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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Avaliação de técnicas miniaturizadas de preparação de amostras na análise enantiosseletiva de fármacos quirais com diferentes características ácido-base em meio microssomal e aplicação em estudos de metabolismo in vitro / Evaluation of microextraction techniques for sample preparation for the enantioselective analysis of chiral drugs with different acid-base characteristics in microsomal medium and application to in vitro metabolism studies

Rodrigo Almeida Simões 04 April 2012 (has links)
Neste trabalho, a microextração em fase líquida com membrana cilíndrica oca (HF-LPME), a microextração líquido-líquido dispersiva (DLLME) e a microextração em fase sólida na configuração de um filme delgado (SPME/TFME) foram empregadas como técnicas de microextração para a preparação de amostras microssomais no estudo de metabolismo in vitro de fármacos quirais com diferentes características ácido-base. Para análise empregou-se a cromatografia líquida de alta eficiência (HPLC) com detector por absorção no UV e a cromatografia líquida acoplada à espectrometria de massas (LC-MS-MS). O fármaco neutro isradipina (ISR) foi o primeiro a ser abordado. Um método estereosseletivo empregando HFLPME- HPLC foi desenvolvido para a determinação dos enantiômeros da ISR e seu principal metabólito (um derivado piridínico da isradipina - PDI) em fração microssomal isolada de fígado de ratos. Os analitos foram extraídos de 1 mL de meio microssomal utilizando o procedimento HF-LPME na configuração duas fases, tendo o solvente acetato de hexila como fase aceptora. Pela primeira vez, o PDI e os enantiômeros da ISR foram resolvidos numa mesma corrida cromatográfica. Para esta separação foi utilizada uma coluna Chiralpak AD® e hexano:2-propanol:etanol (94/04/02, v/v/v) como fase móvel, na vazão de 1,5 mL min-1. A ISR e o PDI foram detectados em 325 nm e o padrão interno, oxibutinina, foi detectado em 225 nm. A validação do método mostrou valores de recuperação de 23% para o PDI e 19% para cada enantiômero da ISR, 50 ng mL-1 como limite de quantificação (LOQ) para todos os analitos e linearidade entre 50-5000 ng mL-1 e 50-2500 ng mL-1 para o PDI e cada enantiômero da ISR, respectivamente. O método desenvolvido e validado foi aplicado em um estudo de metabolismo in vitro, utilizando microssomas hepáticos de ratos, mostrando que o (+)-(S)-ISR foi preferencialmente metabolizado. Do mesmo modo que para a ISR, um método analítico empregando HF-LPME-HPLC no modo três-fases foi desenvolvido para a análise estereosseletiva concomitante do bufuralol (BF) e dos seus principais metabólitos 1\'- oxobufuralol (1\'-Oxo-BF) e 1\'-hidroxibufuralol (1\'-OH-BF) em preparações microssomais. As análises por HPLC foram conduzidas empregando uma coluna Chiralcel OD-H® com fase móvel composta por hexano:2-propanol:metanol:dietilamina (97,5/2,0/0,5/0,5, v/v/v/v), na vazão de 1,5 mL min-1 e detecção em 248 nm e 273 nm. As condições otimizadas da HFLPME foram: n-octanol como solvente orgânico, ácido acético 0,2 mol L-1 como fase aceptora, fase doadora com pH ajustado em 13 e agitação de 1500 rpm por 30 min. O método foi validado e apresentou valores de recuperação entre 63 - 69% para os analitos e mostrou-se linear entre 100 - 5000 ng mL-1 para cada enantiômero do 1\'-Oxo-BF e 100 - 2500 ng mL-1 para cada estereoisômero do 1\'-OH-BF (r > 0,99), com LOQ de 100 ng mL-1 para todos os analitos. O método desenvolvido e validado foi aplicado em um estudo de metabolismo in vitro do BF utilizando microssomas hepáticos de ratos, que mostrou formação predominante do (S)-1\'-Oxo-BF e do (R,R)-1\'-OH-BF. Um segundo fármaco básico abordado neste trabalho foi a ranolazina (RNZ). Para a análise enantiosseletiva da RNZ e de um de seus metabólitos (desmetil ranolazina - DRNZ) em fração microssomal isolada de fígado de ratos, foi desenvolvido um método estereosseletivo empregando a DLLME-LC-MS-MS. Os analitos foram extraídos de 0,5 mL de meio microssomal utilizando o procedimento DLLME, tendo o clorofórmio como solvente extrator e acetona como solvente dispersante. Pela primeira vez os enantiômeros da RNZ e DRNZ foram resolvidos numa mesma corrida cromatográfica. ii Para esta separação foi utilizada uma coluna Chiralcel OD-H® e hexano:etanol (60/40, v/v) e 0,05% de dietilamina como fase móvel, na vazão de 1,0 mL min-1. A validação do método mostrou valores de recuperação em torno dos 55 e 45% para os enantiômeros da RNZ e DRNZ, respectivamente. Os LOQ foram de 25 ng mL-1 para cada enantiômero da RNZ e 10 ng mL-1 para cada enantiômero da DRNZ. A linearidade foi estabelecida entre 10-1000 ng mL-1 e 25-2500 ng mL-1 para cada enantiômero da DRNZ e RNZ, respectivamente. O método desenvolvido e validado foi aplicado em um estudo de metabolismo in vitro utilizando microssomas hepáticos de ratos, mostrando que a metabolismo da RNZ foi enantiosseletivo. Finalmente, um método analítico empregando a SPME/TFME-LC-MS-MS foi desenvolvido para a análise simultânea do fármaco anfótero repaglinida (RPG) e dois dos seus principais metabólitos, a 2-despiperiril-2-amino-repaglinida (DA-RPG) e a 2-despiperidil-2-(5- carboxipentilamina)-repaglinida (DC-RPG) em fração microssomal isolada de fígado humano. A SPME/TFME foi conduzida com o auxílio do equipamento Multi Sampler SPME nas seguintes condições: pré-condicionamento dos blades com 1 mL de uma solução metanol:água (50/50, v/v) por 30 min, 60 min de extração e 90 min de dessorção com 1 mL de fase móvel. A análise por LC-MS-MS foi feita empregando uma coluna cromatográfica C18 em modo reverso, com fase móvel composta por acetonitrila:água (50/50, v/v) e 0,1% de ácido acético, na vazão de 0,5 mL min-1. A validação do método mostrou valores de recuperação acima dos 80% para todos os analitos. O LOQ foi de 2 ng mL-1 para todos os analitos, sendo o método linear no intervalo 2-1000 ng mL-1 para a RPG e 2-500 ng mL-1 para a DA-RPG e DC-RPG. Os analitos foram estáveis durante todo o protocolo analítico e de metabolismo. O método validado foi aplicado em um estudo de metabolismo in vitro utilizando microssomas hepáticos de humanos, mostrando que o perfil metabólico da RPG e a taxa de formação da DA-RPG e DC-RPG é alterada em função da concentração de proteínas microssomais no meio de incubação e também em função do tempo de incubação. Além disso, os resultados mostrama possibilidade de haver diversos outros metabólitos que não foram monitorados. / In the present work, the microextraction techniques hollow-fiber liquid phase microextraction (HF-LPME), dispersive liquid-liquid microextraction (DLLME) and solid phase microextraction based on thin film (SPME/TFME) were used as sample preparation techniques to study the in vitro metabolism of chiral drugs with distinct acid-base characteristics. High-performance liquid chromatography (HPLC) with UV detection and liquid chromatography coupled to mass spectrometry (LC-MS-MS) were used for the analyses. An enantioselective liquid chromatographic method using two-phase hollow- fiber liquid-phase microextraction (HF-LPME-HPLC) was developed for the determination of isradipine (ISR) enantiomers and its main metabolite (pyridine derivative of isradipine - PDI) in microsomal fraction isolated from rat liver. The analytes were extracted from 1 mL of microsomal medium using a two-phase HF-LPME procedure with hexyl acetate as the acceptor phase, 30 min of extraction and sample agitation at 1500 rpm. For the first time, ISR enantiomers and PDI were resolved. For this separation, a Chiralpak AD® column with hexane:2-propanol:ethanol (94/04/02, v/v/v) as mobile phase at a flow rate of 1.5 mL min-1 were used. The column was kept at 23 °C ± 2. The drug and metabolite detection was performed at 325 nm and the internal standard oxybutynin was detected at 225 nm. The recovery rates were 23% for PDI and 19% for each ISR enantiomer. The method presented quantification limits (LOQ) of 50 ng mL-1 and it was linear over the concentration range of 50-5000 ng mL-1 and 50-2500 ng mL-1 for PDI and each ISR enantiomer, respectively. The validated method was employed to an in vitro metabolism study of ISR using rat liver microsomal fraction, showing that (+)-(S)-ISR is preferentially metabolized. In the same way, a three-phase HF-LPME-HPLC method for the stereoselective determination of bufuralol metabolites, 1\'-oxobufuralol (1\'-Oxo-BF) and 1\'-hydroxybufuralol (1\'-OH-BF), in microsomal preparations is described for the first time. The HPLC analysis was carried out using a Chiralcel OD-H® column with hexane:2-propanol:methanol (97.5/2.0/0.5, v/v/v) plus 0.5% diethylamine as the mobile phase, and UV detection at 248 and 273 nm. The HF-LPME optimized conditions involved: n-octanol as the organic solvent, 0.2 mol L-1 acetic acid as the acceptor phase, donor phase pH adjusted to 13, sample agitation at 1500 rpm and extraction for 30 min. By using this extraction procedure, the recovery rates were in the range of 63- 69%. The method was linear over the concentration range of 100-5000 ng mL-1 for each enantiomer of 1\'-Oxo-BF and of 100-2500 ng mL-1 for each stereoisomer of 1\'-OH-BF. The quantification limits were 100 ng mL-1 for all analytes. The validated method was used to assess the in vitro metabolism of bufuralol using rat liver microsomal fraction that demonstrated predominant formation of (S)-1\'-Oxo-BF and (R,R)-1\'-OH-BF. A second basic drug addressed in this thesis is ranolazine (RNZ). For the chiral analysis of RNZ and one of its metabolites (desmethyl ranolazine - DRNZ) in microsomal fraction isolated from rat liver, an analytical enantioselective method using DLLME-LC-MS-MS was developed. The analytes were extracted from 0.5 mL of microsomal medium by DLLME. Chloroform was the extractor solvent and acetone the dispersive solvent. The enantiomers of RNZ and DRNZ were analyzed simultaneously for the first time using a Chiralcel OD-H® column and hexane:ethanol (60/40, v/v) plus 0.05% diethylamine as mobile phase at a flow rate of 1.0 mL min-1. Method validation showed recoveries in the order of 55 and 45% for the enantiomers iv of RNZ and DRNZ, respectively. The LOQs were 25 ng mL-1 for each RNZ enantiomers and 10 ng mL-1 for each DRNZ enantiomers. Linearity was established between 10-1000 ng mL-1 and 25-2500 ng mL-1 for each DRNZ and RNZ enantiomers, respectively. The validated method was employed to an in vitro metabolism study of RNZ using rat liver microsomal fraction, showing that the metabolism of RNZ is enantioselective. Finally, an analytical method was developed employing SPME/TFME-LC-MS-MS for the simultaneous analyses of the anphoteric drug repaglinide (RPG) and two of the its main metabolites 2-despiperidyl- 2-amino repaglinide (DA-RPG) and 2-despiperidyl-2-(5-carboxypentylamine) repaglinide (DC-RPG) in human microsomal fraction. The SPME/TFME procedure was carried out with the support of \"Multi Sampler SPME\" under the following conditions: conditioning of the blades with 1 mL of methanol:water (50/50, v/v) for 30 min, 60 min for extraction and 90 min for desorption with 1 mL of mobile phase. The LC-MS-MS analyses were performed using a C18 column under reversed phase conditions, with the mobile phase of acetonitrile:water (50/50, v/v) plus 0.1% acetic acid at a flow rate of 0.5 mL min-1. The method validation showed recoveries over 80% for all analytes. The LOQ was 2 ng mL-1 for all analytes, and the method was linear over the concentration range of 2 e 1000 ng mL-1 for RPG and of 2 a 500 ng mL-1 for DA-RPG and DC-RPG. The validated method was used to assess the in vitro metabolism profile of RPG by using human liver microsomes. These studies showed that the rate of formation of DA-RPG and DC-RPG depends on both microsomal protein concentration in the incubation medium and the incubation time. Furthermore, the results highlighted the possibility of formation of several other metabolites which have not been monitored.
92

Microextração em fase sólida e cromatografia gasosa convencional e bidimensional para classificação de méis / Solid phase microextraction and conventional and comprehensive gas chromatography for the classification of honeys

Marques, Sandra Regina Rivellino, 1975- 19 August 2018 (has links)
Orientador: Fabio Augusto / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-19T18:08:24Z (GMT). No. of bitstreams: 1 Marques_SandraReginaRivellino_D.pdf: 2317302 bytes, checksum: fe68941a7328088e8aaba96b46928a24 (MD5) Previous issue date: 2011 / Resumo: A técnica de microextração em fase sólida através do headspace (HS-SPME) combinada com a cromatografia gasosa bidimensional abrangente e detecção por ionização em chama (GCxGCxFID) foi empregada para detectar artefatos formados durante o preparo da amostra de méis, que poderiam ser prejudiciais ao processo de identificação de sua origem floral. O método foi otimizado utilizando-se planejamento multivariado. Para isso, uma mistura de diferentes tipos de méis brasileiros foi usada como modelo. Os artefatos de extração identificados foram classificados como resultantes da manipulação através do HS. A influência da temperatura e do tempo de exposição ao tratamento térmico também foi avaliada. A identificação da fração volátil da mistura de mel foi realizada por GCxGCxFID e cromatografia gasosa acoplada à espectrometria de massas com analisador quadrupolar (GC-QMS) comparando-se o índice de retenção linear com programação de temperatura obtido na primeira dimensão (D-LTPRI), calculado a partir dos cromatogramas obtidos por GCxGCxFID, e os índices obtidos por GC-QMS para as mesmas amostras. Esta identificação foi confirmada por cromatografia gasosa bidimensional abrangente combinada a um espectrômetro de massas por tempo de vôo (GCxGCxTOFMS). Portanto, a identificação e detecção de artefatos de extração previamente desconhecidos é atribuída às vantagens da GCxGC. A GCxGCxFID combinada com ferramentas quimiométricas foi empregada para classificar algumas amostras de méis de diferentes origens do Piauí-Brasil. A GCxGCxQMS foi empregada para identificação dos voláteis de algumas destas amostras. A combinação de HS-SPME - (GCxGC ou GC) com o poder de identificação do detector MS, juntamente com índices de retenção e de métodos quimiométricos forneceram informações valiosas sobre a classificação química dos méis / Abstract: Solid phase microextraction through headspace (HS-SPME) was otimizated by a multivariate design. This technique combined with comprehensive two-dimensional gas chromatography with flame ionization detection (GCxGC-FID) was employed to detect potential artifacts formed during preparation of honey samples, that could possibly be relevant to the identification of its floral origin. A mixture of different types of brazilian honeys was used as the model sample. The extraction artifacts identified were classified as resulting from HS manipulation. The influence of temperature and time exposure of the thermal treatment was also evaluated. The identification of the volatile fraction of the honey blend was performed through combination of GCxGC-FID and GC coupled to quadrupole mass spectrometry (GC-QMS) by comparing the one dimensional linear temperature programmed retention index (D-LTPRI) calculated from GCxGCxFID chromatograms to that of chromatograms of the same samples obtained on GC-QMS. This identification was confirmed by GCxGC combined with a time-of-flight mass analyzer (GCxGC-TOFMS). Therefore, the identification and detection of previously unknown extraction artifacts is attributed to advantages of GCxGC. GCxGCxFID in combination with chemometric tools was employed to classify some honey samples from different origins from Piauí-Brazil. GCxGCxQMS was employed for the identification of the volatiles from some one of these samples. The combination of HS-SPME - (GCxGC or GC) and the qualitative information of MS, retention index and chemometric methods may be able to provide valuable information on the chemical classification of honeys / Doutorado / Quimica Analitica / Doutor em Ciências
93

Comparison of Medical and Forensic Profiling Potential of Volatile Biomarkers from Different Biological Specimens from Individuals and Across Populations

Kusano, Maiko 28 October 2010 (has links)
There is limited scientific knowledge on the composition of human odor from different biological specimens and the effect that physiological and psychological health conditions could have on them. There is currently no direct comparison of the volatile organic compounds (VOCs) emanating from different biological specimens collected from healthy individuals as well as individuals with certain diagnosed medical conditions. Therefore the question of matching VOCs present in human odor across various biological samples and across health statuses remains unanswered. The main purpose of this study was to use analytical instrumental methods to compare the VOCs from different biological specimens from the same individual and to compare the populations evaluated in this project. The goals of this study were to utilize headspace solid-phase microextraction gas chromatography mass spectrometry (HS-SPME-GC/MS) to evaluate its potential for profiling VOCs from specimens collected using standard forensic and medical methods over three different populations: healthy group with no diagnosed medical or psychological condition, one group with diagnosed type 2 diabetes, and one group with diagnosed major depressive disorder. The pre-treatment methods of collection materials developed for the study allowed for the removal of targeted VOCs from the sampling kits prior to sampling, extraction and analysis. Optimized SPME-GC/MS conditions has been demonstrated to be capable of sampling, identifying and differentiating the VOCs present in the five biological specimens collected from different subjects and yielded excellent detection limits for the VOCs from buccal swab, breath, blood, and urine with average limits of detection of 8.3 ng. Visual, Spearman rank correlation, and PCA comparisons of the most abundant and frequent VOCs from each specimen demonstrated that each specimen has characteristic VOCs that allow them to be differentiated for both healthy and diseased individuals. Preliminary comparisons of VOC profiles of healthy individuals, patients with type 2 diabetes, and patients with major depressive disorder revealed compounds that could be used as potential biomarkers to differentiate between healthy and diseased individuals. Finally, a human biological specimen compound database has been created compiling the volatile compounds present in the emanations of human hand odor, oral fluids, breath, blood, and urine.
94

Exhaled Breath Analysis of Smokers Using CMV-GC/MS

Hamblin, D'Nisha D. 24 May 2016 (has links)
The aim of this research was to demonstrate the potential of the novel pre-concentration device, capillary microextraction of volatiles (CMV), for breath analysis. The CMV offers dynamic sampling of volatile organic compounds with its simple coupling to a GC inlet for GC/MS analysis, avoiding expensive thermal desorption instrumentation needed for sorbent tubes, as well as an increased surface area over a single SPME fiber. CMV collectively identified 119 compounds in the breath of 13 self-reported smokers and 7 nonsmokers. The presence and intensity of twelve compounds were used to classify all the nonsmokers 100% of the time using Principal Component Analysis to elucidate the groupings. In some cases, nicotine was not detected in smokers and they were confused with the nonsmokers. Nicotine was detected in the breath of 69% of smokers with an average mass of 143 ± 31 pg for cigarette smokers from the approximate 5 L sample of breath collected. The successful use of the CMV sampler and preconcentration of breath to distinguish between smokers and nonsmokers served as a proof of concept for future applications of the CMV for detection of marijuana smokers’ breath for impaired driver management.
95

Evaluation of Cryofocusing Capillary Microextraction of Volatiles for Improved Detection of Organic Gunshot Residue on the Hands of Shooters

Mulloor, Jerome 24 March 2017 (has links)
The capillary microextraction of volatiles (CMV) device was equipped with a novel Peltier cooler to investigate cryofocused extraction of organic gunshot residue (OGSR) for the first time. Prior research demonstrated the CMV’s capabilities for detecting nitroglycerin, 2,4-dinitrotoluene, diphenylamine, and ethyl centralite on shooters’ hands via gas chromatography-mass spectrometry. Further method development increased the recoveries of these four target compounds with an optimal 20-minute equilibrium time at 80˚C followed by extracting 3 L at a 1 L/min flow rate. The Cryo-CMV was evaluated for detection of semi-volatile OGSR compounds. The unique challenges presented with sampling of semi-volatiles were overcome by sample heating, applying high (>1 L/min) sampling flow rates and heating the transfer line between the container and cooled CMV. Cryofocusing at -10˚C provided increased recoveries for smokeless powders and OGSR compounds and therefore demonstrates excellent potential for other forensic applications with analysis of VOCs from fire debris and illicit drugs.
96

Improved Dynamic Headspace Sampling and Detection using Capillary Microextraction of Volatiles Coupled to Gas Chromatography Mass Spectrometry

Fan, Wen 14 November 2013 (has links)
Sampling and preconcentration techniques play a critical role in headspace analysis in analytical chemistry. My dissertation presents a novel sampling design, capillary microextraction of volatiles (CMV), that improves the preconcentration of volatiles and semivolatiles in a headspace with high throughput, near quantitative analysis, high recovery and unambiguous identification of compounds when coupled to mass spectrometry. The CMV devices use sol-gel polydimethylsiloxane (PDMS) coated microglass fibers as the sampling/preconcentration sorbent when these fibers are stacked into open-ended capillary tubes. The design allows for dynamic headspace sampling by connecting the device to a hand-held vacuum pump. The inexpensive device can be fitted into a thermal desorption probe for thermal desorption of the extracted volatile compounds into a gas chromatography-mass spectrometer (GC-MS). The performance of the CMV devices was compared with two other existing preconcentration techniques, solid phase microextraction (SPME) and planar solid phase microextraction (PSPME). Compared to SPME fibers, the CMV devices have an improved surface area and phase volume of 5000 times and 80 times, respectively. One (1) minute dynamic CMV air sampling resulted in similar performance as a 30 min static extraction using a SPME fiber. The PSPME devices have been fashioned to easily interface with ion mobility spectrometers (IMS) for explosives or drugs detection. The CMV devices are shown to offer dynamic sampling and can now be coupled to COTS GC-MS instruments. Several compound classes representing explosives have been analyzed with minimum breakthrough even after a 60 min. sampling time. The extracted volatile compounds were retained in the CMV devices when preserved in aluminum foils after sampling. Finally, the CMV sampling device were used for several different headspace profiling applications which involved sampling a shipping facility, six illicit drugs, seven military explosives and eighteen different bacteria strains. Successful detection of the target analytes at ng levels of the target signature volatile compounds in these applications suggests that the CMV devices can provide high throughput qualitative and quantitative analysis with high recovery and unambiguous identification of analytes.
97

Microextrações em fase líquida: antimicrobianos em amostras aquosas ambientais / Microextration in liquid phase: antimicrobials in environmental samples

Adriel Martins Lima 14 July 2017 (has links)
Águas residuárias são continuamente contaminadas por fármacos. Dentre estes fármacos, os antimicrobianos causam grande preocupação pelos impactos sobre o desenvolvimento de resistência bacteriana. As principais fontes de contaminação destes fármacos são efluentes urbanos, hospitalares, de fazendas e de algumas indústrias. A complexidade das matrizes ambientais tais como águas residuárias é uma das principais dificuldades para extrair e detectar fármacos, fazendo-se necessário o uso de técnicas de preparo de amostra para a extração destes compostos de interesse. Técnicas clássicas como a extração líquido-líquido (LLE) e a extração em fase sólida (SPE) são largamente usadas para extração de fármacos nesse tipo de matriz, porém estas técnicas não atendem amplamente aos princípios da química verde. Dessa forma, novas técnicas, mais alinhadas à responsabilidade ambiental, têm sido desenvolvidas. Neste âmbito apresenta-se o desenvolvimento e a validação de um método de microextração líquido-líquido para extração e detecção de sulfonamidas e o desenvolvimento e otimização de um método utilizando planejamento experimental para a extração de fluoroquinolonas em águas residuárias. Foi possível obter-se o limite de detecção de 0,2 ng mL-1 para as sulfonamidas analisadas, este LD é relativamente baixo considerando que o detector que foi utilizado não possuía a possibilidade de fazer análises no modo MS/MS, o que certamente reduziria ainda mais o LD. Com os desenvolvimentos desse trabalho tornou-se possível a utilização de apenas 1 mL de solvente orgânico para a pré-concentração off-line, Esta etapa, adicionada a uma outra pré-concentração online (column switching) permitiu a extração dos analitos com a obtenção de um LD relativamente baixo, a partir de apenas 7 mL de amostra. / Drugs are continuously contaminating wastewater. Among these drugs antimicrobials cause great concern for the impacts on the development of bacterial resistance. The main sources of contamination by these drugs are urban effluents, hospitals, farms and some industries. The complexity of the environmental matrices such as wastewater is one of the main difficulties in extracting and detecting drugs, bringing up the need to use sample preparation techniques for the extraction of the interest compounds. Classical techniques such as liquid-liquid extraction (LLE) and solid phase extraction (SPE) are widely used for drug extraction in this type of matrix, but these techniques do not largely meet the principles of green chemistry. In this way, new techniques, more aligned with environmental responsibility, have been developed. In this context, this thesis presents the development and validation of a liquid-liquid microextraction method for sulfonamide extraction and detection and the development and optimization of a method using experimental design for the extraction of fluoroquinolones presented in wastewater. It was possible to obtain a limit of detection (LD) of 0.2 ng mL-1 for the sulfonamides analyzed, this LD is relatively low considering that the detector that was used did not have the possibility to perform analyzes in the MS/MS mode, which certainly would further reduce the LD. With the development of this thesis, it became possible to use only 1 mL of organic solvent for the off-line preconcentration of the analytes. This step, added to another online preconcentration (column switching) allowed the extraction of the analytes obtaining relatively low LDs, from just 7 mL of the sample.
98

Critical Comparison of Total Vaporization-Solid Phase Microextraction vs Headspace-Solid Phase Microextraction

Alexandra Michelle Train (10873377) 05 August 2021 (has links)
<p>Solid Phase Microextraction (SPME) is a popular sampling technique that can be paired with Gas Chromatography/Mass Spectrometry (GC-MS). SPME-GC-MS is used in forensic chemistry due to its simplification of the sample preparation process. Headspace-Solid Phase Microextraction (HS-SPME) is a technique where the sample is heated to generate volatiles in the headspace of the vial. A SPME fiber is then inserted into the vial and the compounds in the headspace will bind to the fiber. Total Vaporization- Solid Phase Microextraction (TV-SPME) is a technique that is derived from the HS-SPME technique. </p><p>In Chapter 1, the critical comparison of HS-SPME and TV-SPME is discussed. Samples including marijuana, essential oils, and CBD oil were utilized to compare the two techniques. The compounds of interest in marijuana are the three main cannabinoids: cannabinol (CBN), cannabidiol (CBD), and tetrahydrocannabinol (THC). The sample preparation and GC-MS parameters were kept the same for all samples to determine which SPME technique works best for these sample types and yielded the greatest sensitivity. It was found that HS-SPME shows greater sensitivity with CBN and equivalent sensitivity with essential oils, THC and CBD. </p><p>In Chapter 2, the detection of synthetic cannabinoids utilizing liquid-liquid injection as well as HS-SPME and TV-SPME is discussed. The detection of these compounds is important because this type of drug has become more prevalent in the United States because they can be chemically altered slightly so they still have the effects of a drug but can evade drug legislation. The detection of synthetic cannabinoids using liquid injection was found to be successful but detection using HS-SPME and TV-SPME was found to be unsuccessful. </p>In Chapter 3, the analyses of real and artificial saliva utilizing HS-SPME and TV-SPME is discussed. Determining the compounds present in real saliva and artificial saliva will be of importance for future research into determining if the presence of drugs in saliva can be analyzed with these techniques. The analyses of real and artificial saliva were found to be successful using HS-SPME, without derivatization, and TV-SPME, with and without derivatization. Many of the compounds present in the real saliva were detected and were confirmed to be compounds regularly found in saliva by other scientific literature.
99

Critical Comparison of Total Vaporization- Solid Phase Microextraction vs Headspace- Solid Phase Microextraction

Train, Alexandra 05 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Solid Phase Microextraction (SPME) is a popular sampling technique that can be paired with Gas Chromatography/Mass Spectrometry (GC-MS). SPME-GC-MS is used in forensic chemistry due to its simplification of the sample preparation process. Headspace-Solid Phase Microextraction (HS-SPME) is a technique where the sample is heated to generate volatiles in the headspace of the vial. A SPME fiber is then inserted into the vial and the compounds in the headspace will bind to the fiber. Total Vaporization- Solid Phase Microextraction (TV-SPME) is a technique that is derived from the HS-SPME technique. In Chapter 1, the critical comparison of HS-SPME and TV-SPME is discussed. Samples including marijuana, essential oils, and CBD oil were utilized to compare the two techniques. The compounds of interest in marijuana are the three main cannabinoids: cannabinol (CBN), cannabidiol (CBD), and tetrahydrocannabinol (THC). The sample preparation and GC-MS parameters were kept the same for all samples to determine which SPME technique works best for these sample types and yielded the greatest sensitivity. It was found that HS-SPME shows greater sensitivity with CBN and equivalent sensitivity with essential oils, THC and CBD. In Chapter 2, the detection of synthetic cannabinoids utilizing liquid-liquid injection as well as HS-SPME and TV-SPME is discussed. The detection of these compounds is important because this type of drug has become more prevalent in the United States because they can be chemically altered slightly so they still have the effects of a drug but can evade drug legislation. The detection of synthetic cannabinoids using liquid injection was found to be successful but detection using HS-SPME and TV-SPME was found to be unsuccessful. In Chapter 3, the analyses of real and artificial saliva utilizing HS-SPME and TV-SPME is discussed. Determining the compounds present in real saliva and artificial saliva will be of importance for future research into determining if the presence of drugs in saliva can be analyzed with these techniques. The analyses of real and artificial saliva were found to be successful using HS-SPME, without derivatization, and TV-SPME, with and without derivatization. Many of the compounds present in the real saliva were detected and were confirmed to be compounds regularly found in saliva by other scientific literature.
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Mikroextrakce DNA z rostlinných tkání zeleniny / DNA microextraction from plant vegetable matrix

Cesnak, Filip January 2018 (has links)
The aim of the thesis was the comparison of two DNA microextraction methods with the use of magnetic beads from food of plant origin. Samples had disparate and complex matrices and were either raw (broccoli) or processed (strawberry jam). The first method uses a magnetic separator for the manipulation of magnetic beads and was used as a standart for the comparison. The second method uses a paramagnetic needle, the advantage of which should be the possibility to isolate DNA of higher quality without a significant contamination by polyphenolic compounds or proteins. The former method was validated by statistic analysis of results obtained from both methods. DNA quality was judged by testing the amplificability of isolated DNA via PCR. The amplified products were visualised on an agarose gel with electrophoresis.

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