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1
Haider, Waqar. "Caractérisation de la composition physico-chimique de pommeaux de Normandie : Détermination de la composition volatile par chromatographie en phase gazeuse après extractions par SPE et MEPS." Caen, 2012. http://www.theses.fr/2012CAEN2078.
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Cette étude constitue, à notre connaissance, la première caractérisation physico-chimique complète des « Pommeaux de Normandie ». Ils possèdent un titre alcoométrique moyen de 16,3% (v/v) et un pH compris entre 3,7 et 4,1. Les acidités totale et volatile y sont assez faibles et corrélées à de faibles quantités en acide malique (environ 1,6 g. L-1) ainsi qu’à des concentrations assez fortes en sucres réducteurs (79-109 g. L-1). Les métaux alcalins et alcalino-terreux (K, Ca, Na, Mg) sont les éléments les plus concentrés. De faibles contenus en métaux de transition (Zn, Pb, Cu, Fe) sont retrouvés dans les échantillons les plus limpides. 124 composés organiques volatils (COVs) ont été identifiés par GC-MS après SPE et fractionnements par chromatographie sur colonne. Le potentiel de deux méthodes a été comparé pour doser 14 composés majeurs par GC-FID. La SPE (support terre de diatomées) s’est avérée être relativement imprécise. Au contraire, la MEPS (adsorbant C18) a été démontrée comme étant répétable (1,5 à 8%). Au préalable, une étape d’optimisation a consisté à évaluer le solvant le plus adapté pour l’élution (dichlorométhane) et le nombre adéquat d’extraction par échantillon (4x100 L). Cette dernière méthode a été validée et des limites de détection très faibles (autour de 10 g. L-1) ont pu être trouvées notamment pour les composés hydrophobes. Nous avons pu démontrer que la plupart des COVs proviennent de l’addition de Calvados lors de l’élaboration des Pommeaux. Les alcools supérieurs y sont prédominants (environ 800 mg. L-1) et leur présence est généralement corrélée à l’avancement de la fermentation alcoolique des cidres servant à élaborer les Calvados. Cette étude constitue, à notre connaissance, la première caractérisation physico-chimique complète des « Pommeaux de Normandie ». Ils possèdent un titre alcoométrique moyen de 16,3% (v/v) et un pH compris entre 3,7 et 4,1. Les acidités totale et volatile y sont assez faibles et corrélées à de faibles quantités en acide malique (environ 1,6 g. L-1) ainsi qu’à des concentrations assez fortes en sucres réducteurs (79-109 g. L-1). Les métaux alcalins et alcalino-terreux (K, Ca, Na, Mg) sont les éléments les plus concentrés. De faibles contenus en métaux de transition (Zn, Pb, Cu, Fe) sont retrouvés dans les échantillons les plus limpides. 124 composés organiques volatils (COVs) ont été identifiés par GC-MS après SPE et fractionnements par chromatographie sur colonne. Le potentiel de deux méthodes a été comparé pour doser 14 composés majeurs par GC-FID. La SPE (support terre de diatomées) s’est avérée être relativement imprécise. Au contraire, la MEPS (adsorbant C18) a été démontrée comme étant répétable (1,5 à 8%). Au préalable, une étape d’optimisation a consisté à évaluer le solvant le plus adapté pour l’élution (dichlorométhane) et le nombre adéquat d’extraction par échantillon (4x100 L). Cette dernière méthode a été validée et des limites de détection très faibles (autour de 10 g. L-1) ont pu être trouvées notamment pour les composés hydrophobes. Nous avons pu démontrer que la plupart des COVs proviennent de l’addition de Calvados lors de l’élaboration des Pommeaux. Les alcools supérieurs y sont prédominants (environ 800 mg. L-1) et leur présence est généralement corrélée à l’avancement de la fermentation alcoolique des cidres servant à élaborer les CalvadosThis study focused on the first physico-chemical characterization of “Pommeaux de Normandie”. Pommeau is a traditional beverage from Normandy which is elaborated by mixing Calvados (1/3) and apple must (2/3). We showed that it contains a mean content of ethanol around 16. 3% (v/v) and a pH between 3. 7 and 4. 1. Total and volatile acidities are rather low if they are compared to other beverages; this is correlated with relatively low quantities of malic acid (around 1. 6 g. L-1) and relative high concentrations of reducing sugars (79-109 g. L-1). It reflects that producers are selecting higher proportions of sweet apples and lower proportions of acidic apples than for apple musts devoted to be transformed in commercialized ciders. Alkali and alkaline earth metals (K, Na, Ca, Mg) are the highest concentrated elements. A low content of transition metals (Zn, Pb, Cu, Fe) in the beverage seems to be correlated with a low turbidity of samples. The presence of 124 volatile organic compounds (VOCs) was determined in Pommeau samples by GC-MS after Solid Phase Extraction (SPE) and column chromatographic fractionations using a specific procedure of identification. 14 major VOCs were selected to be quantified. With the help of GC-FID analyses, the ability of two methods of sample preparation was compared to achieve this goal. SPE using diatomaceous earth as solid support was found to give imprecise results of concentration. On the contrary, Microextraction by Packed Sorbent (MEPS) using a C18 sorbent was repeatable (between 1. 5 and 8%). This was determined after a step of optimization of the method which consisted in selecting the most suitable solvent of elution (dichloromethane) and the adequate number of extraction of Pommeau samples (4x100 µL). The MEPS method was validated and exhibited low limits of detection mainly for hydrophobic compounds which can be detected at concentrations around 10 µg. L-1. After comparison of the contents in major VOCs of Pommeau and ciders, we showed that most of the VOCs of Pommeau are issuing from the addition of Calvados. Higher alcohols are predominant (around 800 mg. L-1) and, except butan-1-ol and hexan-1-ol, their presence in Pommeau is correlated to the extent of the alcoholic fermentation of ciders used to elaborate Calvados
2
Vydrová, Lucie. "Využití separačních metod pro studium biologicky aktivních látek ve vodách." Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2011. http://www.nusl.cz/ntk/nusl-233344.
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Pharmaceuticals are biological active compounds with different functional groups, physico-chemical and biological properties. These chemical compounds are called as “new contaminants” which cumulate in various environmental components. These contaminants input to environment from industrial processes, hospitals and health care institutions or household sources and these pollutants can to negatively interact with environmental components. Pharmaceuticals are separated according to structure and their effects to live organisms. On the basis of drug consumption in Czech Republic the non-steroidal anti-inflammatory drugs are the most using pharmaceuticals, because these drugs can be obtain without prescriptions. The choosing analgesics for study were monitored in waste water from waste waters treatment plant (WWTP Brno – Modřice) and in surface water from two sampling sites of river Kretinka. Pharmaceuticals were monitored in surface waters in Czech Republic, in Scotland (river Thurso) and in Taiwan (river Erren, Agongdian, Yanshuei and canal of Tainan) Solid phase extraction (SPE) is used for extraction of study pharmaceutical from water system. The high performance liquid chromatography (HPLC) with diode array detection or mass spectrometry was used for determination of drugs in surface waters from Czech Republic. The water samples from Scotland and Taiwan were analysed and the high performance liquid chromatography with mass spectrometry (HPLC/MS) was used for determination of pharmaceuticals. The method of HPLC/MS enables the determination of study compounds in the very low range of concentrations (ng ? l-1). All monitored pharmaceuticals were identified and quantified in water samples from river Kretinka in Czech Republic, river Thurso (Scotland) and rivers Erren, Agongdian, Yanshuei and canal of Tainan in Taiwan and the obtained data were compared.
3
Karlsson, Tufuga Anna. "Extraction efficacy of oil samples in forensic investigations using solid phase extraction (SPE)." Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-84464.
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This study aims to complement the internationally implemented method “CEN/TR 15522-2: 2012 WATERBORNE PETROLEUM AND PETROLEUM PRODUCTS - PART 2” (CEN). It is a method for forensic investigations on oil spill identification using gas chromatography coupled with low resolution mass spectrometry in electron ionisation mode (GC-EI-MS), in single ion monitoring mode (SIM). The method uses hydrocarbon fingerprints and biomarker abundances to compare oils from spill sources with oil from suspected sources. This method is implemented by the national forensic centre (NFC) with their main object to perform and develop forensic investigations for successful law enforcement. The experiment uses four different matrices common within the NFC department: wood ash, soil, fabric and cotton swabs. The method evaluates how different sample preparation and clean-up techniques can extract crude oil and heavy fuel oil without losing important information such as the relative abundance of so-called biomarkers typically looked for in international standard praxis in forensic investigations. In conclusion the implemented CEN method showed a reasonably good extraction from matrixes. Extraction of biomarkers were generally quantitative. Extractions of PAHs worked best in soil and cotton swab matrices. In ash samples, the extraction was not very efficient (between 20-80%). It seems that the PAHs strongly bind to active coal in the ash and cannot be extracted fully. It was also evident that the fabric matrix used was problematic for PAH extraction. The fabric itself seemed to release compounds which interfere with the analysis. In soil samples, 31abR (a biomarker compound) was a reoccurring interference from the matrix. Furthermore, analysis of isoprenoids and alkanes had a very broad analytical variation, seen by that the analytical response for these compounds vary greatly among different samples. SPE-extractions did not work well enough following the protocol in this study to be included as a sample preparation step at the moment. More optimization would be needed before the method could be included as an implemented method.
4
Gulamussen, Noor Jehan. "Electrospun sorbents for solid phase extraction (SPE) and colorimetric detection of pesticides." Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1013241.
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The thesis presents the evaluation of polysulfone sorbents for solid phase extraction (SPE) and the development of colorimetric probes for pesticides analysis in water. Through electrospraying and electrospinning techniques, different morphologies of sorbents (particles, beaded fibers and bead-free fibers) were fabricated. The sorbents were morphologically characterized by scanning electron microscopy. Adsorption capacities of sorbents were evaluated by conducting recoveries studies for model pesticides; atrazine, chlorpyrifos and DDT using batch and column SPE modes. Better recovery results were achieved by employing the batch mode of fibers, as values ranged from 98 to 105percent. Further sorbent evaluation was conducted using breakthrough experiments and static experiments. The breakthrough studies indicated that 1700 μL was the sample volume that could be percolated with no breakthrough of the analyte that correspond to a concentration of 150 mg/g of sorbent that can be extracted without any loss of analyte. From static studies, quantities of each model compound adsorbed into the fiber at the equilibrium time were evaluated. The adsorbed atrazine was 65, chlorpyrifos 250 and DDT 400 mg/g of sorbent. Kinetic studies suggested retention mechanism following pseudo first and second order model observed by high correlation coefficients (> 0. 96), demonstrating the fiber affinity to retain both polar and non-polar compounds opening a possibility to be used as sorbent for sample preparation of different classes of pesticides in water. For the second part of the study simple strategies for colorimetric sensing based on silver nanoparticles and polivinylpyrrolidone capped nanoparticles were developed, respectively for atrazine and chlorpyrifos detection. The limits of detection of the methods were 3.32 and 0.88 mg/L for atrazine and chlorpyrifos respectively. The applicability of the probe in real samples was demonstrated by the recoveries studies of tap water varying from 94 to 104 percent. The versatility of the probe was demonstrated by affording a simple, rapid and selective detection of atrazine and chlorpyrifos in the presence of other pesticides by direct analysis without employing any sample handling steps. Attempt to incorporate the probes in a solid support was achieved by using nylon 6 as solid support polymer proving to be fast and useful for on-site detection.
5
Sibali, LL, JO Okonkwo, and C. Zvinowanda. "Determination of DDT and Metabolites in Surface Water and Sediment Using LLE, SPE, ACE and SE." Springer Science, 2009. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1001502.
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Abstract
Surface water and sediment samples collected
from Jukskei River in South Africa, were subjected to
different extraction techniques, liquid–liquid (LLE), solidphase
extraction (SPE), activated carbon extraction (ACE)
and soxhlet extraction (SE) for sediment. The samples were
extracted with dichloromethane, cleaned in a silica gel
column and the extracts quantified using a Varian 3800
GC-ECD. The percentage recovery test for 2,40DDT, DDE
and DDD and 4,40DDT, DDE and DDD in water ranged
from 80%–96% and 76%–95% (LLE); 56%–76% and
56%–70% (SPE) and 75%–84% (ACE), respectively; while
that recoveries for sediment samples varied from 65%–
95% for 2,40DDT, DDE and DDD and 80%–91% for
4,40DDT, DDE and DDD. The high recoveries exhibited by
ACE compared very well with LLE and SE. This was not
the case with SPE which exhibited the lowest value of
recoveries for both 2,4 and 4,40DDD, DDE and DDT
standard samples. The mean concentrations of DDT and
metabolites ranged from nd-1.10 lg/L, nd-0.80 lg/L, nd-
1.21 lg/L and 1.92 lg/L for LLE, SPE, ACE and SE,
respectively. The total DDT (2,40 and 4,40-DDT) in water
and sediment samples ranged from 1.20–3.25 lg/L and
1.82–5.24 lg/L, respectively. The low concentrations of
the DDT metabolites obtained in the present study may
suggest a recent contamination of the river by DDT.
6
Johansson, Elias. "Pressure-based clog detection in SPE-columns." Thesis, Uppsala universitet, Institutionen för elektroteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-446697.
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The concept of integrated sensors in the Biotage® Extrahera™ system to perform live-monitoring of pressure inside SPE-columns is investigated. A test-rig containing the components necessary to simulate the pressure-cycle in the system is constructed and a printed-circuit board assembly is designed and implemented into its 24-column format. Liquid samples with varying viscosity are then synthesized using water and glycerol, which are used in a simplified 2-step SPE-process during which the pressure inside the columns is logged. The results obtained showed that the concept is viable and methods for clog detection as well as state assessment are discussed. However, it was established that the solution needs further testing involving complete SPE-processes with real samples before any detailed algorithms can be presented. A pre-study is finally done regarding solutions for minimizing the design to allow for implementation into the system's more spatially restricted 96-column format.
7
Green, Caroline Elizabeth. "An experimental and modelling investigation into the solid-phase extraction of pollutants from water." Thesis, University College London (University of London), 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322408.
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Chang, Aamanda. "Optimization of solid-phase extraction (SPE) as sample preparation for oil samples in forensic investigations." Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-93375.
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Oil spills, especially in water have happened throughout the years. The consequences from this kind of incident have always been a threat to marine life and take a lot of money and time to clean up. The forensic investigations of oil usually focus on oil spill in water, however, this kind of investigation can be applied on more areas, such as in sexual offense cases and arson. The oil from the crime scene and the oil from the suspected source are analyzed and compared to each other to see if the compositions match. The aim of this thesis was to optimize the clean-up process of heavy fuel oil (HFO) using solid-phase extraction (SPE) according to the European Committee for standardization (CEN) 15522-2 method. HFOs are black oils, containing particles and soot which will decrease injector performance. Thus, a cleanup procedure is attractive when analyzing such samples. The three factors of optimization in this study were elution volumes, solvents, and SPE sorbents.The SPE method used in this study was to use the cartridges as a filter; therefore, the samples were both loaded and eluted with an organic solvent, in this case dichloromethane (DCM) or dichloromethane/heptane (DCM/Hp). The gas chromatography mass spectrometry (GC-MS) analysis method used is described in Annex B in the CEN 15522-2 method.Concluding, increasing the eluent volume did not indicate improvement on the extraction method. In terms of the solvents, both dichloromethane and dichloromethane/heptane showed similar results. The percentage weathering plots (PW-plots) showed that the SPE sorbents (dual layer florisil/Na2SO4, florisil and silica gel sorbents) worked similar. The overall conclusion from this thesis work was that further optimization must be made before implementing the method.
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Blankenship, Donna A. "Evaluation of SPEC®•Microcolumns for the extraction of ranitidine from urine." Thesis, Virginia Tech, 1994. http://hdl.handle.net/10919/44600.
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Ismailov, Taner. "Quantification of resin acids, fatty acids and sterols in process and waste water from forest industry." Thesis, Karlstads universitet, Avdelningen för kemi och biomedicinsk vetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-28179.
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This work focuses on wood extractives in effluents from the CTMP plant at Skoghall Mill. Pulp and paper industry effluents contain mostly natural compounds which are part of the trees. They are toxic to aquatic life but harmless in nature, as they are present in low concentrations. Processing tons of wood, such as in a pulp mill, strongly increases the concentrations of the toxic compounds (Ali, M. and Sreekrishnan, T., 2001) which have to be treated before transferring to the aquatic environment.Extractives can be found in different forms, as micelles soluble in water, unprocessed in fibers or absorbed on the surface of fibers. It is important to know in which forms extractives are mostly present in the effluent, so that they can be treated more efficiently. It is desired to have extractives absorbed on the fibers and fibrils present in the waste water, so they can be separated from the water and treated separately, e.g. burned for energy recovery. Dissolved extractives complicate the oxygen transfer in an aerated biological treatment step with their surface active properties (Sandberg, 2012).The aim of this study is quantification of extractives on the fibers suspended in the waste water and extractives dissolved in the water. The distribution between the two forms is an important input when designing future effluent treatment. Wood extractives itself are a wide group with different compounds. This work focuses on the main groups present in waste water: resin acids, free and esterified fatty acids and, free and esterified sterols. These groups are analyzed in different process waters and waste water before the waste water treatment plant. The measured concentrations of extractives were as expected, higher in process and effluent waters, lower in white water. Most of the extract was dissolved in the water and unfortunately fiber samples contained very low concentration from the total extract in the samples.
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Gazda, Daniel Bryan. "Development of colorimetric solid Phase Extraction (C-SPE) for in-flight Monitoring of spacecraft Water Supplies." Washington, D.C. : Oak Ridge, Tenn. : United States. Dept. of Energy. Office of Science ; distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2004. http://www.osti.gov/servlets/purl/835309-K3fMzj/webviewable/.
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Bartuma, Ninorta. "Optimizing purification of oligonucleotides with reversed phase trityl-on solid phase extraction." Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-76844.
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Oligonucleotides are synthetic strings of DNA or RNA used mostly for biochemical analysis and diagnostics. For them to be useful in these fields, a purity over 90% is most often required. However, when synthesizing these sequences, many “failures” (shorter sequences) are made in the step-wise process. The synthesized oligonucleotides need to therefore be purified. This is most often done with gel electrophoresis or liquid chromatography. These methods are, on the other hand, very time-consuming and laborious. Solid phase extraction (SPE) is a much faster purification method if optimized and it can be done with the standard cartridges as well as 96-well plates, that allow many samples to efficiently be run at the same time. With reversed phase (RP) SPE, the dimethoxytrityl (DMT) group, that is attached to the target at the final synthesis step, can be used for stronger retention to the bed sorbent and leaving only the target at the final eluting stage. The impurities without a DMT-on group, that do not adsorb to the sorbent, are washed away in earlier steps. The purpose of this study is to optimize an SPE method for purification of oligonucleotides. Two different cartridges, Clarity QSP (Phenomenex) and Glen-Pak (Glen Research) were used. The purity analysis and oligonucleotide identification were done using anion exchange - high performance liquid chromatography (AIE-HPLC) and time-of-flight mass spectrometry (TOF MS). To conclude, Clarity QSP achieved, at the most, a purity of 68.8% with the recommended SPE steps by Phenomenex. Alterations in the extraction procedure resulted in similar purity or lower. Glen-Pak reached a peak purity of 78.8% when doing a double salt wash of 5% ACN in 2 M sodium chloride and another double wash after detritylation with 1% acetonitrile. This method has to be further optimized in order to reach a purity of at least 90% to be useful in industrial settings.
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Morrison, Erin R. "Can We Re-use “Single-Use” Solid Phase Extraction Cartridges?" Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/7065.
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Organic and inorganic compounds are present as contaminants in varying concentrations throughout our water cycle. Examples of these contaminants include the endocrine disrupting compounds (EDCs) bisphenol-A (BPA) and 17β-estradiol (E2) from plastics and pharmaceutical use. It can be necessary to obtain the concentration of these compounds within the water cycle for analysis by interested parties such as research groups, regulatory agencies, and private organizations. These concentrations, however, can be too dilute within the initial sample for analysis. Therefore it is necessary to concentrate the compound of interest (analyte) prior to analysis. One such way to do this is by way of Solid Phase Extraction (SPE).
SPE uses a small cartridge which contains chromatographic packing material to chemically extract analytes from a water sample onto a solid phase. To increase concentration, these analytes are then transferred (eluted) to a substantially smaller volume of organic solvent for eventual analyses. These commercially available cartridges are relatively inexpensive, approximately $5 each. However, these cartridges are labeled as single use. In large-scale analyses, this can quickly add up to a sizable percentage of the analysis budget. Additionally, sizable waste volumes can be generated from these analyses in the form of non-degradable polypropylene plastic. If these cartridges can be re-used, material costs as well as waste volumes can be substantially reduced. However, little is known regarding how the quality of analysis degrades with cartridge re-use. The objective of this project is to evaluate the number of times SPE cartridges can be reused without compromising the results of the subsequent analyses.
Based on a review of prior literature, I identified and developed protocols for extracting analytes (BPA and E2) from water via SPE, then analyzing them with gas chromatography and mass spectrometry (GC-MS). These protocols have been developed to mimic those employed by research labs, industry, and other entities for which the results of this study would be most applicable. The only deviation is the re-use of the cartridge rather than disposal and replacement. One type of commercially available SPE cartridge (Oasis HLB, Waters Inc., Milford, MA) was used and two water types were tested. The water was spiked with fixed concentrations of BPA and E2, and then analyzed by way of SPE/GC-MS. For both water types, I performed multiple SPE runs on 10 cartridges each. I tracked the history of GC-MS peak areas, which indicate apparent analyte concentration. Peak area data were analyzed as a function of the number of analyses performed (run number), and evaluated for statistically significant changes as well as overall trends. Statistically significant change and/or trends would indicate that the cartridge had exceeded the maximum allowable number of re-uses and would thereby identify the number of times the “single-use” cartridge can reliably be re-used.
Peak area history for 20 SPE runs per cartridge for pure water samples and 10 SPE runs for wastewater effluent showed no statistically significant changes or trends on peak area. This indicates that cartridges can be re-used at least 10 times without compromising the integrity of water sample analysis for the EDCs considered in this study.
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Grossi, Paula. "Desenvolvimento e aplicação de técnicas miniaturizadas de preparo de amostras para análises ambientais via GC-MS." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/75/75132/tde-07102009-103813/.
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Este trabalho apresenta o desenvolvimento e aplicação de técnicas miniaturizadas de preparo de amostras para análises ambientais via GC-MS. Dentre elas aplicou-se a técnica de Extração em Fase Sólida (SPE) na análise do regulador de crescimento de plantas, paclobutrazol (PBZ), em amostras de solo. Um método foi desenvolvido, otimizado e validado para o emprego da técnica acoplada à cromatografia gasosa e espectrometria de massas (GC-MS) na análise de PBZ em solo. Foram desenvolvidas também barras in-house, para Extração por Sorção em Barras de Agitação (SBSE), preparadas com PDMS, otimizadas, validadas e aplicadas na extração de pesticidas organoclorados no modo headspace acoplado a GC-MS. Adicionalmente, novos recobrimentos para SBSE a partir da modificação do PDMS comumente utilizado visando mudanças nas características de polaridade das fases sortivas foram desenvolvidos. Seguindo a tendência de miniaturização desenvolveu-se um novo sistema nomeado de Extração Sortiva Refrigerada (RSE), a qual considera a teoria de equilíbrio da HSSE e da SPME refrigerada. A técnica foi otimizada e aplicada em amostras de água do rio de Atibaia, coletadas na região de Paulínia-SP.This study describes the development and application of different miniaturized sample preparation techniques for environmental analysis via gas chromatography and mass spectrometry (GC-MS). Among those techniques, the Solid Phase Extraction (SPE) was applied to the analysis of plant growth regulator, called paclobutrazol (PBZ), in soil samples. A method was developed, optimized and validated for the application of the technique coupled to GC-MS for the analysis of PBZ in soil. In-house Stir Bar Sorptive Extraction (SBSE) was also developed, optimized, validated and applied to organochlorine pesticides extraction in water samples in headspace mode followed by GC-MS. Additionally, new coatings for SBSE based on the PDMS modification commonly used to change the polarity characteristics of the sorptive phases were developed. Following the miniaturization trend, a new system called Refrigerated Sorptive Extraction (RSE) was successfully developed. This system was built with similar refrigerated SPME and HSSE equilibrium. Such technique was optimized and applied on water samples from Atibaia´s river, collected in the region of Paulínia-SP.
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Meskar, Mahmoud. "Treatment of Petroleum Contaminated Soil using Supercritical Fluid Extraction (SFE) Technology." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/37393.
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In Canada, about 60% of contaminated sites involve petroleum hydrocarbon (PHC) contamination and most of these sites have been abandoned due to contamination. Among current technologies used for soil remediation, supercritical fluid extraction (SFE) is a relatively recent and potentially viable method. The main aim of this research was to investigate the application of SFE for removal of PHCs from contaminated soils.
In the first phase, the effects of SFE operational parameters including fluid pressure, fluid temperature, time duration and mode of extraction on the removal efficiency of PHCs from a spiked sandy soil (with diesel fuel with a ratio of 5 wt%) were investigated. SFE experiments were performed at different pressures (15, 33 and 50 MPa) and temperatures (30, 75 and 120 °C). The combination of 10 min static mode followed by 10 min dynamic mode, repeated for 3 cycles (60 min in total) led to the highest PHC removal percentage. According to response surface methodology (RSM), the optimum pressure and temperature were found to be 50 MPa and 69.3 °C, respectively. According to experimental results, the optimum combination of pressure and temperature determined to be 33 MPa and 75 °C; which resulted in the extraction percentages of 99.2%, 91.7% and 86.1% for PHC F2, F3 and F4 fractions, respectively.
In the second phase, the influence of several parameters including soil water content, soil pH and addition of modifier on PHCs removals from a field-contaminated sandy soil using SFE were experimentally investigated. SFE experiments were performed at 33 MPa pressure and temperatures of 45 and 75 °C. Three water content levels of 8%, 14% and 20% at two levels of pH 6.5 and 7.5 were investigated. The extraction of total petroleum hydrocarbon fractions (TPHF), the sum of F2, F3, and F4 fractions, decreased due to the increase in the water content from 8% to 20% at both pH 6.5 and 7.5. The difference of extractions of all PHC fractions at pH values of 6.5 and 7.5 were not statistically significant (at p < 0.05 confidence level) at all three water content levels and pH did not have a significant influence on the PHC removal efficiency. Addition of acetone as a modifier (33.7% TPHF removal) was more effective than hexanes (24.3% TPHF removal) to decrease the concentrations of PHCs for the field contaminated soil.
In the third phase, the influence of soil texture and grain size on the extraction of PHC fractions was investigated. SFE experiments were performed at 33 MPa pressure and 75 °C temperature. Three types of soils (soil A, B and C) were spiked with diesel fuel with a ratio of 5 wt%. Soil A, B and C had different particle sizes and were categorized as sand, silt loam and clay, respectively. Soil A (sand) which had the largest particle size resulted in the highest TPHF removal percentage while soil C (clay) with the smallest particle size led to the lowest TPHF removal percentage. A higher clay content in soil C resulted in a lower extraction of PHCs.
In the fourth phase, the effects of pressure and temperature on the extraction of PHC fractions from a clay soil spiked with diesel fuel with a ratio of 5 wt% were investigated. SFE experiments were performed at three pressures (15, 33 and 50 MPa) and temperatures (30, 75 and 120 °C). According to the statistical analysis including factorial design and RSM, the optimized combination of pressure and temperature was selected at 42.8 MPa and 120 °C; which resulted in the removal percentages of 74.9% and 65.6% for PHC F2 and F3 fractions, respectively. The optimum combination of pressure and temperature based on the experimental results was selected at 33 MPa and 120 °C that led to 70.3%, 58.4% and 32.6% removal of PHC F2, F3 and F4 fractions, respectively.
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Blankenship, Donna A. "Evaluation of SPEC[dot]Microcolumns for the extraction of ranitidine from urine /." This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-09052009-040752/.
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Jakubčeková, Kristína. "Využití různých extrakčních technik pro analýzu výluhů z biouhlu." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2021. http://www.nusl.cz/ntk/nusl-449333.
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Biochar is a material whose properties, composition and impact on the environment are often discussed nowadays. The reason is its application as a soil conditioner. This leads to the need for qualitative as well as quantitative knowledge of its composition. This diploma thesis focuses on the qualitative analysis of biochar leachates processed by various extraction techniques. To approximate the real conditions, six aqueous mediums with different pH values is used, which a solid sample of biochar is exposed to. The prepared leachates are after that processed by extraction techniques, which are solid phase microextraction (SPME), single drop microextraction (HS-SDME), solid phase extraction (SPE) and liquid-liquid extraction (LLE). Analysis of the extracts was performed by gas chromatography-mass spectrometry (GC/MS). The measurements showed that the HS-SDME technique did not show a response. SPE was a rapid technique, but compared to other techniques, it acquired a smaller range of substances. Liquid-liquid extraction, a time-consuming technique, did not obtain as much analytes as SPME. By comparing these applied techniques, the SPME technique is the best choice. The most common determined analytes were those from the group of ketones and carboxylic acids and their derivatives.
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Hill, April Ann. "The development and optimization of techniques for monitoring water quality on-board spacecraft using colorimetric solid-phase extraction (C-SPE)." [Ames, Iowa : Iowa State University], 2007.
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Ude, Mba. "Supercritical fluid extraction of organic species through polymeric systems." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314376.
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Araújo, Matias Monçalves. "Evaluation of the extraction technique SPE GC-(EI) - MS/MS for the analysis of pesticides in irrigated crop of rice water." Universidade Federal de Santa Maria, 2012. http://repositorio.ufsm.br/handle/1/10513.
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Conselho Nacional de Desenvolvimento Científico e TecnológicoIn this study, we performed the synthesis of new symmetrical vinyl sulfides 2-4 by Wittig-Horner reaction of aldehydes derived from diphenyl-, triphenylamine and carbazole with bis[(diphenylphosphinyl)methyl]sulfide 1. The products were obtained in good yields and diastereoselectivities using methodologies well known in our research group. Aiming at the synthesis of photoluminescent compounds, and having vinyl sulfides as precursors, we obtained the vinyl sulfones 5-7 through a simple oxidation step, in good yields and selectively for the E,E isomer. The photophysical properties of vinyl sulfides were interesting, with maximum emission bands observed at blue region of the spectrum, between 411 and 458 nm. Oxidation of sulfide to their respective sulfones, obtaining D-π-A-π-D structures, alters greatly the photoluminescent properties of these compounds. The maximum absorption and emission bands are shifted to the red, due to the processes of intramolecular charge transfer. The strong influence of the solvent polarity suggests the existence of a very polar excited state. The absorptivity coefficients also indicate that the main transitions occur between π-π* electrons, being strongly influenced by the long π-conjugated system existing in these compounds.
Neste trabalho, foi realizada a síntese de novos sulfetos vinílicos simétricos 2-4 através da reação de Wittig-Horner entre aldeídos derivados da difenil-, trifenilamina e do carbazol com o bis[(difenilfosfinoil)metil]sulfeto 1. Os produtos foram obtidos em bons rendimentos e boa diastereosseletividade, utilizando metodologias bastante trabalhadas em nosso grupo de pesquisa. Visando a síntese de composto com propriedades fotoluminescentes, e tendo os sulfetos vinílicos como excelentes precursores, obtiveram-se novas sulfonas vinílicas 5-7 através de fácil etapa de oxidação, sendo as sulfonas obtidas em bons rendimentos e de forma seletiva para o isômero E,E. As propriedades fotofísicas dos sulfetos vinílicos mostraram-se bastante interessantes, com bandas máximas de emissão observadas na região azul do espectro entre 411 e 458 nm. A oxidação dos sulfetos às suas respectivas sulfonas, e obtenção de estruturas do tipo D-π-A-π-D, modifica drasticamente as propriedades fotoluminescentes desses compostos. As bandas máximas de absorção e de emissão são deslocadas para o vermelho devido aos processos de transferência de carga intramolecular, e a forte influência da polaridade do solvente sugere a existência de um estado excitado bastante polar. Os coeficientes de absortividade também indicam que as principais transições ocorrem entre elétrons π-π*, sendo fortemente influenciado pelo longo sistema π-conjugado existente nesses compostos.
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Ehrenbergerová, Martina. "Stanovení reziduí vybraných pesticidních účinných látek ve víně metodou GC/MS." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2010. http://www.nusl.cz/ntk/nusl-216636.
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The grape is one of the oldest cultivated plants. It can be consumed as a fruit or it can be used as a raw material for making stews, juices or the cultivated drink – wine. Generations of wine-makers have been striving to improve both the cultivating conditions of vineyards and the quality of wine. Many harmful elements, such as herbivorous pests, diseases and storms are important factors that can have a negative impact on crop quality. To regulate the effects of these factors, an integrated protection system is used, incorporating agronomical measures, resistant varieties and a wide spectrum of pesticides. However, increasing the usage of pesticides brings certain dangers to both the production quality and the environment. This necessitates the monitoring of the negative effects, including the content of pesticide residues in the grapes. My thesis studies and experimentally assesses selected pesticide residues in certain wine samples.
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Bellu, Edmund. "Detection, analysis, and photocatalytic destruction of the freshwater taint compound geosmin." Thesis, Robert Gordon University, 2007. http://hdl.handle.net/10059/93.
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A significant issue affecting the aquaculture and water industries is the presence of off-flavour compounds in water, which cause problems by imparting an undesirable earthy/musty flavour and smell to water and fish. Two predominant off-flavour compounds are geosmin (GSM) and 2-methylisoborneol (MIB). These compounds are produced by several varieties of cyanobacteria and actinomycetes as metabolic products and can be detected by humans at concentrations as low as 0.015 mg L-1. Removal of GSM and MIB from potable waters has proven to be inefficient using standard water treatment such as filtration, coagulation, flocculation, sedimentation and chlorination. Activated carbon and membrane processes can physically remove GSM and MIB, but do not destroy them, and ozone treatment can be expensive. Titanium dioxide (TiO2) photocatalysis has recently been demonstrated to rapidly degrade GSM and MIB. When the semiconductor catalyst is illuminated with ultraviolet light simultaneous oxidation and reduction reactions occur. Pollutants are broken down into mineral acids, carbon dioxide and water. This study was conducted to determine if TiO2 photocatalysis, using a pelleted form of TiO2 called Hombikat K01/C, was a suitable method for the treatment of potable water. Additionally an analytical method was developed to rapidily analyse the large number of samples generated. Two reactors, a bench scale batch reactor and pilot scale flow reactor, were developed and used to evaluate the efficacy of Hombikat K01/C TiO2 photocatalysis in degrading GSM. The batch reactor, containing Hombikat K01/C, was used to investigate the effect of numerous experimental variables on the photocatalysis of GSM, including initial substrate concentration, pH, light intensity, aeration rate, the presence of additional reactants, and catalysis conducted in deuterated water. GSM was rapidly degraded using the TiO2 batch reactor, with the rate of GSM degradation most affected by light intensity and additional reactants, though pH also had a notable effect. A kinetic isotope effect of 1.61 was observed for the destruction of GSM using Hombikat K01/C TiO2. The flow reactor was also found to efficiently degrade GSM in raw waters. The rate of GSM destruction was found to be significantly lowered by UV shielding of the catalyst, caused by constituents of raw the water used, and the presence of additional reactants. The pilot scale flow reactor was also successfully evaluated in Denmark using gesomin contaminated water from an eel farm
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Carvalho, Ana Rita Martins. "Monitorização de desreguladores endócrinos em águas de rede e águas residuais por SPE-UPLC-ESI-MS/MS. Empresa Portuguesa das Águas Livres (EPAL)." Master's thesis, ISA/UTL, 2012. http://hdl.handle.net/10400.5/5371.
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Engenharia do Ambiente - Instituto Superior de AgronomiaWater is an essential factor in the life and environmental issues and is a current topic of extreme importance to human health. Endocrine disrupters affect the endocrine system, significantly altering the vital functions in living beings. Thus, it is essential to undertake the monitoring of aquatic systems that exposure to and bioaccumulation of these compounds is mitigated. The objective of this study is to monitor the presence of ten EDC in 60 water samples distributed by EPAL and in 24 samples of wastewater from a treatment plant wastewater, using a method of analysis previously implemented in the company's central laboratory. The analysis method used in this work was to Ultra Performance Liquid Chromatography Efficiency associated with tandem mass spectrometry (UPLC-MS/MS) using the extraction technique as solid phase extraction (SPE) and as a method of ionization ionization electrospray (ESI). The compounds under study were estriol, bisphenol A, diethylstilbestrol, estrone, estradiol, ethinyl estradiol, progesterone, octylphenol, nonylphenol and mestranol, having the analytical limits calculated for each compound used in the identification and quantification of the same in water samples under study.
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Madru, Benjamin. "Développement d'un support d'extraction sélective à base d'aptamères : synthèse, caractérisation et application à des matrices complexes." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2010. http://pastel.archives-ouvertes.fr/pastel-00538840.
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L'analyse de composés à l'état de traces dans des échantillons complexes tels que les fluides biologiques, les matrices environnementales ou les denrées alimentaires nécessite une étape de purification avant analyse afin de limiter la présence d'effets de matrice. Les supports conventionnels d'extraction sur phase solide, bien qu'étant très efficaces pour préconcentrer l'échantillon, conduisent souvent à la co-extraction de composés interférents. Afin de pallier ce manque de sélectivité, des supports sélectifs fondés sur des mécanismes de reconnaissance moléculaire ont été développés. Les immunoadsorbants, reposants sur l'utilisation d'anticorps dirigés contre l'analyte et immobilisés sur un support solide, et les polymères à empreintes moléculaires qui possèdent des cavités spécifiques complémentaires d'une molécule empreinte, ont déjà démontré un fort potentiel pour l'extraction sélective de composés de matrices complexes. Un troisième type de support d'extraction sélective également fondé sur un mécanisme de reconnaissance moléculaire exploitant les propriétés des aptamères a été développé lors de cette étude. Les aptamères sont des oligonucléotides capables de fixer de manière spécifique une molécule avec une affinité comparable à celle des anticorps. Un aptamère sélectionné pour reconnaître la cocaïne a été choisi comme aptamère modèle pour cette étude de faisabilité. Différents supports d'immobilisation ont été évalués et les oligoadsorbants obtenus ont été caractérisés en termes de rétention spécifique et non spécifique, de taux de greffage, et de capacité. La sélectivité du support le plus performant en milieu pur a ensuite été évaluée en réalisant l'extraction de la cocaïne de plasma et de sang. L'analyse chromatographique des extraits obtenus a conduit à des chromatogrammes dépourvus de co-élutions, contrairement à ceux issus des traitements généralement employés, démontrant ainsi l'apport en purification de l'oligoextraction. Ce développement a ensuite été transposé avec succès à un autre aptamère, l'aptamère anti-ochratoxine A. L'oligoadsorbant obtenu s'est montré très rétentif, du fait de sa forte affinité, et a permis l'extraction sélective de l'ochratoxine A du vin. Les résultats obtenus sont très similaires à ceux obtenus avec un immunoadsorbant. De plus, les procédures d'extraction s'avèrent beaucoup plus simples à développer que pour les polymères à empreintes moléculaires.
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Porter, Shelley Risch Jr. "Supercritical Fluid Extraction of Nylon 6,6 Fiber Finish and Oligomers." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/35749.
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Quantitation of the amount of finish applied during fiber
manufacturing is an important industrial quality control
process. Finish levels that are too low result in excessive
fiber and mechanical wear. On the other hand, overly high
finish levels may cause residue buildup on the processing
equipment. Removal of the finish has traditionally been
done with solvents such as chloroform or Freon followed by
gravimetric or spectroscopic analysis of the removed
material.
Quantitation of low molecular weight oligomeric
material is another important quality control practice for
the fiber industry in that the presence of these species and
their concentration affect the physical properties of the
polymer. Also, excessively high concentrations of oligomers
may result in residue deposits on processing equipment.
Typical conventional methods for determining the
concentration of oligomers present in fibers involve large
quantities of organic solvent for removal of the oligomers
followed by chromatographic analysis
Increased government regulation of chlorinated and
other solvents has led to investigations of alternate
methods of extraction. Several studies have shown that
supercritical fluid extraction (SFE) using carbon dioxide as
the extraction fluid is an important alternative to
conventional organic solvent extraction for the removal of
both textile finishes and oligomeric material. This
research seeks to extend the previous studies regarding the
application of SFE for the quantitation of finish and
oligomers from nylon 6,6 fibers. The effects of pressure,
extraction temperature, modifier percentage, static
extraction time, and dynamic extraction time on the
supercritical fluid extraction efficiency of nylon 6,6
oligomers were examined. Results from the SFE methods for
both finish and oligomer extractions were compared to
results from conventional solvent extraction. The extracted
oligomers were identified by HPLC with coupled on-line
atmospheric pressure chemical ionization mass spectrometry
(APCI-MS) and HPLC fractionation coupled with off-line
Liquid Secondary Ion Mass Spectrometry (LSIMS).Master of Science
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Stuart, Iain A. "Studies in the application of supercritical fluid extraction to carbamate insecticide residue analysis." Thesis, Glasgow Caledonian University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388284.
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Bergman, Nina. "Sample preparation of 8-hydroxy-2’-deoxyguanosine with solid phase extraction methodology based on molecular imprinting polymers and conventional silica based phases." Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-71325.
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The aim of this study was to develop methods for sample preparation for 8-OHdG in blood plasma samples with different solid phase extraction techniques using HPLC with an elec- trochemical detector. The solid phase extraction cartridges used were Chromabond® C18, Oasis® MAX, and three types of SupelMIPTM cartridges for chloramphenicol, riboflavin, and nitroimidazoles. The SupelMIPTM cartridges are based on molecularly imprinted polymers- technique. The separation of 8-OHdG in samples extracted from blood plasma was carried out with a Thermo Quest Hypersil Division ODS column (250 mm × 4 mm, 3μm I.D.) and methanol:buffer (10:90, v/v) as mobile phase. Recovery and selectivity was studied for the different solid phase extraction methods. The highest recovery was obtained using the Chromabond C18 cartridge with a recovery of 92%, and CV coefficient 9.5% (n = 4). 8-OHdG could not be extracted on MIP-cartridges for chloramphenicol or riboflavin, but was retained on MIP columns for nitroimidazoles, and the highest recovery was 49%.
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Shao, Peimin. "SFE Fractionation and RP-HPLC Characterization of Aquatic Fulvic Acid." Thesis, University of North Texas, 1994. https://digital.library.unt.edu/ark:/67531/metadc500352/.
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The Supercritical Fluid Extraction (SFE) technique was used to fractionate Suwannee River reference fulvic acid (FA). The fractions were characterized by gas chromatography (GC) and reversed-phase high performance liquid chromatography (RP-HPLC). A SFE fractionation method was developed using stepwise gradient of supercritical CO₂ and methanol. Three FA fractions were separated. The average mass recovery was 102% with the coefficient of variation of 2.8%. The fractionation dynamics and the difference in the ratios of UV absorption to fluorescence emission indicate the real fractionation of the FA. The HPLC chromatographic peak patterns and the spectra of the corresponding peaks were almost indistinguishable. The overall results of this research support the argument that FA exhibits polymer-like molecular structure.
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Lefebvre, Thibault. "Production d'extraits non colorés de plantes enrichis en composés bioactifs. Investigation des techniques d’extraction modernes (US, MO, SFE, PLE)." Thesis, Orléans, 2020. http://www.theses.fr/2020ORLE3062.
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Dans le domaine de la cosmétique, de nombreuses matières premières sont utilisées et les extraits naturels issus de plantes en représentent une grande partie. Les extraits végétaux peuvent avoir des activités différentes : antioxydantes, anti-vieillissement.... Cependant, leur couleur essentiellement dû aux pigments peut être un frein à leur utilisation car ils peuvent avoir des problèmes de stabilité. Leur dégradation se traduit par un changement de couleur ce qui peut être incompatible avec leur formulation.L'objectif de la thèse est de trouver des conditions sélectives afin d'extraire des composés d'intérêts sans pigments (principalement chlorophylliens).Dans un premier temps, une étude de la stabilité des chlorophylles a permis d'identifier des conditions d'extraction et de stockage afin d'identifier et de quantifier les chlorophylles natives et leurs produits de dégradation en fonction des différentes approches opératoires. Cela a permis d'identifier des conditions d'extraction et de stockage limitant leurs dégradations. Dans un second temps une modélisation a été réalisée, principalement en chromatographie supercritique, pour déterminer des conditions d'extraction sélective, avec des fluides supercritiques, de molécules antioxydantes (acide carnosique et rosmarinique) d'une part et des pigments chlorophylliens d'autre part à partir de romarin, sans avoir besoin d'effectuer de nombreuses expériences d'extraction. Finalement, une extraction par CO2 supercritique séquencée utilisant des conditions déterminées par le précédent modèle a été développée. Un système extraction/chromatographie en ligne a été développé afin d’appuyer ce développement par des études de cinétiques d'extraction. Cette extraction a permis de réaliser quatre fractions respectivement riches en caroténoïdes, acide carnosique, acide rosmarinique et chlorophyllesIn the field of cosmetics, many raw materials are used and natural extracts from plants represent a large part of them. Plant extracts can have different activities: antioxidants, anti-aging ... However, their color mainly due to pigments can be an obstacle to their use because they can have stability problems. Their degradation results in a change of color which may be incompatible with their formulation.The objective of the thesis is to find selective conditions in order to extract compounds of interest without pigments (mainly chlorophylls).Initially, a study of the stability of chlorophylls allowed identification of extraction and storage conditions in order to identify and quantify native chlorophylls and their degradation products according to the different operating approaches. This made it possible to identify extraction and storage conditions limiting their degradation. Secondly, modeling was carried out, mainly by supercritical chromatography, to determine selective extraction conditions, with supercritical fluids, of antioxidant molecules (carnosic and rosmarinic acids) on the one hand and chlorophyll pigments on the other hand from rosemary, without the need for numerous extraction experiments. Finally, a sequential supercritical CO2 extraction using conditions determined by the previous model was developed. An online extraction/chromatography system was developed to support this development through extraction kinetics studies. This extraction allowed the realization of four fractions respectively rich in carotenoids, carnosic acid, rosmarinic acid and chlorophylls
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Gaylor, Michael O. "Development of Supercritical Fluid Extraction (SFE) for the Determination of Polychlorinated Biphenyls in Tissues of Aquatic Biota." W&M ScholarWorks, 1997. https://scholarworks.wm.edu/etd/1539626103.
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Shahin, Lara. "Analysis of some Chlorinated Pesticides in Jordanian Ground- and Surface Waters by Solid-Phase Extraction and Mass Spectrometric Detection- A Method development." Thesis, Linköping University, Department of Water and Environmental Studies, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2253.
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A solid-phase extraction (SPE) method was developed for the determination of organochlorine pesticides, namely aldrin, alpha-BHC, beta-BHC, delta-BHC, dieldrin, endosulfan I, endosulfan II, endosulfan sulfate, endrin, endrin aldehyde, lindane, heptachlor, heptachlor epoxide, 4,4’-DDD, 4,4’-DDE and 4,4’- DDT in water. The effect of extraction conditions, such as the addition of sodium chloride and methanol to the sample prior to loading was studied. The sample was concentrated by a plain polystyrene-divinylbenzene resin, and the extract was eluted by ethyl acetate. Qualification and quantification of the target pesticides were performedby gas chromatography/ mass spectrometry (GC/MS) in the full-scan and selected ion-monitoring mode, respectively, and for better detection of pesticides in field samples the mass spectrometer was altered from electron ionization (EI) to chemical ionization mode (CI). The repeatability of the method for MilliQ-water fortified with pesticides at a level of 0.1 to 0.6 µg/l ranged from 8 to 18%, and the obtained recoveries ranged from 67 to 135%.
The method was evaluated for the determination of organochlorine pesticides in fourteen surface- and groundwater samples taken from locations along King Talal Dam, King Abdullah Canal and Zarqa River in the Jordan Valley. The limit of detection of the pesticides residues in 500-ml field water samples ranged from 0.0009 to 15.7 ng/l. The obtained results confirmed the presence of trace amounts of some organochlorine pesticides in the analyzed samples, i.e. lindane and endosulfan compounds.
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Silva, Marconiel Neto da. "DESENVOLVIMENTO DE MÉTODO MULTIRESIDUAL PARA ANÁLISE DE PESTICIDAS EM MEL, UTILIZANDO CROMATOGRAFIA A LÍQUÍDO COM DETECTOR ESPECTROFOTOMÉTRICO COM ARRANJO DE DIODOS." Universidade Federal do Maranhão, 2009. http://tedebc.ufma.br:8080/jspui/handle/tede/937.
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Honey is a product of proven therapeutic and nutritional properties, and which may act as an excellent bioindicator, given the way the bees gather and process the raw material used in its preparation. The monitoring of pesticide residues in honey is important both to control product quality in domestic and international markets, and in assessing the potential for contamination in areas near agricultural crops. Considering these facts, we developed a method for analyzing carbamate insecticides (carbaryl and carbofuran), organochlorine (aldrin and dieldrin), organophosphates (dimethoate and parathion methyl) and pyrethroid (permethrin), and the group of anilides herbicide (propanil) and fenoxiácidos (2,4-D) in honey. Hence, in this work the analytical conditions were established for the proper determination of residues of pesticides cited using the technique of solid phase extraction and liquid chromatography with UV detection with a diode array. The study aimed to compare different analytical conditions for the determination of pesticides, looking for better separation, sensitivity, precision and accuracy in the determination of pesticide residues in samples of honey bees. Standard solutions at concentrations ranging from 1.0 to 20.0 μ g mL-1 were evaluated in different mobile phases, using a C18 column (250 x 4.6 mm id, 5 μ m). The mobile phase composition more suitable was acetonitrile: water at pH 3.0 (acidified with acetic acid) in gradient mode, for monitoring the compounds at a wavelength of 220 nm. In the established conditions, except for aldrin and dieldrin and dimeotate, it was observed recoveries between 75.26% and 113.58%, with variation Coefficients Between 2.16% and 11.31% for concentration levels raging from 0:10 to 1.00 μ gg-1 (correlation coefficients between 0.9978 and 0.9998). Recoveries lower than 50% to the cited insecticides were observed when using ethyl acetate solvent extractor and the solvent elution by ethyl acetate, in such a way new studies can be done to obtain better recoveries for these compounds.
O mel é um produto de reconhecidas propriedades nutritivas e terapêuticas e, o qual pode atuar como um excelente bioindicador, dada à forma como as abelhas recolhem e processam a matéria-prima utilizada na sua elaboração. O monitoramento de resíduos de pesticidas no mel é importante, tanto para o controle de qualidade do produto nos mercados nacional e internacional, quanto na avaliação do potencial de contaminação em áreas próximas a cultivos agrícolas. Considerando tais fatos, foi desenvolvido um método para análise dos inseticidas carbamatos (carbaril e carbofurano), organoclorados (aldrin e dieldrin), organofosforados (dimetoato e parationa metílica) e piretróide (permetrina), além do herbicida do grupo das anilidas (propanil) e fenoxiácidos (2,4-D) em mel. Para tanto, neste trabalho foram estabelecidas condições analíticas para a adequada determinação dos resíduos dos citados pesticidas utilizando a técnica de extração em fase solida e cromatografia líquida com detecção espectrofotométrica com arranjo de diodos. O trabalho teve como objetivo comparar diferentes condições analíticas para a determinação dos pesticidas, buscando-se melhor separação, sensibilidade, precisão e exatidão na determinação de resíduos dos pesticidas em amostras de mel de abelhas. Soluções-padrão em concentrações variando de 1,0 a 20,0 μg mL-1 foram avaliadas em diferentes fases móveis, utilizando-se coluna C18 (250 x 4.6 mm d.i., 5 μm). A composição da fase móvel mais adequada foi acetonitrila:água em pH 3,0 (acidificada com ácido acético), em modo gradiente, monitorando-se os compostos em comprimento de onda de 220 nm. Nas condições estabelecidas, excetuando-se aldrin, dieldrin e dimetoato, foram observadas recuperações entre 75,26% a 113,58%, com coeficientes de variação entre 2,16% a 11,31%, para níveis de concentração entre 0,10 a 1,00 μg.g-1 (coeficientes de correlação entre 0,9978 e 0,9998). Recuperações inferiores a 50 % foram, entretanto, observadas para os citados inseticidas, utilizando-se solvente extrator acetato de etila e eluição com acetato de etila, sendo necessários novos estudos para obtenção de melhores recuperações para tais compostos.
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Adorno, Maria Angela Tallarico. "Desenvolvimento de métodos de extração e determinação de bifenilas policloradas por cromatografia gasosa e detector de captura de elétrons em óleo Ascarel, reator anaeróbio e solo." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-27082014-104138/.
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Bifenilas policloradas (PCBs) são componentes de óleo ascarel, usado extensamente (no Brasil até os anos 80) como isolante em transformadores de energia devido às suas propriedades físico-químicas como estabilidade térmica e alta constante dielétrica. Apesar de ter sido proibido em todo o mundo devido à alta toxicidade dos PCBs presentes em sua composição, ainda resta grande quantidade de ascarel em circulação como resíduo \"passivo\" e resultante de contaminação em trocas dos fluidos dos transformadores, além de vazamentos. A principal forma de eliminação é por incineração, que, além de ser um processo caro, pode provocar a formação de compostos mais tóxicos, as dioxinas. Por isso é importante o monitoramento da concentração dessas substâncias, a fim de evitar maiores impactos ambientais na sua disposição, bem como em estudos de biodegradação. Esta matriz é extremamente complexa, o que torna a extração e determinação desses analitos um processo trabalhoso e difícil. Neste trabalho avaliaram-se métodos de extração e determinação de PCBs presentes na solução padrão comercial PCB Congener MIX 1, SUPELCO (PCBs 10, 28, 52, 138, 153 e 180). O desenvolvimento de métodos de extração (cromatografia em coluna, extração líquido-líquido (L-L), extração em fase sólida (SPE) e micro-extração em fase sólida - SPME) dos PCBs foi seguido da determinação, por cromatografia gasosa com detector por captura de elétrons (CG/DCE), em três matrizes diferentes: óleo ascarel, amostras provenientes de reatores anaeróbios em batelada e solo. Os métodos cuja purificação e extração diminuíram o efeito dos interferentes da matriz, como SPE - Sulfoxide, cromatografia em coluna de sílica e extração L-L com n-hexano foram validados pela avaliação dos seguintes parâmetros: linearidade e faixa de aplicação; precisão instrumental; limite de detecção, limite de quantificação e recuperação absoluta. O critério de escolha entre os métodos para extração dos PCBs do óleo que forneceram maior eficiência (cartucho SPE Sulfoxide e coluna de sílica gel, após lavagem ácida; método da adição de padrão, entre 1,0 e 4,0 mg L-1) deve considerar a disponibilidade de recursos, pois a sílica gel é mais viável economicamente do que o cartucho SPE. Os valores de R2 > 0,99 para o método de extração com sílica, mesmo tendo sido considerados apenas três pontos para a curva de calibração, atestam maior linearidade do que o método com SPE Sulfoxide (R2 entre 0,97 e 0,99). A extração L-L e determinação por CG/DCE dos PCBs (padronização interna) de amostras provenientes de reatores anaeróbios em batelada (aquosas, em matriz extremamente complexa com biomassa e espuma de poliuretano para imobilização de microrganismos) foram eficientes na faixa de concentração entre 0,05 e 0,5 mg L-1. Esse método foi adequado para monitorar PCBs em estudo de degradação anaeróbia e teste de adsorção dos PCBs em espuma; forneceu linearidade com R2 entre 0,93 e 0,96 e limites de detecção de 0,048 a 0,298 mg L-1, além de recuperação absoluta entre 14,1% e 110,7%. As condições testadas por SPME não permitiram a extração dos PCBs de óleo e de solo, principalmente devido à dessorção incompleta dos PCBs da fibra de polidimetil-siloxano, de 100 μm.Polychlorinated biphenyls (PCBs) are components of ascarel, oil widely used as insulation (until the \'80s in Brazil) due to its physicochemical properties such as thermal stability and high dielectric constant. Despite having been banned worldwide due to the high toxicity of PCBs present in its composition, there are still lots of outstanding ascarel as \"passive\" residue and resulting contamination of fluids in transformers exchanges, plus leaks. The main form of disposal is incineration, which, besides being costly, can cause the formation of more toxic compounds, that is, dioxins. It is therefore important to monitor the concentration of these substances in order to prevent further environmental impacts in their disposal, as well as in studies of biodegradation. This is an extremely complex matrix, which makes the extraction and determination of this analytes very difficult and labor intensive. In this work we have evaluated methods of extraction and determination of the PCBs present in the standard solution Congener MIX 1, SUPELCO (PCBs 10, 28, 52, 138, 153 e 180). The extraction and cleanup developed methods which reduced the effects of interfering matrix as solid phase extraction (SPE) - Sulfoxide, column chromatography on silica and liquid-liquid (L-L) extraction with n-hexane, and solid phase microextraction (SPME) after determination of the PCBs by gas chromatography with electron capture detector (GC/ECD) were validated by assessing the following parameters: linearity and range of application; instrumental precision; detection limit; limit of quantification and absolute recovery. The criterion for choosing between the methods for extraction of PCBs from the oil with a higher efficiency (SPE cartridge Sulfoxide and silica gel column, after acid washing; using the standard addition method, between 1.0 and 4.0 mg L-1) must evaluate the availability resources, since the silica gel is more economically viable than the SPE cartridge. The R2 values > 0.99 for silica extraction method, even though it was considered only three points for the calibration curve, attested higher linearity than the method with SPE Sulfoxide (R2 between 0.97 and 0.99). The L-L extraction and determination by GC/ECD of the PCBs (internal standardization) of samples from batch anaerobic reactors (aqueous, in a very complex matrix with biomass and polyurethane foam for the immobilization of microorganisms) were efficient in the concentration range between 0.05 and 0.5 mg L-1. This method was suitable to monitor PCBs in anaerobic degradation studies and its adsorption on foam; provided R2 linearity between 0.93 and 0.96 and detection limits from 0.048 to 0.298 mg L-1, as well as absolute recovery between 14.1% and 110.7%. The conditions tested for SPME technique did not allow the extraction of the PCBs from the oil and soil, mainly due to the \"incomplete dessorption\" of PCBs from the polydimethylsiloxane fiber of 100 micron.
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Claude, Bérengère. "Intérêt des polymères à empreintes moléculaires pour la préparation d'échantillons par extraction solide-liquide. Applications aux triterpènes dans les plantes et aux dopants dans les urines." Phd thesis, Université d'Orléans, 2007. http://tel.archives-ouvertes.fr/tel-00148669.
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Ce mémoire reporte les études menées sur des polymères à empreintes moléculaires (MIP) en extraction solide-liquide (SPE). L'influence de différents facteurs (nature des interactions polymère-analyte, composition de la matrice de l'échantillon, polarité des solvants d'extraction) sur la sélectivité et la capacité des MIPs est étudiée. La première application révèle l'influence des liaisons hydrogène lors de l'extraction d'un échantillon organique sur un MIP préparé à partir d'acide méthacrylique (MAA). Des expériences de réactivité croisée réalisées sur des molécules analogues à la molécule empreinte (triterpène) montrent l'impact de la nature et de la position des groupes fonctionnels sur la spécificité de reconnaissance des analytes par le MIP. La capacité d'une cartouche SPE est évaluée à partir d'une solution standard puis d'un extrait végétal avec des solvants de lavage adaptés à la matrice.
Les interactions polymère-analyte sont ensuite étudiées dans une matrice aqueuse saline. Deux MIPs respectivement préparés à partir de MAA et de MAA-styrène, avec le clomiphène comme molécule empreinte, sont caractérisés par les isothermes de Freundlich puis appliqués à la préconcentration du tamoxifène, molécule hydrophobe et basique contenue dans des urines hydrolysées et dopées. Les liaisons hydrogène, ioniques et hydrophobes intervenant dans la rétention des analytes sont étudiées par des équilibres d'adsorption et par SPE. La percolation de l'urine sur un support hydrophobe en préalable de la SPE-MIP, ou directement sur un MIP à caractère hydrophobe renforcé (MAA-styrène) entraîne une augmentation des rendements d'extraction avec un nombre d'étapes de lavage réduit.
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Van, Wyk BJ, Wyk MA Van, and den Bergh F. Van. "A note on difference spectra for fast extraction of global image information." SAIEE Africa Research Journal, 2007. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1001081.
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The concept of an Image Difference Spectrum, a novel tool for the extraction of global
image information, is introduced. It is shown that Image Difference Spectra are fast alternatives to
granulometric curves, also referred to as pattern spectra. Image Difference Spectra are
computationally easy to implement and are suitable for real-time applications.
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Tollbäck, Johanna. "New methods for determination of airborne pollutants : Focus on tetrabromobisphenol A, organophosphate triesters and polycyclic aromatic hydrocarbons." Doctoral thesis, Stockholms universitet, Institutionen för analytisk kemi, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-26700.
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The work presented in this thesis concerns the development and evaluation of new methods of sampling and analysis of organic pollutants in the indoor and outdoor environment. In Paper I, the development of a new method was reported for the determination of the brominated flame retardant tetrabromobisphenol A (TBBPA) in air using sampling with glass fiber filter and polyurethane foam (PUF), ultrasonic solvent extraction and liquid chromatography coupled to electrospray ionisation mass spectrometry (LC-ESI/MS). The MS fragmentation mechanism of TBBPA was thoroughly investigated and different acquisition modes were evaluated to achieve the most sensitive and selective detection. In Papers II and III, the potential use of Empore SPE membranes was evaluated for air sampling of volatile, semi-volatile and particle-associated organic compounds. Breakthrough studies conducted for 24h at air flows of 10- 20 L/min showed that the SPE membranes efficiently retains volatile and semi-volatile organophosphate esters and particles >10 nm. Effort was invested in the development of fast and environmental friendly methods, with low cost, for sample clean up and analysis. In Paper II, the sample preparation technique was dynamic solvent extraction with methanol coupled to LC-ESI/MS. The total run time per sample, including both extraction and separation, was less than 34 min, consuming only 1.6mL methanol. In Paper III, efficiency of selective extraction of polycyclic aromatic hydrocarbons from particulate matter sampled with Empore SPE membranes, using dynamic subcritical water extraction (DSWE) was investigated. Acceptable recoveries of the investigated compounds from reference material (SRM 1649a) were achieved. In Paper IV, the application of dynamic solid phase micro-extraction (SPME) air sampling was evaluated using, gas chromatography/positive ion chemical ionisation (GC/PICI) and tandem-MS detection for the determination of organophosphate esters in work environment.
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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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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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Amini, Nahid. "Novel Solid Phase Extraction and Mass Spectrometry Approaches to Multicomponent Analyses in Complex Matrices." Doctoral thesis, Stockholms universitet, Institutionen för analytisk kemi, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-38625.
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Analysis of compounds present in complex matrices is always a challenge, which can be partly overcome by applying various sample preparation techniques prior to detection. Ideally, the extraction techniques should be as selective as possible, to minimize the concentration of interfering substances. In addition, results can be improved by efficient chromatographic separation of the sample components. The elimination of interfering substances is especially important when utilizing mass spectrometry (MS) as a detection technique since they influence the ionization yields. It is also important to optimize ionization methods in order to minimize detection limits. In the work this thesis is based upon, selective solid phase extraction (SPE) materials, a restricted access material (RAM) and graphitized carbon black (GCB) were employed for clean up and/or pre-concentration of analytes in plasma, urine and agricultural drainage water prior to liquid chromatography/mass spectrometry (LC/MS). Two SPE formats, in which GCB was incorporated in µ-traps and disks, were developed for cleaning up small and large volume samples, respectively. In addition, techniques based on use of sub-2 µm C18 particles at elevated temperatures and a linear ion trap (LIT) mass spectrometer were developed to improve the efficiency of LC separation and sensitivity of detection of 6-formylindolo[3,2-b]carbazole (FICZ) metabolites in human urine. It was also found that GCB can serve not only as a SPE sorbent, but also as a valuable surface for surface-assisted laser desorption ionization (SALDI) of small molecules. The dual functionality of GCB was utilized in a combined screening-identification/quantification procedure for fast elimination of negative samples. This may be particularly useful when processing large numbers of samples. SALDI analyses of small molecules was further investigated and improved by employing two kinds of new surfaces: oxidized GCB nanoparticles and silicon nitride.
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Kosárová, Hedvika. "Aplikace prekoncentračních/separačních technik pro stanovení platiny v životním prostředí atomovou spektrometrií." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2013. http://www.nusl.cz/ntk/nusl-216914.
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This thesis deals with optimization of conditions for the determination of platinum by electrothermal atomic absorption spectrometry. The theoretical part describes the occurrence of platinum in different part of the environment, its physical and chemical properties, transport and bioavailability. There is also evaluated appropriate method for determination and preconcentration of platinum. The experimental part describes advance of optimize the measurement conditions for ETA-AAS, further is describes optimization of condition for SPE and work with real samples on which are applied this conditions.
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Bratkowska, Dominika. "Development and application of new polymeric materials for sorptive extraction techniques." Doctoral thesis, Universitat Rovira i Virgili, 2011. http://hdl.handle.net/10803/63173.
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El desenvolupament de diferents materials per a les tècniques d’extracció mitjançant processos de sorció és una àrea en continua expansió; no obstant, l’extracció d’anàlits polars encara és un tema que requereix més investigació. En aquesta Tesi s’han desenvolupa nous materials que reuneixen de selectivitat i/o capacitat característiques per a extreure contaminants orgànics polars en mostres aquoses. La primera part descriu el desenvolupament de nous materials polimèrics que milloren la capacitat i selectivitat de l’extracció en fase solida, i hi inclau els polímers altament entrecreuats amb caràcter hidrofílic, els sorbents altament entrecreuats d’intercanvi iònic de mode-mixte i els líquids iònics suportots en fases polimèriques; així com la seva avaluació com a nous sorbents per a la extracció de contaminats polars en diferents mostres aquoses mediambientals seguit de l’anàlisi per LC. La segona part está centrada en la preparació de noves barres agitadores amb recobriments monolítics polars i la seva posterior aplicació per l’extracció d’analits polars en diferents aigües de procedéncia mediambiental.The development of different materials for sorptive extraction techniques is a continuously evolving field of research. Although there have been significant developments in this area, the extraction of polar analytes is still considered the bottleneck of the extraction process. The efforts have been undertaken to improve capacity and selectivity. For this reason, one of the main objectives of this Thesis is to develop new materials to extract polar organic contaminants from water samples. The first part reports on the development of new polymeric materials for solid-phase extraction including hypercrosslinked polymers with hydrophilic character, mixed-mode ion-exchange hypercrosslinked sorbents and supported ionic liquid polymeric phases and their evaluation as SPE sorbents for the extraction of polar contaminants, followed by LC analysis. The second part is focused on the preparation of new stir bars with polar monolithic coatings and their application to stir bar sorptive extract polar analytes from environmental water samples.
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Shihomatsu, Helena Miho. "Desenvolvimento e validação da metodologia SPE-LC-MS/MS para a determinação de fármacos e droga de abuso nas águas da represa Guarapiranga - São Paulo/SP, Brasil." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-28042015-095207/.
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Este estudo apresenta o desenvolvimento da metodologia de extração em fase sólida e separação em cromatográfica líquida acoplada a espectrometria de massas em sequencia, SPE-LC-MS/MS, para a determinação de 21 (vinte e um) fármacos pertencentes a diferentes classes terapeuticas, 1 (uma) droga de abuso e seu principal metabólito, em amostras de água superficial. A separação cromatográfica foi otimizada estudando o desempenho de fases estacionárias e fases móvies. A quantificação dos compostos selecionados foi realizada com a ionização por eletronebulização (electrospray ionization- ESI) e o espectrômetro de massas operando no modo de Monitoramento de Múltiplas Reações (Multiplas Reaction Monitoring- MRM). A validação da metodologia proposta foi realizada utilizando os parâmetros de seletividade, efeito de matriz, faixa de trabalho, linearidade, limites de detecção (LD) e quantificação (LQ), precisão, exatidão, recuperação e robustez. A validação da metodologia permitiu a sua aplicação na avaliação da distribuição dos 23 compostos selecionados, nas águas da represa Guarapiranga, um dos principais sistemas produtor de água potável da Região Metropolitana de São Paulo (RMSP). A presença desses poluentes nos ambientes aquáticos é proveniente da liberação direta do esgoto urbano das habitações do seu entorno, como consequência do precário sistema de saneamento básico. As águas da represa Guarapiranga foram avaliadas em 14 (quatorze) locais estrategicamente escolhidos e amostradas durante 3 (três) campanhas de coleta de amostra (agosto de 2011, setembro de 2012 e abril de 2013). Nessas amostras foram quantificados acetaminofeno (9,6 - 254 ng L-1), atenolol (8,5 177 ng L-1), benzoilegonina (7,9 139 ng L-1), cafeína (27 27386 ng L-1), carbamazepina (12 358 ng L-1), clortalidona (9,4 35 ng L-1), cocaína (12,8 2650 ng L-1), diclofenaco (8 35 ng L-1), enalapril (20 ng L-1), losartana (6,7 114 ng L-1) e valsartana (9,7 - 47 ng L-1). O ponto de coleta denominado de GU103-12 (23°4188.5S 46°4467.3W) foi a região que apresentou os valores mais elevados quanto ao nível de concentração dos compostos avaliados e ao índice de risco integrado de poluição química aquática (Integrated Risk Index of Chemical Aquatic Pollution IRICAP). O estudo também foi realizado em amostras de água de reservatórios das Unidades de Gerenciamento de Recursos Hídricos (UGRHI) 5 e 6 do Estado de São Paulo. Os resultados demonstraram que o uso e a ocupação do solo influenciam diretamente na qualidade da água dos reservatórios, evidenciando a necessidade de implementar melhorias no sistema de coleta de esgoto e de ocupação irregular para evitar a contaminação e o descarte inadequado em ambientes aquáticos.This study presents the development of the methodology of solid phase extraction and liquid chromatography - tandem mass spectrometry, SPE-LC-MS/MS, for the determination of 21 (twenty one) pharmaceuticals belonging to different therapeutic groups, 1 (one) illicit drug and its major metabolite, in surface water samples. The chromatographic separation was optimized by studying the performance of different stationary and mobile phases. Quantitation of selected compounds was performed by electrospray ionization (ESI) and the mass spectrometer operating in a multiple reaction monitoring (MRM) mode. The validation of the proposed methodology was performed using the parameters of selectivity, matrix effect, dynamic range, linearity, limit of detection (LOD), limit of quantification (LOQ), precision, accuracy, recovery and robustness. The validation of methodology allowed to apply the methodology in the evaluation of the distribution of the 23 (twenty one) selected compounds, in Guarapiranga Dam waters, an of the major producer system of drinking water of the Metropolitan Region of São Paulo (MRSP). The presence of these pollutants in aquatic environments is from the direct release of urban sewage from the homes of your surroundings, as a result of poor sanitation system. The waters of Guarapiranga dam were evaluated in 14 (fourteen) locations strategically chosen and sampled in 3 (three) campaigns of sample collection (August 2011, September 2012 and April 2013). In these samples were quantified acetaminophen (9.6 - 254 ng L-1), atenolol (8.5 - 177 ng L-1), benzoylegonine (7.9 - 139 ng L-1), caffeine (27 - 27386 ng L-1) carbamazepine (12 - 358 ng L-1), chlorthalidone (9.4 - 35 ng L-1), cocaine (12.8 - 2560 ng L-1), diclofenac (8 - 36 ng L-1), enalapril (20 ng L-1), losartan (6.7 - 114 ng L-1) and valsartan (9.7 - 47 ng L-1). The sample siting GU103-12 (23°4188.5S 46°4467.3W) was the region with the highest values in the level of concentration of the target compounds and the integrated risk index of chemical aquatic pollution (IRICAP). The study was also conducted on water samples from reservoirs of the UGRHI (Unit of Water Resources Management) 5 and 6, State o São Paulo. The results showed that the use and occupation of land directly influence the reservoir water quality highlighting the need to implement improvements in sewage collection system and illegal occupation to prevent contamination and the improper disposal in aquatic environments.
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Schnur, Steven R. "Identification and classification of OFDM based signals using preamble correlation and cyclostationary feature extraction." Thesis, Monterey, California : Naval Postgraduate School, 2009. http://edocs.nps.edu/npspubs/scholarly/theses/2009/Sep/09Sep%5FSchnur.pdf.
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Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, September 2009.Thesis Advisor(s): Tummala, Murali ; McEachen, John. "September 2009." Description based on title screen as viewed on November 5, 2009. Author(s) subject terms: IEEE 802.11, IEEE 802.16, OFDM, Cyclostationary Feature Extraction, FFT Accumulation Method. Includes bibliographical references (p. 103-104). Also available in print.
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Burman, Lina. "Chromatography and extraction techniques for new evaluation methods of polyolefins long-term performance." Doctoral thesis, Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-219.
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Tredoux, A. G. J. "Stir bar sorptive extraction for the analysis of beverages and foodstuffs." Thesis, Stellenbosch : University of Stellenbosch, 2008. http://hdl.handle.net/10019.1/1316.
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Thesis (PhD (Chemistry and Polymer Science))--University of Stellenbosch, 2008.The main goal of this study was the development of new technologies based on modern analytical techniques for analysis of volatiles in wines. Due to the exponential growth of the wine industry and consumer demands for an enjoyable, safe-to-consume, and high quality product, the need for arose for methodologies aiding the understanding of wine better arose. Chemical analysis is a valuable way of studying the composition of wine in depth. Very sophisticated instrumentation is available nowadays but almost always the sample needs to be cleaned up or concentrated before such analysis. This study investigates the use of stir bar sorptive extraction (SBSE) as such a technique. It is shown that SBSE combined with gas chromatography-mass spectrometry (GC-MS) is extremely suited for a wide number of analyses and during the course of the study the technique was applied for troublesome analytical challenges in various beverages and foodstuffs. The study focuses on the development of a screening technique for volatiles in wine using SBSE and the application of the data to various chemometrical techniques for classification purposes. A second part of the study shows the applicability of SBSE for extraction of pesticides, contaminants and preservatives from wine, water, lemon flavoured beverages and yoghurt. The method is also elaborated upon by development of faster analysis methods for wine and beer and the investigation of using SBSE for headspace sampling of wine. In all the applications, SBSE technology was shown to be sensitive, repeatable, robust and very simple to use.
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Blažková, Eva. "Stanovení perfluorovaných sloučenin pomocí separačních metod." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2010. http://www.nusl.cz/ntk/nusl-216600.
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The theoretical part of this diploma thesis consists of current matters regarding the presence of perfluorinated organic compounds in living environment elements. The attention has been focused on perfluoroktanoic acid (PFOA), (PFOS), and (FOSA). Physical-chemical characteristics of these organic pollutants and their toxicological and environmental aspects have been described. Possible ways of the pollutants analytical determination have been specified. The experimental part has explored effects of extraction techniques (sonication, pressurized solvent extraction, solid-phase extraction) used for PFAS separation from seats of fire soil sample. Identification of the analytes have been achieved by liquid chromatography/mass spektrometry.
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Sedláček, Jaroslav. "Stanovení nonylfenolu a jeho izomerů ve vodách." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2013. http://www.nusl.cz/ntk/nusl-216949.
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This diploma thesis is focused on the issue of nonylphenol, degradation product of surfactants. Nonylphenol however most often arises in wastewater treatment plants predominantly during the microbial degradation of nonylphenol ethoxylates used in industry. It is a substance highly bioaccumulative, toxic predominantly to aquatic organisms. Furthermore, it belongs among hormone disruptors. The detailed research was prepared, on the basis which experimental part of diploma thesis was solved. Nonylphenol was determined in samples of the wastewater. The solid phase extraction (SPE) was used for the isolation of the analyte and purification of the extract. The final determination was performed on the gas chromatography with tandem mass spectrometry with time of flight analyzer (TOF). All steps of the preanalytical and the analytical procedure were optimized.
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Benešová, Markéta. "Stanovení léčiv pomocí HPLC s různými typy detektorů." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2011. http://www.nusl.cz/ntk/nusl-216704.
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This diploma thesis deals with the determination of macrolide antibiotics in wastewater, especially with erythromycin, clarithromycin and roxithromycin. In this time are these pharmaceuticals prescribed quite frequently. Solid phase extraction (SPE) was used for the isolation and the purification of selected analytes from an aqueous matrix; as the suitable procedure was found the using Oasis HLB cartridges. High performance liquid chromatography with mass spectrometry detection (HPLC-MS) was optimized for its analysis of selected pharmaceuticals. The optimized method was used for the determination of pharmaceuticals in real water samples, which was taken at the inflow and the outflow of the urban wastewater treatment plant in Brno-Modřice.
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Brown, Jenelle Daria. "Development of a method for the simultaneous detection of mycotoxins in corn using supercritical fluid extraction (SFE), high performance liquid chromatography (HPLC), and electrospray-atmospheric pressure ionization/mass spectrometry (ES-API/MS) for extraction, separation, and identification." Thesis, University of Iowa, 1999. https://ir.uiowa.edu/etd/2802.
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Faria, Leonardo Jardim da Silva. "Avaliação de diferentes sorventes na extração em fase solida de pesticidas em agua : desenvolvimento e validação de metodologia." [s.n.], 2004. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250506.
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Orientador: Isabel Cristina Sales Fontes JardimDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica
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