Orientador: Fabio Augusto / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-10T22:09:41Z (GMT). No. of bitstreams: 1 Biajoli_AndreFranciscoPivato_M.pdf: 976777 bytes, checksum: 46d1432f77507bee6dedced57031e3c3 (MD5) Previous issue date: 2008 / Resumo: Este trabalho descreve a obtenção de fibras para microextração em fase sólida a partir do processo sol-gel utilizando-se 3-aminopropiltrimetoxissilano (APTMS) como precursor/modificador orgânico e polidimetilsiloxano hidroxiterminado (PDMS-OH) como modificador orgânico. O material preparado foi caracterizado física e quimicamente através de espectroscopia de absorção no infravermelho e análise termogravimétrica. As fibras recobertas com este material foram avaliadas morfologicamente através de microscopia eletrônica de varredura e caracterizadas analiticamente através do estudo de seus perfis de extração e de dessorção, além de terem sido comparadas com fibras comerciais. Como resultados, verificou-se que os recobrimentos produzidos podem ser utilizados em temperaturas de até 300 °C e que estes apresentam uma morfologia irregular, aspecto favorável para dispositivos de SPME. O perfil de extração mostrou que a fibra possui tempos de equilíbrio rápidos para hidrocarbonetos aromáticos (da ordem de 5 min); o perfil de dessorção mostrou que, após 5 s de injeção, os mesmos analitos são completamente removidos do recobrimento. Comparada com fibras comerciais de poliacrilato (PA - polar) e PDMS (apolar), a fibra sol-gel apresentou melhores propriedades sortivas tanto no tocante a compostos polares (ácidos carboxílicos e álcoois) quanto a compostos de media polaridade (ésteres). A fibra sol-gel foi aplicada com sucesso em determinações quantitativas de clorofenóis em madeiras e águas / Abstract: This work describes the preparation of Solid Phase Microextraction Fibers through the sol-gel process using 3-aminopropyltrimethoxysilane as precursor/organic modifier and polydimethylsiloxane (PDMS) as organic modifier. The chemical and physical properties of the material obtained were studied through infrared absorption spectroscopy and thermogravimetric analysis. The morphology of the fibers obtained were evaluated by scanning electron microscopy; their analytical properties were studied through extraction and desorption profiles and also through comparison with commercial SPME fibers. As results, it was observed that the coatings prepared presented an irregular, rugged surface, desirable characteristics for SPME devices, and may be used up to 300 °C with no thermal decomposition. The extraction profile showed that the fiber allows fast equilibration times (in the order of 5 min) and fast desorption kinetics, with 5 s being needed for complete removal of extracted compounds from the fiber coating. Compared to commercial polyacrylate (PA, polar) and PDMS (apolar) fibers, the sol-gel fiber presented enhanced sorptive properties for polar compounds (carboxylic acids and alcohols) as well as for intermediate polarity ones (esters). The sol-gel fiber was successfully applied to quantitative determination of chlorophenols in wood and water / Mestrado / Quimica Analitica / Mestre em Química

As recentes técnicas miniaturizadas de preparo de amostra, microextração em fase sólida (SPME) e in tube SPME, apresentam uma série de vantagens em relação aos métodos clássicos de extração (extração líquido-líquido e extração em fase sólida), tais como: não requer instrumentação analítica sofisticada, utilização de pequenas quantidades de solventes orgânicos, rápido processo operacional, permite automação das análises, a reutilização das fases extratoras, e integra em um único sistema a extração, concentração e introdução da amostra no cromatográfico. Esta dissertação tem como objetivo a padronização, validação e comparação dos métodos SPME/LC-UV com dessorção off line e in tube SPME/LC-UV, para a análise dos antidepressivos da nova geração (mirtazapina, citalopram, paroxetina, duloxetina, fluoxetina e sertralina) em amostras de plasma para fins de monitorização terapêutica. As variáveis: fase extratora, pH da matriz, tempo e temperatura de extração e de dessorção e força iônica apresentaram grande influência na eficiência do processo SPME. O método SPME/LC-UV padronizado, apresentou limite de quantificação (LQ) de 25 a 50 ng mL-1, ampla faixa de linearidade (LQ ? 500 ng mL-1, r2 > 0,9970) e precisão inter ensaios com coeficientes de variação menor que 15% para todos os analitos. Apesar das baixas taxas de recuperação obtidas, de 8,1% (citalopram) a 17,1% (mirtazapina), o método SPME/LC-UV apresentou seletividade e sensibilidade analítica adequada. As variáveis: pH da matriz, fluxo e número de ciclos aspirar/dispensar e volume de amostra apresentaram grande influência na eficiência do processo in tube SPME. A etapa de precipitação de proteínas do plasma, anterior ao processo de extração, foi necessária para a eliminação dos compostos endógenos. O método in tube SPME/LC-UV padronizado apresentou seletividade adequada, precisão inter ensaios com coeficiente de variação menor que 10%, LQ de 20 a 50 ng mL-1, linearidade na faixa de concentração do LQ a 500 ng mL-1, com r2 > 0,9983 para todos os analitos e recuperação absoluta de 5,32% (mirtazapina) a 43,5% (sertralina). A técnica in tube SPME, quando comparada à SPME, permitiu a automação das análises, menor exposição do analista às amostras biológicas e solventes orgânicos, menor tempo de análise e menor volume de amostra de plasma. A eficácia dos métodos, SPME/LC-UV e in tube SPME/LC-UV, foi comprovada através das análises de amostras de plasma de pacientes em terapia com os antidepressivos, para fins de monitorização terapêutica. / The recent miniaturized sample techniques preparation, solid phase microextraction (SPME) and in tube SPME, present several advantages when compared with classic extraction methods (liquid-liquid extraction and solid phase extraction), such as: it does not require sophisticated analytical instrumentation, use small organic solvent amounts, fast operational process, automation of the analyses, reuse extraction phases, and incorporates, into a single procedure, sample extraction, concentration and sample introduction. The aim of this work is development, validation and comparison of methods SPME/LC-UV with off line desorption and in tube SPME/LC-UV, for analyses of antidepressants of the new generation (mirtazapine, citalopram, paroxetine, duloxetine, fluoxetine and sertraline) in plasma samples for therapeutic drug monitoring. Variables: extraction phase, matrix pH, time and temperature of extraction and desorption and ionic strength showed great influence in SPME process efficiency. The method SPME/LC-UV presented limit of quantification (LOQ) variety from 25 to 50 ng mL-1, wide range the of linearity (LOQ 500 ng mL-1, r2 > 0.9970) and interassays precision with coefficient of variation lower than 15% for all analytes. Although the low recovery, from 8.1% (citalopram) to 17.1% (mirtazapine), the method SPME/LC-UV presented adequate selectivity and analytical sensitivity. Variables: matrix pH, flow and number of aspirate/dispense cycles and sample volume showed great influence in the in tube SPME process efficiency. The protein precipitation of the plasma steps, previous to the extraction process, was necessary for the endogenous compounds elimination. The method in tube SPME/LC showed adequate selectivity, interassays precision with coefficient of variation lower than 10%, LOQ variety from 20 to 50 ng mL-1, linearity in range concentration from LOQ to 500 ng mL-1, with r2 > 0.9983 for all analytes and recovery from 5.32% (mirtazapine) to 43.5% (sertraline). The technique in tube SPME, compared with the SPME, permitted the automation of the analyses, minor exposition of the analyst to the biological samples and organic solvent, shorter analyses time and minor plasma sample volume. The effectiveness methods, SPME/LC-UV and in tube SPME/LC-UV, was proven through the analyses of plasma samples of patients in therapy with antidepressants, for therapeutic drug monitoring.

Biological fluids are commonly analyzed in clinical and forensic studies for drug concentration measurements. Conventional quantification procedures are always associated with lengthy sample pretreatment steps to eliminate the interfering compounds that potentially exist in complex biological matrices. The objective of this study was to address these problems employing solid-phase microextraction (SPME) technique. Antibodies (Abs) were employed to serve as an extremely specific extraction phase for direct extraction of analytes from untreated biological matrices based on their exquisite selectivity for antigens (Ags). Much of the research was focused on selecting the most appropriate antibody (Ab) for a particular application based on evaluation of characteristics of various types of Abs obtained from four suppliers. Abs’ binding characteristics were evaluated before and after immobilization in terms of affinity, valence, homogeneity, capacity and cross-reactivity for three benzodiazepines. The performance of immunoaffinity probes of the same type provided by different suppliers was found to be comparable. Finally, the probes’ utility for extraction of benzodiazepines from plasma samples was evaluated. The limit of detection of the method developed in this work was 0.01 ng/mL with upper limits of quantification of 0.5 ng/mL in buffer and 2 ng/mL in plasma. The method’s precision was 12% for extraction from buffer and less than 10% for extraction from plasma. With limits of detection similar to the current state-of-the-art methods available for quantification of drugs in biological matrices, the method presented in this thesis was found advantageous compared to other available methods due to its simplified sample preparation procedure.

Increasing the efficiency of the methods used through the development and trial of novel pharmaceutical compounds is an important step to reduce the time required to develop new medical treatments. Before a drug can be used, multiple analyses are required to obtain their physical, chemical and biopharmaceutical properties. The aim of this thesis will be to show that SPME can be an advantageous technique in the field of pharmaceutical development due to its use both as a tool to determine the physical properties of drugs and to facilitate clinical development by easily and cheaply providing high-throughput analysis of compounds in biological fluids. It will be demonstrated that a novel coating of triacontyl is capable of rapid equilibrium while providing enhanced sensitivity towards benzodiazepines when compared to shorter chain alkyl extraction phases. The same extraction phase will prove capable of providing a rapid determination of the hydrophobicity of structurally diverse β-blocker drugs while maintaining the use of solvents and analyte to a minimum. We will then show the possibility to produce large quantities of fibers using a robotic apparatus for high-throughput handling of samples. The 96 fiber plate produced will then be used to analyze the target drug loratadine in human plasma using the same apparatus.

Biological fluids are commonly analyzed in clinical and forensic studies for drug concentration measurements. Conventional quantification procedures are always associated with lengthy sample pretreatment steps to eliminate the interfering compounds that potentially exist in complex biological matrices. The objective of this study was to address these problems employing solid-phase microextraction (SPME) technique. Antibodies (Abs) were employed to serve as an extremely specific extraction phase for direct extraction of analytes from untreated biological matrices based on their exquisite selectivity for antigens (Ags). Much of the research was focused on selecting the most appropriate antibody (Ab) for a particular application based on evaluation of characteristics of various types of Abs obtained from four suppliers. Abs’ binding characteristics were evaluated before and after immobilization in terms of affinity, valence, homogeneity, capacity and cross-reactivity for three benzodiazepines. The performance of immunoaffinity probes of the same type provided by different suppliers was found to be comparable. Finally, the probes’ utility for extraction of benzodiazepines from plasma samples was evaluated. The limit of detection of the method developed in this work was 0.01 ng/mL with upper limits of quantification of 0.5 ng/mL in buffer and 2 ng/mL in plasma. The method’s precision was 12% for extraction from buffer and less than 10% for extraction from plasma. With limits of detection similar to the current state-of-the-art methods available for quantification of drugs in biological matrices, the method presented in this thesis was found advantageous compared to other available methods due to its simplified sample preparation procedure.

Increasing the efficiency of the methods used through the development and trial of novel pharmaceutical compounds is an important step to reduce the time required to develop new medical treatments. Before a drug can be used, multiple analyses are required to obtain their physical, chemical and biopharmaceutical properties. The aim of this thesis will be to show that SPME can be an advantageous technique in the field of pharmaceutical development due to its use both as a tool to determine the physical properties of drugs and to facilitate clinical development by easily and cheaply providing high-throughput analysis of compounds in biological fluids. It will be demonstrated that a novel coating of triacontyl is capable of rapid equilibrium while providing enhanced sensitivity towards benzodiazepines when compared to shorter chain alkyl extraction phases. The same extraction phase will prove capable of providing a rapid determination of the hydrophobicity of structurally diverse β-blocker drugs while maintaining the use of solvents and analyte to a minimum. We will then show the possibility to produce large quantities of fibers using a robotic apparatus for high-throughput handling of samples. The 96 fiber plate produced will then be used to analyze the target drug loratadine in human plasma using the same apparatus.

As recentes técnicas miniaturizadas de preparo de amostra, microextração em fase sólida (SPME) e in tube SPME, apresentam uma série de vantagens em relação aos métodos clássicos de extração (extração líquido-líquido e extração em fase sólida), tais como: não requer instrumentação analítica sofisticada, utilização de pequenas quantidades de solventes orgânicos, rápido processo operacional, permite automação das análises, a reutilização das fases extratoras, e integra em um único sistema a extração, concentração e introdução da amostra no cromatográfico. Esta dissertação tem como objetivo a padronização, validação e comparação dos métodos SPME/LC-UV com dessorção off line e in tube SPME/LC-UV, para a análise dos antidepressivos da nova geração (mirtazapina, citalopram, paroxetina, duloxetina, fluoxetina e sertralina) em amostras de plasma para fins de monitorização terapêutica. As variáveis: fase extratora, pH da matriz, tempo e temperatura de extração e de dessorção e força iônica apresentaram grande influência na eficiência do processo SPME. O método SPME/LC-UV padronizado, apresentou limite de quantificação (LQ) de 25 a 50 ng mL-1, ampla faixa de linearidade (LQ ? 500 ng mL-1, r2 > 0,9970) e precisão inter ensaios com coeficientes de variação menor que 15% para todos os analitos. Apesar das baixas taxas de recuperação obtidas, de 8,1% (citalopram) a 17,1% (mirtazapina), o método SPME/LC-UV apresentou seletividade e sensibilidade analítica adequada. As variáveis: pH da matriz, fluxo e número de ciclos aspirar/dispensar e volume de amostra apresentaram grande influência na eficiência do processo in tube SPME. A etapa de precipitação de proteínas do plasma, anterior ao processo de extração, foi necessária para a eliminação dos compostos endógenos. O método in tube SPME/LC-UV padronizado apresentou seletividade adequada, precisão inter ensaios com coeficiente de variação menor que 10%, LQ de 20 a 50 ng mL-1, linearidade na faixa de concentração do LQ a 500 ng mL-1, com r2 > 0,9983 para todos os analitos e recuperação absoluta de 5,32% (mirtazapina) a 43,5% (sertralina). A técnica in tube SPME, quando comparada à SPME, permitiu a automação das análises, menor exposição do analista às amostras biológicas e solventes orgânicos, menor tempo de análise e menor volume de amostra de plasma. A eficácia dos métodos, SPME/LC-UV e in tube SPME/LC-UV, foi comprovada através das análises de amostras de plasma de pacientes em terapia com os antidepressivos, para fins de monitorização terapêutica. / The recent miniaturized sample techniques preparation, solid phase microextraction (SPME) and in tube SPME, present several advantages when compared with classic extraction methods (liquid-liquid extraction and solid phase extraction), such as: it does not require sophisticated analytical instrumentation, use small organic solvent amounts, fast operational process, automation of the analyses, reuse extraction phases, and incorporates, into a single procedure, sample extraction, concentration and sample introduction. The aim of this work is development, validation and comparison of methods SPME/LC-UV with off line desorption and in tube SPME/LC-UV, for analyses of antidepressants of the new generation (mirtazapine, citalopram, paroxetine, duloxetine, fluoxetine and sertraline) in plasma samples for therapeutic drug monitoring. Variables: extraction phase, matrix pH, time and temperature of extraction and desorption and ionic strength showed great influence in SPME process efficiency. The method SPME/LC-UV presented limit of quantification (LOQ) variety from 25 to 50 ng mL-1, wide range the of linearity (LOQ 500 ng mL-1, r2 > 0.9970) and interassays precision with coefficient of variation lower than 15% for all analytes. Although the low recovery, from 8.1% (citalopram) to 17.1% (mirtazapine), the method SPME/LC-UV presented adequate selectivity and analytical sensitivity. Variables: matrix pH, flow and number of aspirate/dispense cycles and sample volume showed great influence in the in tube SPME process efficiency. The protein precipitation of the plasma steps, previous to the extraction process, was necessary for the endogenous compounds elimination. The method in tube SPME/LC showed adequate selectivity, interassays precision with coefficient of variation lower than 10%, LOQ variety from 20 to 50 ng mL-1, linearity in range concentration from LOQ to 500 ng mL-1, with r2 > 0.9983 for all analytes and recovery from 5.32% (mirtazapine) to 43.5% (sertraline). The technique in tube SPME, compared with the SPME, permitted the automation of the analyses, minor exposition of the analyst to the biological samples and organic solvent, shorter analyses time and minor plasma sample volume. The effectiveness methods, SPME/LC-UV and in tube SPME/LC-UV, was proven through the analyses of plasma samples of patients in therapy with antidepressants, for therapeutic drug monitoring.

Orientador: Fabio Augusto / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-04T15:09:26Z (GMT). No. of bitstreams: 1 Silva_RogerioCesarda_D.pdf: 4524361 bytes, checksum: 24333539b89a414df416bbcf9e0ee5bd (MD5) Previous issue date: 2005 / Doutorado / Quimica Analitica / Doutor em Quimica

The toxicity and ubiquitousness of PAHs within different terrestrial environments has been an increasing cause for concern amongst environmental scientists in the last decades, in particular regarding their transport within the soil. In an attempt to understand the role of pure inorganic phases in PAH-mobility; experiments exposing mineral soil components with low organic matter content to a PAH-representative were carried out. The systems consisted of four different mineral phases (quartz sand, hematite, iron coated quartz sand and montmorillonite) which were individually exposed to naphthalene in electrolyte solutions prepared at increasing ionic strengths (NaNO3: 0.001 M; 0.01 M; 0.1 M) and pH (4.0 and 5.5). All experiments were conducted over at 24 reaction intervals and at ambient temperature conditions.Mineral geosorbents are traditionally known to be poor PAH-scavengers; in particular when compared to organic, high surface area materials such as activated carbons. On this basis, a preliminary validation experiment (Proof of Concept Experiment) was conducted to test the sensitivity of the selected extraction method (SPME) under complete uptake (activated carbon) and very low uptake (quartz sand) conditions. By extracting and analysing the supernatant after 24 hr of exposure of both sorbents to naphthalene under identical conditions it was concluded that SPME was a feasible extraction technique, yielding good reproducibility (n=3, inter-day RSD%= 11.18% ) even at very low PAH concentrations (0.2 µg / L). The final concentration of naphthalene in the sample supernatant after 24 hours was determined by GC-FID. All samples were extracted using the Solid Phase Microextraction method developed during the Proof of Concept which allowed the rapid extraction of naphthalene in the headspace HS-SPME (extraction time = 3 minutes) using temperature control and ultrasonication as means of agitation. Each sample set included triplicates of blanks and samples as well as calibration standards (in duplicate where possible)Out of the four minerals, only quartz sand and hematite showed a slight tendency towards naphthalene removal from solution; a finding which correlated well with increasing ionic strength. The other two minerals did not show any such trend and the results were deemed inconclusive. In regards to the results for quartz and hematite; the detected uptake was found to be below the sensitivity of the current SPME extraction method according to the error analysis carried out by comparing the sample and blank means whilst accounting for error equal to 1σ. The overlapping of both means in the majority of the samples indicated that both averages were too close to be accurately resolved (due to very low naphthalene uptake). Modifications to the SPME method could improve the reproducibility and decrease the spread of the data; however, this measure would only guarantee higher statistical confidence (95 %) and not higher naphthalene uptake by these minerals. These observations lead to the conclusion that naphthalene was being salted out of solution rather than being removed by sorption; and under these experimental conditions it would not have been possible to detect any real PAH-mineral interaction. In view of this outcome, a different approach was attempted in order to detect surface reactions between the minerals and naphthalene. A series of preliminary (qualitative) surface analysis (AFM, XPS and ATR-FTIR) on pre-loaded mineral specimens were carried out in air at ambient temperature conditions. No naphthalene was positively identified on the surfaces of the studied sorbents. Factors such as molecular size, sorbents characteristics (i.e. roughness, surface charge) and loading conditions impeded the detection of the target molecules. Innovative sample preparation protocols as well as controlled analytical conditions would need to be implemented and evaluated before this kind of analytical tool can be used. The main outcome of this research work was the successful adaptation of SPME to the rapid extraction of naphthalene in electrolyte solutions at optimal and sub-optimal concentration levels; as the proof of concept preliminary experiment showed.

Although incipient fungal decay of wood may be difficult to detect early, it causes a significant decrease in wood strength. Developing a reliable method of decay identifica-tion to overcome wood replacement costs by non-destructive methods is necessary. This study investigates a possibility of identifying fungal volatile organic compounds (VOCs) as means of fungal detection using solid phase micro-extraction (SPME) coupled with gas chromatography–mass spectrometry (GC-MS). Volatile emissions from two brown rot (Gloeophyllum trabeum and Postia pla-centa) and two white rot (Trametes versicolor and Irpex lacteus) fungi on pine and aspen and their profiles related to wood mechanical strength and mass loss were investigated over 12 weeks. Principal component analysis of VOCs spectra differentiated volatiles from decayed and sound wood. Volatiles from two fungal species revealed distinct pat-terns of early and late degradation stages. SPME combined with GC-MS showed promissing results for non-destructive identification of incipient decay in wood struc-tures.