and iso or anteiso C17:0) in Bacillus endospores, (2) unique presence of 3M2BAME (anthrose by-product) in BA, (3) absence of 2-butenoic acid methyl ester in BG, and (4) presence and absence of specific methylated monosaccharides in various Bacillus species. Clostridium endospores and non-sporulating bacteria, such as Yersinia pestis (YP) and Francisella tularensis (FT) could also be easily distinguished from Bacillus endospores based on the presence and absence of several specific sugar derivatives and fatty acid methyl esters (FAMEs), such as iso or anteiso C15:0 and iso or anteiso C17:0, and > C18 FAMEs which were simultaneously produced during TCM.

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Colόn, Crespo Lauren J. "Determination of Human Scent Biomarkers for Race, Ethnicity and Gender." FIU Digital Commons, 2016. http://digitalcommons.fiu.edu/etd/2442.

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Human scent has been the focal point of diverse scientific interests and research initiatives for the past several years. The knowledge gained about its composition has favored the advancement of multiple disciplines, and promoted the development of a wide variety of applications. Among these applications is the use of human scent as a resource for Forensic investigations, where scent profiles are often used as evidence to associate individuals to the scene of a crime. The characteristic nature of individual human scent has enabled this type of evidence to be used as a biometric tool for the differentiation of subjects. Nevertheless, the present study discusses a new perspective towards human scent's role and application in Forensic investigations. The foundation of this new perspective consists of employing human scent’s biometric quality to classify individuals using common traits. In this research study, underarm and hand odor samples were collected from Caucasian, Hispanic and East Asian individuals, of both genders. Subjects were also organized into 3 different age groups: 18-30, 35-50 and 55+ years. Headspace Solid Phase Micro-extraction Gas Chromatography Mass Spectrometry (HS-SPME-GC-MS) was used to create individual scent profiles for the evaluation of subject classification by age, gender and race/ethnicity. Individual classification was assessed through the identification of qualitative and quantitative patterns in the volatile organic compound (VOC) constituents that characterize human scent. Principal Component and Linear Discriminant analyses of the collected scent profiles, led to the identification and validation of characteristic VOC marker combinations for age, gender and race/ethnicity. Statistical analysis facilitated group classification and differentiation on the basis of these traits. Moreover, this study also evaluated the use of solvent extraction as a complementary technique to HS-SPME for human scent analysis. Findings from this assessment revealed that the simultaneous consideration of data from both extraction techniques favors an enhancement of the classification of subjects by means of human scent. The discoveries achieved in this study represent a significant step for human scent as a forensic tool. The outcome of this research has cleared a new path for further human scent investigation, and highlighted its further relevance to forensic applications.

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21

Hussain, Noor Feuza. "Electrochemical Remedy and Analysis for the Environment Based on the New Polymer-DNA Composite Material." Digital Commons @ East Tennessee State University, 2005. https://dc.etsu.edu/etd/1047.

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In this work a new material, the conducting polymer-DNA composite, has been reported for the first time due to its promise in micro extraction, transfer, and release of cations under controlled potential conditions by using electrochemically assisted solid phase micro extraction (SPME). The Polypyrrole/DNA composite can be formed easily by oxidation of pyrrole monomers in the presence of chromosomal DNA by electropolymerization. Environmental significant pollutants such as Cd, Pb, Hg, Co, Zn, Cu, and Bi metal ions can be extracted from the aqueous solution and are able to be transferred to another medium defined as the release solution where the metals were detected by anodic stripping voltammetry. Using Cd2+ as a model, this method has been examined to optimize its operational condition. Extraction efficiency and potential interference for this method were studied.

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22

De, Perre Chloé. "Etude des interactions matière organique dissoute : contaminants organiques dans l'environnement aquatique." Thesis, Bordeaux 1, 2009. http://www.theses.fr/2009BOR13933/document.

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Suite à une anthropisation généralisée des ressources aquatiques et des écosystèmes associés, on retrouve de nombreux contaminants chimiques organiques à l’état de traces dans l’environnement aquatique. En parallèle de ces contaminants, dans les milieux aquatiques on retrouve également des molécules rassemblées sous la dénomination « matière organique dissoute (MOD) », qui sont des mélanges complexes de molécules et macromolécules, qui peuvent s’associer à ces contaminants et influencer leur comportement et leur distribution. Les interactions entre MOD et contaminants peuvent s’avérer difficiles à étudier étant donné qu’elles sont dépendantes de nombreux facteurs tels que la nature des contaminants et de la MOD, ainsi que des paramètres physico-chimiques du milieu. L’objectif de ces travaux était donc d’étudier ces interactions. Les contaminants organiques choisis ont été les Hydrocarbures Aromatiques Polycycliques (HAP) et les substances pharmaceutiques. D’autre part, plusieurs types de MOD d’origine naturelle ou commerciale ont été utilisés. Pour étudier les interactions, plusieurs techniques analytiques ont été développées dont la micro-extraction sur phase solide couplée à la chromatographie en phase gazeuse et à la spectrométrie de masse et l’extinction de fluorescence
In relation with a widespread human impact on aquatic resources and ecosystems, many organic chemical contaminants are present at trace levels in aquatic environments. In parallel to these contaminants, dissolved organic matter (DOM), which is composed of complex mixtures of molecules and macromolecules, is also found and could be associated with these contaminants and influence their behavior and distribution. Interactions between DOM and contaminants can be very difficult to understand because they depend on many factors such as the nature of contaminants and DOM, as well as on environmental physico-chemical parameters. The aim of this work was thus to study these interactions. Organic contaminants studied were Polycyclic Aromatic Hydrocarbons (PAHs) and pharmaceuticals. On the other hand, several types of natural and commercial DOM have been used. To study the interactions, several analytical techniques have been developed like solid phase microextraction coupled to gas chromatography and mass spectrometry and fluorescence quenching

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23

Sanchez, Claudia L. Ms. "Evaluation of the Scent Collection System for Its Effectiveness in Volatile Organic Compound Collection and Use in Canine Training." FIU Digital Commons, 2015. http://digitalcommons.fiu.edu/etd/1914.

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As a result of increased terrorist activity around the world, the development of a canine training aid suitable for daily military operations is necessary to provide effective canine explosive detection. Since the use of sniffer dogs has proven to be a reliable resource for the rapid detection of explosive volatiles organic compounds, the present study evaluated the ability of the Human Scent Collection System (HSCS) device for the creation of training aids for plasticized / tagged explosives, nitroglycerin and TNT containing explosives, and smokeless powders for canine training purposes. Through canine field testing, it was demonstrated that volatiles dynamically collected from real explosive material provided a positive canine response showing the effectiveness of the HSCS in creating canine training aids that can be used immediately or up to several weeks (3) after collection under proper storage conditions. These reliable non-hazardous training aids allow its use in areas where real explosive material aids are not practical and/or available.

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Brito-Berger, Ingrid. "Développement de méthodes d'extraction et d'analyse multi-résidus pour le suivi de contaminants organiques polyaromatiques et de métabolites oxygénés dans les sédiments." Thesis, Normandie, 2018. http://www.theses.fr/2018NORMR058/document.

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Dans ce travail, deux méthodes d'extraction multi-résidus de contaminants présents dans des sédiments ont été développées. Dans la première partie de cette étude, une méthode a été développée pour l’'extraction simultanée de deux familles de métabolites oxygénés d'hydrocarbures aromatiques polycycliques (HAP), les quinones et les HAP hydroxylés (OH-HAP). Une approche chimiométrique a permis de déterminer les paramètres influant sur l’extraction assistée par micro-ondes (MAE) et une zone de compromis a été trouvée pour extraire de manière optimale les deux familles de composés. Deux méthodologies d’analyses chromatographiques ont été développées et validées pour analyser les extraits, puis comparées, à savoir la chromatographie liquide haute performance couplée aux détections UV et fluorimétrique (HPLC-UV-Fluo) et la chromatographie en phase gazeuse couplée à un spectromètre de masse par impact électronique (CPG-SM). En CPG-SM, des réactions de silylation des OH-HAP et d’acétylation des quinones ont dû être mises au point, afin d’abaisser les limites de détection (LD), en particulier pour les ortho-quinones. En HPLC-UV-Fluo, les LD étaient plus faibles qu’en CPG-SM, surtout pour les OH-HAP détectés en Fluo et l'analyse était plus rapide, sans processus de dérivation; mais la détection n’étant pas sélective, l’identification des analytes s’est avérée hazardeuse. Le choix s’est donc porté sur la CPG-SM pour une analyse plus fiable des deux familles de composés de matrices sédimentaires naturellement contaminées. Dans la deuxième partie de ce travail de thèse, une nouvelle méthodologie d'extraction a été développée et validée, basée sur la dispersion en phase solide de la matrice solide (MSPD), capable d'extraire mais aussi de purifier l’échantillon, méthodologie par ailleurs simple et rapide. Deux familles de composés ont été extraits simultanément à partir de sédiments, les HAP et les polychlorobiphényles (PCB). Un certain nombre de paramètres ont été optimisés, tels la nature des agents dispersants, le temps de broyage, le volume et la nature du mélange de solvants d’élution. Dans un deuxième temps, l'introduction des OH-HAP dans le processus analytique a amené à coupler à la MSPD une autre méthode d’extraction/purification beaucoup plus sélective, basée sur les polymères à empreintes moléculaires (MIP). En effet, les interférents polaires, restés piégés par l’agent dispersant polaire dans la première cartouche contenant le sédiment broyé, devaient être élués afin de libérer les OH-HAP, qui a leur tour devaient être retenus sélectivement dans un MIP empreint pour les phénols, pour fournir une élution finale exempte d'autres composés. Il a été montré que ces MIPs pouvaient extraire sélectivement les OH-HAP de faible et de haut poids moléculaire, mais il fallait choisir soigneusement le solvant de percolation pour ne pas endommager le polymère. Cependant, la difficulté principale a été de désorber les OH-HAP fortement retenus par le sédiment par liaison hydrogène. Cela a pu être réalisé pour les OH-HAP légers, en utilisant un mélange de solvants avec un effet de relargage par un sel, mais pas pour les OH-HAP lourds, trop fortement adsorbés sur la matrice sédimentaire. Par ailleurs, il a fallu utiliser une grande quantité de polymère à empreinte moléculaire à cause de la compétition pour les sites de reconnaissance entre les OH-HAP et des composés phénoliques
In this work two multiresidual methods for extracting contaminants from sediments were developed. In the first part of this study, a method was developed for extracting simultaneously two groups of oxygenated metabolites of polycyclic aromatic hydrocarbons (PAHs), quinones and hydroxylated PAHs (hydroxy-PAHs). A chemometric approach allowed us to determine the influential parameters on microwave assisted extraction (MAE), and a compromise could be found for extracting quantitatively both families of compounds. Two chromatographic analytical methodologies were developed and validated for analysing the extracts: high performance liquid chromatography coupled with fluorimetric and ultraviolet detection (HPLC-UV-FLD) and gas chromatography coupled with an electronic impact mass spectrometer (GC-MS). Using GC-MS, reactions of silylation of hydroxy-PAHs and of acetylation of quinones had to be developed, to decrease detection limits (LOD), particularly for ortho-quinones. Using HPLC-UV-FLD, LODs were lower than using GC-MS, particularly for hydroxy-PAHs detected by FLD, and the analysis was faster, without derivatization; but the detectors were not selective, and identification of analytes was doubtful. Choice was done to favour GC-MS for a more reliable analysis of the two families of compounds extracted from naturally contaminated sediments. In the second part of this thesis work, a new fast and simple extraction methodology was developed and validated, based on matrix solid phase dispersion (MSPD), capable of extracting and purifying simultaneously sediment samples. Two families of compounds were simultaneously extracted from sediments, PAHs and polychlorobiphenyls (PCBs). Many parameters were optimized, as the nature of dispersing agents, the time of grinding, the volume and nature of elution solvent mixtures. In a second step, hydroxy-PAHs were introduced in the analytical process, which led us to add another more selective extraction/purification method to MSPD, based on molecularly imprinted polymers (MIPs). Indeed polar interfering compounds, trapped by the polar dispersant in the first cartridge containing the blended sediment, had to be eluted to release hydroxy-PAHs, which in turn had to be selectively retained by the polymer, imprinted for phenols, to provide a final eluate free from other polar compounds. It was demonstrated that those MIPs could selectively extract low and high molecular weight hydroxy-PAHs, but appropriate percolating solvents had to be chosen to avoid polymer damages. However, the main difficulty was to desorb hydroxy-PAHs strongly retained by the sediment matrix through hydrogen bonds. It could be achieved for light hydroxy-PAHs, using a mixture of eluting solvents with salting-out effect, but not for heavy hydroxy-PAHs which stayed strongly sorbed on the sediment matrix. Furthermore we needed to use high amounts of imprinted polymer because of the competition for recognition sites between hydroxy-PAHs and phenolic compounds

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Percio, Maycon Fernando. "Desenvolvimento de suportes vítreos e vitrocerâmicos baseados no sistema Li2O-BaO-SiO2 mofificados pelos óxidos Nb2O5, TiO2, V2O5 e ZrO2, para microextração em fase sólida (SPME-CG)." Universidade Estadual do Oeste do Paraná, 2012. http://tede.unioeste.br:8080/tede/handle/tede/1911.

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In the present work a vitreous composition based on combination of the oxides BaO-SiO2-Li2O modified by adding of oxides Nb2O5, TiO2, V2O5 and ZrO2 as nucleating agent was evaluated and used in the manufacture of glass and glass-ceramic fibers for use in SPME-CG. The stability of the resulting glasses was accompained by X-ray diffraction (XRD) and differential thermal analysis (DTA). The stability parameters of Weinberg (KW), Hubrÿ (KH), Lu e Liu (KLL), Du and Huang (KDU) and Saad and Poulain (KSP) were obtained by DTA data. By KSP was observed that stability of glassy phases follows the descending order: Composition 5 (ZrO2) > Composition 2 (Nb2O5) > Composition 1 (without nucleant) > Composition 4 (V2O5) > Composition 3 (TiO2). Through these data it was possible to determine the apparent activation energies of the crystallization process by the crystallization peaks of the DTA curves, whereby the decreasing order was obtained: Composition 5 (ZrO2)> Composition 4 (V2O5) > Composition 2 (Nb2O5) > Composition 3 (TiO2) > Composition 1 (without nucleant). It was found, through the Avrami index, a surface crystallization mechanism of the compositions that leads to a correspondent transition to the glass ceramic. From DRX data obtained after thermal treatment at varying time, the TTT diagrams (Time, Temperature and Transformation) of the compositions were constructed, which delimited the conditions for preparation of glass ceramic fibers. The XRD analysis indicated that the main crystalline phases formed after heat treatments are rhombic Li2SiO3 Li2Si2O5. The fibers obtained were further tested in chromatographic analysis by HS-SPME-GC of the methanol in aqueous solution at concentrations of 10 and 100 mgL-1 with satisfactory results.
No presente trabalho, foram estudadas composições vítreas baseada na combinação dos óxidos Li2O-BaO-SiO2 modificadas pelos óxidos Nb2O5, TiO2, V2O5 e ZrO2, utilizados como nucleantes na fabricação de fibras de vidro e vitrocerâmicas para a utilização em SPME-CG. Determinou-se a estabilidade vítrea para cada composição através da difração de raio-X (DRX) e análise térmica diferencial (DTA) sendo observada a estabilidade das fases vítreas na ordem decrescente: Composição 5 (ZrO2) > Composição 2 (Nb2O5) > Composição 1 (sem nucleante) > Composição 4 (V2O5) > Composição 3 (TiO2). Através destes dados foi possível determinar as energias de ativação aparente das fases cristalinas através dos picos de cristalização das curvas de DTA, cuja ordem decrescente obtida foi: Composição 5 (ZrO2) > Composição 4 (V2O5) > Composição 2 (Nb2O5) > Composição 3 (TiO2) > Composição 1 (sem nucleante). Verificou-se através do índice de Avrami que as composições vítreas obtidas apresentaram mecanismo de nucleação de superfície para a formação do vitrocerâmico. Os dados de DTA possibilitaram a obtenção de diagramas de Tempo, Temperatura e Transformação (TTT), que delimitaram as condições de preparo das fibras vitrocerâmicas. Foram fabricados 5 tipos diferentes de fibras vítreas (Fibras A), que após tratamento térmico deram origem a fibras vitrocêramicas parcialmente cristalizadas (Fibras B) e fibras vitrocerâmicas totalmente cristalizadas (Fibras C), resultando um total de 15 espécies de fibras de composições e estruturas cristalinas diferentes. As análises por DRX indicaram que as principais fases cristalinas formadas depois dos tratamentos térmicos são Li2SiO3 e Li2Si2O5 ortorrômbicos. As fibras obtidas foram ainda testadas em análises cromatográficas por Cromatografia Gasosa na extração de metanol em solução aquosa nas concentrações de 10 e 100 mgL-1 com resultados satisfatórios.

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26

Schallschmidt, Kristin. "Biomarker in Atemluft." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät, 2017. http://dx.doi.org/10.18452/17800.

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Ein nicht-invasiver Atemtest zur Lungenkrebsdetektion setzt Kenntnis über lungenkrebsspezifische Substanzen voraus. Die Identifizierung von Lungenkrebsbiomarkern in der Atemluft war das Ziel dieser Arbeit. Leichtflüchtige organische Substanzen (VOC) wurden als Zielkomponenten ausgewählt. Für die VOC-Analytik wurde eine SPME-GC-MS-Methode entwickelt und sowohl auf Modellsysteme als auch auf Realproben angewendet. Drei Lungenadenokarzinomzelllinien wurden in-vitro untersucht. Die VOC-Analyse wurde mit drei verschiedenen Probenahmestrategien durchgeführt und es war ein deutlicher Hintergrundeinfluss der eingesetzten Einwegzellkulturflaschen auf das analysierte VOC-Profil feststellbar. Trotzdem konnten signifikante Unterschiede zwischen Tumorzellen und zellfreien Nährmedien beobachtet werden: 1-Propanol wurde von den Zellen produziert, während der Gehalt einiger Aldehyde sank. Die eingeschränkte Ähnlichkeit des gewählten Zellkulturmodells mit realen Atemluftproben bedingt eine geringe Eignung dieser Ergebnisse für die Biomarkerableitung. Ein Gasmodell auf Basis angefeuchteter, synthetischer Luft wurde als Grundlage für die qualitätsgesicherte, quantitative VOC-Analyse der realen Atemluftproben konzipiert. Diese Modellluft wurde mit 24 Zielsubstanzen (Alkane, Aromaten, sauerstoffhaltige Spezies) sowie 3 Matrix-VOC mit starker Dominanz in den Atemluftproben (Isopren, Aceton, 2-Propanol) angereichert. In Kooperation mit zwei Berliner Kliniken wurden 37 Atemluftproben von Lungenkrebspatienten und 23 Proben von Gesunden gesammelt. Die Anwendung von 1-Butanol als univariater Marker erlaubt eine Erkennung von Lungenkrebs mit einer Sensitivität von 92% und Spezifität von 78%. Durch lineare Diskriminanzanalyse konnte ein Set aus 4 VOC (1-Butanol, 2-Butanon, 2-Pentanon, n-Hexanal) ermittelt werden, welches ebenfalls eine Sensitivität von 92% und mit 87% eine höhere Spezifität aufwies. Gegebenenfalls handelt es sich bei diesen Substanzen jedoch nur um allgemeine Krankheitsmarker.
A non-invasive breath test for lung cancer detection would be favorable but knowledge on lung cancer specific substances is required. This work aims at the identification of potential lung cancer biomarkers in breath. Volatile organic compounds (VOC) were chosen as targets and a SPME-GC-MS method was developed to analyze the VOC profiles of model systems and real samples. Three lung adenocarcinoma cell lines were investigated in-vitro. The VOC analysis, carried out with 3 different sampling strategies, was influenced by the VOC background of the used disposable culture vessels. Changes in the VOC profiles of cell lines compared to cell-free culture media were obvious: 1-propanol was released by the tumor cells whereas the content of some aldehydes was diminished. The similarity of this model system with real breath samples of lung cancer patients was seen to be insignificant. Consequently, these cell cultures were not suitable for biomarker identification. A gaseous model consisting of humidified synthetic air was developed. It was fortified with 24 target VOC (alkanes, aromatics and oxygenated species) as well as 3 matrix compounds (isoprene, acetone and 2-propanol) dominating patients’ VOC profiles in breath. This model was used for the quality assured quantitative VOC analysis in real breath samples. In cooperation with two hospitals 37 single mixed expiratory breath samples from lung cancer patients and 23 from healthy controls were collected. Applying 1-butanol as an univariate biomarker patients and controls were discriminated with a sensitivity of 92% and a specificity of 78%. Linear discriminant analysis displayed a set of 4 VOC (1-butanol, 2-butanone, 2-pentanone, n-hexanal) with similar sensitivity but higher specificity of 87%. However, these potential biomarkers might rather be a consequence of illness in general.

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27

Bradford, Brock. "Application of Solid Phase Micro-Extraction (SPME) - GC-MS for Identifying Pyrolysis Compounds in Textiles." 2016. http://hdl.handle.net/1993/31833.

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This thesis project describes research using headspace solid phase micro-extraction with gas chromatography (HS-SPME GC-MS) as an analytical tool for assessing textile fibres. It was found that this method required a temperature of >500oC to pyrolize the textile sample. A total of 5 minutes was determined to be the optimal time for collecting the volatile analytes. Numerous analytes were found to be chemical markers for each of the individual textile fibres. The chemical markers are qualitatively used to describe each textile uniquely, and it was found that by using the chromatographic patterns, the textiles could be identified individually and in mixtures containing two textiles. Lastly, by accelerating the age of the textile fibres by means of heat, ultra-violet light, and humidity, a comparison was made between the un-aged and aged fibres. It was found that each of the techniques arose different results and in some cases new compounds.
October 2016

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28

Chung, Wu-Hsun, and 鍾武勳. "Dispersive micro solid-phase extraction for the rapid determination of selected emerging contaminants – method optimization and applications." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/62pa54.

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博士
國立中央大學
化學學系
104
The general developed microextraction methods were time-consuming, higher cost, eco-unfriendly, and carryover problems. A dispersive micro solid-phase extraction (DmSPE) coupled solvent/thermal desorption techinque was able to improve these disadvantages, and the parameters were optimized by experimental design, which was proposed by this thesis. This thesis was divided into three parts: the first part developed and validated an optimized method for the determination of seven synthetic target musks in water samples. The method involves a DmSPE plus ultrasound-assisted solvent desorption (UASD) prior to their determination by gas chromatography-mass spectrometry (GC-MS). Factors affecting the extraction efficiency of the target analytes from water samples and UASD were optimized by a Box-Behnken design (BBD) method. The optimal extraction conditions involved immersing 10.1 mg of a octadecyl (C18) bonded silica adsorbent in a 50 mL water sample. After 10.4 min of extraction by vigorously shaking, the adsorbent was collected and dried on a filter, and the target musks were desorbed by ultrasound for 38 sec with n-hexane (200 μL) as the desorption solvent. A preliminary analysis of the effluents from municipal wastewater treatment plants (MWTP) and river water samples revealed that galaxolide (HHCB) and tonalide (AHTN) were the two most commonly detected synthetic musks; their concentration were determined to range from 88 to 690 ng/L for effluent samples, and 5 to 320 ng/L for river water samples. In the second part, a simple, rapid, and solvent-free method involves the use of DmSPE coupled with direct thermal desorption (TD) -GC-MS for the analysis of ﬁve target musks in water samples. The parameters affecting the extraction efﬁciency of the target analytes from water sample and the thermal desorption conditions in the GC injection-port were optimized using a central composite design (CCD) method. The optimal extraction conditions involved immersing 3.2 mg of a C18 adsorbent in a 10 mL water sample. After extraction by vigorously shaking for 1.0 min, the adsorbents were collected and dried on a ﬁlter. The adsorbents were transferred to a micro-vial, which was directly inserted into GC temperature programmed injector, and the extracted target analytes were then thermally desorbed in the GC injection port at 337 °C for 3.8 min. Using a standard addition method, a preliminary analysis of the river water samples revealed that the concentrations of HHCB and AHTN were determined to in the range from 11 to 140 ng/L. Finally, a solvent-free method involves the use of DmSPE followed by the simultaneous silylation and thermal desorption (SSTD) -GC-MS for the rapid analysis of six benzophenone-type UV absorbers in water samples. A Plackett-Burman design was used for screening and a CCD for optimizing the major factors was applied. The optimal experimental conditions involved immersing 1.5 mg of the Oasis HLB adsorbent in a 10 mL portion of water sample. After vigorous shaking for 1 min, the adsorbents were transferred to a micro-vial, and were dried at 122 °C for 3.5 min, after cooling, 2 μL of the BSTFA silylating reagent was added. For SSTD, the injection-port temperature was held at 70 °C for 2.5 min for derivatization, and the temperature was then rapidly increased to 340 °C to allow the thermal desorption of the TMS-derivatives into the GC for 5.7 min. Using a standard addition method, a preliminary analysis of the MWTP efﬂuent and river water samples revealed that 2-hydroxy-4-methoxybenzophenone (BP-3) was the most common benzophenone-type UV absorber present. The concentrations of BP-3 ranged from 5.1 to 39.7 ng/L. The preliminary results of this dissertation reveals that these methods can satisfy analytical validation criteria, allow precise measurement of the trace levels of emerging contaminants in aqueous samples, and they are simple, low cost, effective, and eco-friendly method. In the future, these methods also can be further studied to apply in other fields, e.g., food, beverage, pharmaceutical, cosmetic, etc.

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Fu, Ssu-chieh, and 傅思潔. "Determination of NDMA in Aqueous samples by using dispersive Micro Solid Phase Extraction coupled with gas chromatography/mass spectrometry." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/28012794863993225796.

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碩士
國立中央大學
化學研究所
99
Abstract Disinfection has successfully applied to eliminate pathogens in various water supplies, however its byproducts (DBPs) cause unintended health risks to human. N-nitrosodimethylamine (NDMA) is one of the most toxic DBPs that raises the cancer risk. Due to its high toxicity, nowadays, the presence of NDMA and other N-nitrosamines in water is an emerging issue since many of them are suspected to be human carcinogens. They are also listed in the Unregulated Contaminant Monitoring Rule 2 (UCMR-2) by US-EPA. In this study, a simple sample pretreatment technique, dispersive micro-solid phase extraction (dMSPE), was developed for the extraction of NDMA and other N-nitrosamines (NAs) from aqueous samples. The parameters affecting the extraction efficiency were systematically investigated and the conditions optimized. The best extraction conditions involved the immersed 75 mg of carbon molecular sieve, carboxen 1003 (as adsorbent), in a 50 mL water sample containing 5% of sodium chloride in a sample tube. After 20 min of shaking extraction, the adsorbent was collected under rapidly filtered, and 150 ?L of dichloromethane was used to elute NAs from the adsorbent. The extract 10 ?L was then directly determined by large-volume injection gas chromatography with chemical ionization mass spectrometry (GC-CI/MS) under selected ion storage mode. The limits of quantitation (LOQs) were less than 0.9 ng/L. The method was validated through a recovery study of various environmental III samples. Concentrations of NDMA in swimming pool water samples were detected ranging 4.7 to 127.4 ng/L, and recovery ranged from 57-113% and the relative standard deviation was below 20%. This developed method is a simple and solvent-less pretreatment method to detect NDMA and other N-nitrosamines in aqueous sample.

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30

Lin, Chia-Ying, and 林佳穎. "Determination of tetramethylammonium hydroxide in mouse serum by micro solid-phase extraction combined with liquid chromatography tandem mass spectrometry." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/43gu23.

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碩士
國立中興大學
化學系所
99
A simple and sensitive method using micro solid-phase extraction (µSPE) combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) for determination trace amount of tetramethylammonium hydroxide (TMAH) in mouse serum was evaluated in this thesis. The heated electrospray ionization (HESI) with positive mode of triple quadrupole mass spectrometry was used to analyze tetramethylammonium hydroxide. Tetramethylammonium was extracted from serum by µSPE with a mixed-mode cation exchange sorbent and 0.1% trifluoroacetic acid in acetonitrile used as the eluting solvent. The volume of sample used was 15 µL. The linear range of the method was 10-2500 ng/mL with coefficient of determination at 0.9944. The limit of detection and limit of quantitation was 1.9 and 6.3 ng/mL, respectively. The intra-day and inter-day precisions with relative standard deviations were less than 2.5 and 9.8 %, respectively. The recovery of the method was greater than 95.6 %. As the matrix effect was unconsidered from the results of post-column infusion and post-extraction spiked. The feasibility of applying the proposed method to determine tetramethylammonium in serum was examined by analyzing real mouse serum sample of TMAH-exposured. The concentration of tetramethylammonium detected was range from 1.1 µg/mL to 9.1 µg/mL. The results of this study reveal the proposed method offers low ng/mL level sensitivity and high selectivity for determination of tetramethylammonium in mouse serum.

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31

Huang, Man-Chun, and 黃嫚君. "Determination of volatile N-nitrosamines in meat products by microwave-assisted extraction coupled with dispersive micro solid-phase extraction and gas chromatography-chemical ionization mass spectrometry." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/02410060324993531620.

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碩士
國立中央大學
化學研究所
100
The presence of N-nitrosamines (NAms) in food stuff has become a significant issue on Public health in last decades, NAms are throught to be mutagenic and carcinogenic with action on the liver, kidney and lung. These compounds are formed by reaction of N-containing substances. In this study, a sensitive procedure, microwave-assisted extraction (MAE) coupled dispersive micro solid-phase extraction (D-μ-SPE), was developed to extract N-nitroso- dimethylamine (NDMA) and other six volatile N-nitrosamines (NAms) from meat products. The parameters affecting the MAE and D-μ-SPE efficiency were systematically investigated. For MAE, 5-g of pasted meat sample was extracted in 30 mL sodium hydroxide (0.025 M) solution at 100 C for 10 min. The best D-μ-SPE conditions were immersing 100 mg of Carboxen 1000 adsorbent in MAE extract, after 30 min of extraction by vigorously shaking, the NAms were then desorbed by 200 μL of dichloromethane. A 10 μL aliquot was determined by gas chromatography with chemical ionization mass spectrometry (GC-CI-MS) using the selected-ion -storage (SIS) mode. The limits of detection (LODs) were 0.006−0.12 ng/g.

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32

Huang, Cheng-Chieh, and 黃正杰. "Magnetic Molecularly Imprinted Polymers for Dispersive micro Solid - Phase Extraction of Estrogens in Environmental Aqueous Samples by Liquid Chromatography-Tandem Mass Spectrometry." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/79173702146320985508.

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碩士
國立中興大學
化學系所
105
Endocrine disrupting chemicals (EDCs) in aquatic environment have gained global attention because they may interfere with central regulatory functions by antagonizing or mimicking the effects of endogenous hormones even at extremely low concentrations. In human life, the use of estrogens, the group of steroidal hormones of EDCs, in animal feeds, contraceptives, and hormone replacement therapy drugs is increasing dramatically. Estrogens enter the human living environment may cause many diseases such as breast and prostate cancers. Hence, to develop an efficiency analytical method for determination of estrogens in aquatic samples is important. This study developed magnetic molecularly imprinted polymers (mMIPs) for dispersive micro solid-phase extraction (DμSPE) combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) for characterization of trace estrogens in aquatic samples. The experimental conditions including the synthesis of mMIPs and extraction parameters were optimized. In this study, 10 mg mMIPs were placed in a 1.5 mL microtube, subsequently added 1 mL water sample pH adjusted to 8. The mixed solution was vortexed for 3 min and separated using an external magnet followed by washing with pH 8 buffer. Then added 200 μL 5% NH4OH in acetonitrile and vortexed for 1 min. After separated, the supernatant was injected into the LC-MS/MS. The linearity of the proposed method ranged from 0.1 – 50 ng/mL for estradiol (E2), 17α-Ethinylestradiol (EE2), and 0.05 – 50 ng/mL for estrone (E1), diethylstilbestrol (DES) with the coefficients of determination above 0.9968. The limit of detection (LODs) ranged from 0.4 – 1.4 pg/mL. The feasibility of applying the proposed method to determine the trace estrogens in environmental water samples of Taichung area was also examined. The trace amount of DES, E1, E2, and EE2 in environmental water were detected by proposed method at 0.92, 1.16, 0.48, and 1 ng/mL, respectively. The results showed the developed method can be successfully utilized for analyzing the trace of estrogens.

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33

Hu, Ju Ting, and 胡筑亭. "New Effervescence-Assisted Dispersive micro-Solid phase Extraction with Magnetic Molecularly Imprinted Polymeric Particles for the Determination of Phenoxy Acidic Herbicides by HPLC-UV." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/41060602768647427455.

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碩士
國立中興大學
化學系所
101
In this research, novel magnetic molecular imprinted polymers (MMIPs) particles was synthesized and utilized as a adsorbent phase for the new in-pipette tip based effervescence-assisted dispersive micro-solid phase extraction (IPT-EFA-DMSPE) combined with HPLC-UV to analyse the phenoxy acidic herbicides (2,4-dichlorophenoxyacetic acid, fenoprop, dichlorprop 2,4,5- trichlorophenoxyacetic acid) in environmental water samples. In the extraction process, effervescence was used to disperse MMIPs in the sample solution in order to substitute the use of ultrasonication process or dispersive solvent. A modified plastic pipette (5 mL) tip (which had frit on top of the tip) was prepared as an extraction device. MMIPs was synthesized by using 2,4-D as template, 4-VP and styrene (as monomer), EGDMA (as cross-linker) and AIBN (as initiator) dissolved in the solvent (methanol and water, 4/1, v/v). All the pre-polymerization solution was dissolved uniformly and then the magnetic nanoparticles were added with water-bath heating for polymerization. In the extraction procedures, firstly, MMIPs, sodium carbonate and citric acid were added into the pipette tip and followed by the addition of sample solution. During the addition of sample solution, sodium carbonate and citric acid could react to produce carbon dioxide as effervescence (bubbles) which induces the dispersion of MMIPs in the sample solution. After the extraction, a small magnet was used to collect the MMIPs and the sample solution was removed and followed by washing and elution steps. And, the eluent was dried by nitrogen, and re-dissolved with the mobile phase and inject to the HPLC-UV for analysis. Parameter affecting the experimental conditions such as the pH of the loading solution, the selection of washing solvent and eluent, the effect of ions in the solution were thoroughly optimized. Under the optimal condition, linear ranges were ranged from 0.01-8000 μg mL-1. Correlation coefficients were higher than 0.9953. Quantitation limits (LOQ) were lower than 0.02 μg mL-1.Detection limits (LOD) were lower than 0.006 μg mL-1. Precision was lower than 4.8% RSD. The new IPT-EFA-DMSPE method was applied to farmland waste water analysis. The relative recoveries were ranged between 90.6%-99.7% for spiked 50-150 ng mL-1 (phenoxy acidic herbicides) in real water samples. The results showed that the MMIPs as the adsorbent coupled with IPT-EFA-DMSPE method was a simple, rapid, selective and low cost method for the determination of phenoxy acidic herbicides in water samples. Moreover, the proposed method reduced the matrix interferences and provided high selectivity and sensitivity. Thus, this method was proven to be an alternative method to analyze the phenoxy acidic herbicides residues in the field of environmental water analysis in the future.

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34

Lin, Wei-Che, and 林偉哲. "The development of novel spray fluidized bed to technology prepare genistein imprinted micro and nano sphere for memory solid-phase extraction from soybean milk." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/29874828976184895126.

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碩士
國立成功大學
化學工程學系碩博士班
97
The purpose of this research was to replace the traditional separation process by molecular imprinting technique to separate and purify genistein from soybean milk. Genistein (4',5,7-trihydroxyisoflavone) is a phytochemical group associated with a range of potential health beneficial effects. These include chemoprevention of breast and prostate cancers, cardiovascular disease, antioxidant, and anti-osteoporotic. It is a compound that researchers have become very interested in recently. In our laboratory, we integrate molecular template, spray fluidized bed and electrostatic precipitation technology to create a novel spray fluidized bed polymerization method. This technique is to simplify processes in conventional molecular imprinted polymerization method. The concept is mixing target molecule, functional monomer, crosslinker, initiator and solvent and operating atomizer to produce aerosol. The suspension of the aerosol fluized polymerized by UV light in the quartz tube and collected on the plate by static electricity. The advantages of this method are to get independent genistein imprinted micro-nano sphere and to complete polymerization reaction efficiency. In this study, genistein was chosen as template to prepare the molecularly imprinted polymer. The batch re-binding study and isothermal titration method were introduced to investigate the optimized formulation of genistein-imprinted polymer. Comparing the results of isothermal titration and batch re-binding study, TRIM and MAA were the optimized cross-linker and functional monomer among the monomers tested in this study. The best volume ratio of MAA to TRIM is 1:8. After the polymerization, extraction and rebinding steps, the genistein molecular imprinted polymer appeared to have absorption quantity 506.59μg/g, imprinting factor 1.738. From review paper, the range of particle size is from several to hundred micrometer during fluidization. In this research, the average size of MIP can reach 90nm during spray fluidized process from ZATASIZER results. The results showed that the selectivity of genistein-imprinted polymer was 50.5 in multi-component. In the soybean milk extraction rebinding test showed that the absorption genistein quantity can reach 80.92μg/g and absorption daidzein quantity can reach 39.77μg/g. This result revealed thst the imprinted polymer exhibit selectivity and affinity for genistein.

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35

Lu, Yu-Wen, and 盧郁文. "A Novel and Rapid Method for Determination ofThiabendazole in Aqueous Samples by In-tip Molecularly Imprinted Solid phase Extraction Coupled with UV-vis micro-Spectrometer." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/mpsv84.

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碩士
國立中興大學
化學系所
102
In this study, the in-tip molecularly imprinted polymer (MIP) monolith was prepared as sorbent and applied for the extraction of thiabendazole from aqueous sample prior UV/vis micro-spectrometer determination. The molecularly imprinted polymer monolith was utilized as a sorbent phase and combined with an autopipet to extract. The extraction process can be finished by pushed and pulled with an autopipet to saving the time for in-situ analysis. MIPs was synthesized by using thiabendazole as template, 2-Acrylamido-2-methyl-1-propanesulfonic acid (AMPS) as monomer, Ethylene glygol dimethacrylate (EGDMA) as cross-linker and 2,2- Azobisisobutyronitrile (AIBN) as initiator, dissolved in the solvent (methanol and toluene) under UV for in-situ polymerization. Parameters affecting the experimental conditions such as the pH of the loading solution, or the selection of rinsing solution and eluent, were properly optimized. Under the optimal condition, the linear ranges were from 0.5-12 μg mL-1. Linear coefficient for determination was 0.9978. Detection limits (LOD) was 0.2 μg mL-1. Quantitation limits (LOQ) was 0.6 μg mL-1. Precision was lower than 10.2 % RSD. The new IT-MISPE-UV method was applied to orchard-waste water analysis. The relative recoveries were ranged between 89.5 %-96.1 % for spiked 0.5-1.5μg mL-1 (thiabendazole) in real water samples. The results showed that the MIPs as the adsorbent coupled with IT-MISPE-UV method was a simple, rapid, and low cost method for the determination of thiabendazole.

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36

Fairley, Coesha Ancoinette. "Application of Solid Phase Micro-extraction With Gas Chromatography-Mass Spectrometry for the Determination of Geosmin and 2-Methylisoborneol in Processed Navy Beans (Phaseolus vulgaris)." 2007. http://etd.utk.edu/2007/FairleyCoesha.pdf.

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37

Yo, Wo-Jun, and 游武峻. "A rapid dispersive micro-solid phase extraction with magnetic molecularly imprinted polymer for the determination of aflatoxin B1 and B2 in foods and drinks by HPLC-UV." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/06122595202800788576.

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碩士
國立中興大學
化學系所
105
In this study, a magnetic molecularly imprinted polymer (MMIP) was prepared as the sorbent to achieve dispersive micro-solid phase extraction (d-μ-SPE) of aflatoxins B1 and B2 in aqueous food samples for high performance liquid chromatography-ultraviolet detection (HPLC-UV). The magnetic particles were prepared by adding ferric chloride and ferrous chloride in 3 % NH4OH under stirring for 1 hour, and then washing by pure water. The surface of magnetic particles were then modified with tetraethyl orthosilicate (TEOS) and 3-(trimethoxysilyl) propyl methacrylate (MPS) to build-up functional groups for bonding with the MIPs which prepared by using 5,7-dimethoxycoumarin (DMC) as the template molecule, styrene and methacrylic acid (MAA) as the functional monomers, ethylene glycol dimethacrylate (EGDMA) as the cross linker, azobisisobutyronitrile (AIBN) as the initiator, and ethanol-water(4:1, v/v) as the porogen and solvent, Parameters influenced the extraction efficiencies of aflatoxins B such as synthesis of MMIP, sample pH, salting out effect, and solution for eluting were investigated thoroughly and optimized. After a series of tests, for a 10 mL aqueous sample solution at pH 7.0 the best extraction efficiency was obtained by using MMIP-d-μ-SPE to collect aflatoxins B for 10 min under 800 rpm stirring, and then using a magnet to separate the MMIPs particles from matrix solution. After rinsing with water, aflatoxins B were desorbed with acetonitrile for HPLC-UV analysis. Under the optimal condition, the detections were linear in 0.2 - 25 ng/mL with correlation coefficients above 0.9986 for both aflatoxin B1 and B2. The detection limits (based on S/N = 3) were 0.04 ng/mL and quantitative limits (based on S/N = 10) were 0.1 ng/mL for both aflatoxin B1 and B2. The aflatoxin B1 and B2 in milk and spiked samples were analyzed with the present method and characterized by mass spectrometry. Recoveries were ranged 89.5 – 102.9 % with relative standard deviations of less than 7.0 %. The prepared MMIP is stable and can be used for over 50 times. These results have proven the proposed MMIPs-d-μ-SPE method is a simple, rapid, selective, and eco-friendly sample pretreatment method to extraction aflatoxins in aqueous samples for HPLC-UV analysis.

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38

Chen, Yu-Shin, and 陳淯信. "New In-tube Dispersive Micro-solid-phase Extraction Coupled Electrostatic-Assisted Collection of Sulfonated Graphene for the Determination of Polycyclic Aromatic Hydrocarbons in Aqueous Samples by GC-MS." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/60122255363170424727.

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碩士
國立中興大學
化學系所
101
In this work, a new rapid dispersive micro-solid phase extraction (DMSPE) technique coupled electrostatic-assisted collection of sulfonated graphene nanosheets (sGNS) followed by gas chromatography-mass spectrometry (GC-MS) for the determination of polycyclic aromatic hydrocarbons (PAH) in aqueous samples was developed. In this method, water soluble sulfonated graphene nanosheets was synthesized and utilized as nano-sorbent for the extraction of PAH and a newly designed home-made glass extraction device was adopted to collect the negatively charged sGNS based on the electrostatic migration by applying positive high voltage. Parameters affecting the proposed extraction method was thoroughly examined and optimized. The maximum extraction efficiency was obtained under the selected condition as follows; 8 mL of aqueous sample (pH 6) with 1 mg of sGNS were taken in the extraction device and 30 kV was applied to collect sGNS and followed by desorption using 10μL of toluene under ultrasonication for 15 min. Under the optimal conditions, the liner ranges were 1-1000 μg/L for naphthalene, acenaphthylene and acenaphthene, 2-2000 μg/L for fluorine, phenanthrene, anthracene, fluoranthene, pyrene and 3-3000 μg/L for benzo(a)anthracene and chrysene. Detection limits were achieved at level of 0.3-0.9 μg/L and the limit of quantitation were 1.0-3.2 μg/L. The relative recoveries of river samples were between 82.3-117.7 % and RSD were below 8.1%. The results demonstrated that the proposed method was a simple, rapid, sensitive, low cost and eco-friendly approach for the determination of PAH in aqueous samples.

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39

Ferreira, Elisa Gabriela Monteiro. "A Validated Methodology for the Forensic Toxicological Analysis of Opioids in Biological Fluids Using Solid Phase Extraction, Microwave Derivatization and Gas Chromatography-Mass Spectrometry." Master's thesis, 2019. http://hdl.handle.net/10316/87930.

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Dissertação de Mestrado em Química Forense apresentada à Faculdade de Ciências e Tecnologia
O desenvolvimento do presente estudo tornou-se pertinente devido ao consumo indevido de opióides e ao número de mortes por overdoses associadas ao seu consumo, tanto em Portugal como no resto do mundo. Por outro lado, sendo o recurso a matrizes biológicas postmortem alternativas ao sangue, uma área de crescente interesse em toxicologia forense estudámos a viabilidade do uso do líquido pericárdico na determinação das substâncias selecionadas.Assim, o objetivo deste trabalho foi o desenvolvimento, otimização e validação de uma metodologia analítica para a determinação qualitativa e quantitativa de alguns opióides em sangue e líquido pericárdico.Os opióides estudados foram: morfina, codeína, 6-acetilmorfina, 6-acetilcodeína, oxicodona, oximorfona e o fentanil.O estudo incluiu a otimização do procedimento analítico e do método cromatográfico. Otimizámos a extração em fase sólida (SPE), a derivatização com e sem recurso a hidroxilamina aquosa a 1% e o tempo de derivatização induzida por micro-ondas com o reagente químico MSTFA (n-metil-n-(trimetilsilil) trifluoroacetamida)+5% TMCS (trimetilclorosilano).O método mais eficiente e seletivo correspondeu ao seguinte procedimento: precipitação com acetonitrilo de volumes de 250 μL de amostras de sangue e de líquido pericárdico, derivatização das substâncias de interesse usando 1% hidroxilamina aquosa em PBS (1:2, v/v) promovida por irradiação de micro-ondas, durante 30 segundos com uma potência de 900 W a 50%. Procedeu-se à extração dos analitos de interesse por SPE. Após evaporação dos eluatos (sob corrente de azoto a 40 ᵒC) os extratos foram derivatizados com MSTFA+5% TMCS sob ação de micro-ondas durante 100 segundos com uma potência de 900 W a 100%. Seguidamente os extratos derivatizados foram injetados (2 μL, splitless) diretamente no sistema de cromatografia de gases associado à espectrometria de massas (GC-MS-EI) com monitorização dos iões selecionados (modo SIM) e com o forno à temperatura inicial de 50 ᵒC.Após a otimização, o método foi validado seguindo as normas da Scientific Working Group for Forensic Toxicology (SWGTOX) de forma a garantir que o método é adequado para os fins a que se destina e assim atestar a sua fiabilidade na interpretação dos resultados analíticos. O método apresentou linearidade no intervalo 5-1000 ng/mL com coeficientes de determinação superiores a 0.99 para todos os analitos. Os limites de deteção (LOD) variaram entre 3 e 4 ng/mL, dependendo da substância e/ou da matriz analisada e os limites de quantificação (LOQ) foram de 5 ng/mL para todas as substâncias. Em relação às precisões (intra-dia e intermédia) todos os níveis de concentração apresentaram valores de CV <20% e a exatidão situou-se dentro do intervalo ±20%.Verificou-se ainda que as substâncias apresentaram estabilidade sob as seguintes condições: nos extratos deixados no amostrador em condições ambientais por pelo menos 24 h; nas amostras de sangue e líquido pericárdico deixadas na bancada de trabalho durante 4 h e nas amostras de líquido pericárdico durante 3 ciclos de congelação e descongelação ao longo de pelo menos 4 semanas.Por fim, a metodologia analítica foi aplicada a amostras reais disponibilizadas pelo Serviço de Química e Toxicologia Forenses da Delegação do Centro do Instituto Nacional de Medicina Legal e Ciências Forenses, I.P..De acordo com a revisão bibliográfica efetuada, este foi o primeiro método desenvolvido para a deteção e quantificação simultânea deste grupo de substâncias em sangue e líquido pericárdico com recurso à derivatização promovida por micro-ondas com os reagentes químicos hidroxilamina e MSTFA+5% TMCS.
The development of the present study became pertinent due to the misuse of opioids and the number of overdose deaths associated with its use, both in Portugal and in the rest of the world. On the other hand, being the use of alternative biological matrices to postmortem blood, an area of growing interest in forensic toxicology, we studied the feasibility of using pericardial fluid in the determination of the selected substances.Thus, the objective of this work was the development, optimization and validation of an analytical methodology for the qualitative and quantitative determination of some opioids in blood and pericardial fluid.The opioids studied were: morphine, codeine, 6-acetylmorphine, 6-acetylcodeine, oxycodone, oxymorphone and fentanyl.The study included the optimization of the analytical procedure and the chromatographic method. We have optimized solid phase extraction (SPE), derivatization with and without 1% aqueous hydroxylamine and microwave derivatization time with the chemical reagent MSTFA (n-methyl-n-(trimethylsilyl) trifluoroacetamide)+5% TMCS (trimethylchlorosilane).The most efficient and selective method was as follows: precipitation with acetonitrile of 250 μL volumes of blood and pericardial fluid samples, derivatization of the substances of interest using 1% aqueous hydroxylamine in PBS (1:2, v/v) with microwave action for 30 seconds with a power of 900 W at 50%. The samples were cooled and then the analytes of interest were extracted by SPE. After evaporation of the eluates (under nitrogen stream at 40 °C) the extracts were derivatized with MSTFA+5% TMCS under microwave action for 100 seconds with a power of 900 W at 100%. Then the derivatized extracts were injected (2 μL, splitless) directly into a gas chromatography mass spectrometry system (GC-MS-EI) with selective ion monitoring mode (SIM mode) and with the oven at the initial temperature of 50 °C.After optimization, the method was validated following the standards of the Scientific Working Group for Forensic Toxicology (SWGTOX) to ensure that the method is suitable for its intended purpose and thus attest to its reliability in interpreting the analytical results. The method presented linearity in the range 5-1000 ng/mL with coefficients of determination above 0.99 for all analytes. The limits of detection (LOD) ranged from 3 to 4 ng/mL, depending on the substance and/or matrix analysed and the limits of quantitation (LOQ) were 5 ng/mL for all substances. Regarding the precision (intra-day and intermediate) all concentration levels presented CV values <20% and the bias was within ±20%. It was also verified that the substances presented stability under the following conditions: in the extracts left in the autosampler under environmentalconditions for at least 24 h; blood and pericardial fluid samples on the workbench for 4 h; pericardial fluid samples for 3 freeze-thaw cycles for at least 4 weeks.Finally, the analytical methodology was applied to real samples provided by the Serviço de Química e Toxicologia Forenses da Delegação do Centro do Instituto Nacional de Medicina Legal e Ciências Forenses, I.P. (Forensic Chemistry and Toxicology department of the Centre Branch of the National Institute of Legal Medicine and Forensic Sciences, I.P.).According to the literature review, this was the first method developed for the simultaneous detection and quantification of this group of substances in blood and pericardial fluid using microwave induced derivatization with the chemical reagent’s hydroxylamine and MSTFA+5% TMCS.

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