Different sample preparation methodologies were evaluated for the determination of pollutants in different matrices. The methods investigated were chosen on the merits of decreased sample preparation time and low toxic solvent consumption with the aim to provide viable alternatives to more laborious methods, such as, Soxhlet extraction. Techniques were developed to extract and quantify organic pollutants from contaminated soils and water. The results from shake flask extraction of aged phenolic contaminated soils were used in attempt to relate sorption to both the soil, and pollutant properties. This was to help gain an understanding of the transport and fate of phenols in different environmental situations. The partitioning (sorption/desorption) of radiolabelled phenols between aqueous solution and soil was investigated using a modified shake flask technique. This provides additional information which can be related to soil characteristics, hence pertaining to the fate mechanisms involved for phenols in the environment. The results from these investigations suggest that more than one factor contributes to the sorption of phenols in soils.

This thesis describes the design of a convenient format of solid phase microextraction (SPME) for bioanalysis in pharmaceutical industry and the validation of the approach to the application. An automated in-tip SPME technique coupled with liquid chromatography (LC) and tandem mass spectrometry (MS/MS) for high throughout drug analysis has been developed and applied to the quantitative determination of various drug compounds in different biological fluids from drug discovery to clinical development. The initial research in this thesis focused on a proof-of-concept study using manual multi-fiber approach to determine a drug compound in human plasma from a clinical trial. The proof-of-concept was achieved based on the validation data and a head-to-head comparison with conventional liquid-liquid extraction (LLE) method. An in-tip SPME technique was then proposed to explore the feasibility of SPME automation and two approaches of preparing in-tip SPME fibers were developed including fiber-packed and sorbent-packed fiber preparation. A simple and high throughput in-tip SPME fiber fabricating procedure based on polymer monoliths using photo-polymerization was introduced to prepare 96 fibers simultaneously. The biggest advantage of the in-tip SPME technique is that it is simple and easy to use for automation without introducing any additional devices and in the meantime, the simplicity of SPME is maintained. Automated in-tip SPME was applied to routine drug analysis in drug discovery and development environment. One case study involved the determination of vitamin D3 in human serum with derivatization and the in-tip SPME approach was compared with traditional LLE method using either tubes or 96-well plate extraction. Another study was to use hydrophilic interaction chromatography (HILIC) –MS/MS to determine three polar compounds, imipenem (IMP), cliastatin (CIL) and -lactamase inhibitor (BLI) simultaneously in different biological fluids including rat plasma and mouse blood. The results from both studies clearly demonstrated that in-tip SPME could be used as an alternative sample preparation method in bioanalytical analysis. Matrix effects in bioanalysis using automated in-tip SPME and LC-MS/MS were then thoroughly evaluated for the first time. Our study indicated that the assumption that SPME should provide sample clean up as effective as or better than solid phase extraction (SPE) with no or minimal matrix effects might not be always true, and matrix effects should be investigated in any SPME assays in bioanalysis. Comparisons between in-tip SPME and other automated SPME approaches such as blade/thin film geometries were performed, and the advantages and limitations of using SPME versus conventional sample preparation methods including protein precipitation (PPT), LLE and SPE were summarized. Strategies for in-tip SPME method development and validation and the potential applications and future directions of in-tip SPME in bioanalysis were discussed. Finally, kinetic models were established to describe SPME extraction and desorption processes in a complex matrix with both liquid and solid fiber coatings. The models were successfully applied to different scenarios to estimate the boundary layer (BL) thickness, extraction equilibrium time and total amount of analytes extracted at a given time. The excellent agreements between the model prediction results and experimental data indicated that the SPME modeling approach had great potentials to speed up SPME method development and fiber selection.

Orientadores: Marcia Miguel Castro Ferreira, Fabio Augusto / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-15T10:17:49Z (GMT). No. of bitstreams: 1 Ribeiro_JulianoSouza_D.pdf: 5735047 bytes, checksum: e7f146614953c780319857f147af11d5 (MD5) Previous issue date: 2009 / Resumo: Atualmente, o café é considerado a segunda bebida mais consumida em todo o mundo, sendo superado somente pela água. Esse consumo representa hoje, cerca de 60 bilhões de dólares anuais, contemplando desde a escolha do grão a ser plantado até o produto final comercializado. No mundo todo, especialistas e pesquisadores buscam meios para reconhecer, valorizar e promover padrões de qualidade para os melhores cafés. Porém, a qualidade da bebida tem se mostrado dependente de vários componentes simultaneamente, e sua avaliação é determinada pela prova ¿de xícara¿, realizada por profissionais experientes na arte de degustar café (provadores). Deste modo, este trabalho visou a construção de modelos quimiométricos de previsão de diversos atributos sensoriais do café arábica brasileiro, a partir da correlação entre o aroma e análises sensoriais. Para isso, a técnica analítica de microextração em fase sólida acoplada a cromatografia gasosa foi utilizada (SPME-GC). Um planejamento experimental realizado com as variáveis experimentais do sistema de SPME indicou as melhores condições para a extração simultânea da maioria dos picos cromatográficos. Com todo o sistema de extração otimizado, foram construídos modelos PLS de previsão para seis atributos sensoriais (acidez, amargor, aroma, bebida, corpo e qualidade global) descritos por provadores, a partir do perfil aromático de amostras de café torrado. Modelos com base em dados espectroscópicos (infravermelho próximo) também foram construídos. Os modelos de regressão PLS gerados a partir dos perfis cromatográficos dos voláteis de cafés arábica torrados e dos dados espectroscópicos previram adequadamente as notas dos seis atributos sensoriais estudados. Os erros de previsão desses modelos foram baixos e compatíveis com os erros médios das notas fornecidas pelos provadores / Abstract: Nowadays, coffee is considered the second most consumed beverage in the whole world, only being surpassed by water. This consumption represents about 60 billion dollars annually, from the choice of the seed to be planted until the final commercialized product. In the entire world, specialists and scientists search for ways to recognize, to promote and to valorize standards of quality for the best coffee beverages. However, the quality of the beverage depends on various compounds simultaneously, and its evaluation is determined by the cup profile carried out by experts in the art of sampling fresh coffee (cuppers). Thus, this work aimed at the construction of chemometric models for the prediction of diverse sensory attributes of Brazilian Arabica coffees from the correlation between their aromas and their sensory analyses. For this, the analytical technique used was solid phase microextraction followed by gas chromatography (SPME-GC). An experimental design carried out with the several variables of the SPME system indicated the best conditions for the simultaneous extraction of the majority of the chromatographic peaks. With the extraction system optimized, PLS prediction models for six sensory attributes (acidity, bitterness, flavour, cleanliness, body and overall quality) described by the cuppers were constructed from the flavour profile of roasted coffee samples. Spectroscopic models based on spectroscopic data (near infrared) were also constructed. The PLS regression models generated from the chromatographic profiles and of the spectroscopic data of roasted Arabica coffee adequately predicted notes of the six sensorial attributes studied. The prediction errors of these models were low and compatible with the average errors of notes supplied by the cuppers / Doutorado / Quimica Analitica / Doutor em Ciências

Orientador: Fabio Augusto / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-04T17:02:04Z (GMT). No. of bitstreams: 1 Oliveira_AnaMariade_D.pdf: 4464249 bytes, checksum: e1dcc40236e7dd94aa43a41c09928e8d (MD5) Previous issue date: 2005 / Doutorado / Quimica Analitica / Doutor em Ciências

This diploma thesis is focused on the problem of volatile aroma active compounds in chocolate, directly connected with the formation of chocolate aroma. Organoleptic properties of chocolate (aroma and taste) are the most important for evaluating by consumers. In this work four types of plain chocolate: Figaro Sweet Passion 70 % cacao, Figaro plain chocolate, Figaro for cooking and KAUMY chocolate glaze were tested. SPME method (fiber CAR/PDMS 85µm) in conjunction with gas chromatography was chosen for their analysis. Solid phase micro-extraction (SPME) is simple, sensitive, reproducible, rapid and low-cost method for evaluation of key odorant compounds found in cocoa and chocolate products. Using SPME-GC method total 56 aromatic compounds: 14 acids, 9 aldehydes, 8 ketones, 17 alcohols, 7 esters and 1 nitrogen compound were identified and quantified. Taste and aroma are the most important for evaluating of chocolate by consumer. Taste and aroma should be aromatic, pleasant and after used raw material. The single organoleptic properties (appearance, colour, taste, aroma and texture) were observed by sensory analysis using scale and also aroma and taste profiles of samples were created. The assessors were students and staffs faculty of chemistry BUT. The high content of alcohols (methanol, ethanol, propanol, butan-2,3-diol) and fatty acids was found in all types of chocolate , these compounds are probably important components of chocolate aroma. Some detected aromatic compounds doesn´t contribute positively to typical chocolate aroma. Unpleasant odour of these compounds often influences total flavour of chocolate, which was also proved by sensory evaluating.

It is common practice to add oxygenates, such as ethers or alcohols, to gasoline in areas suffering from ozone or smog problems in order to reduce pollution. The most commonly used oxygenates are ethanol (EtOH) and methyl tert-butyl ether (MTBE). However, MTBE is now forbidden by the environmental protection agency (EPA) because of the possibility of ground water contamination. The current trend is to use EtOH, therefore this work focuses on the analysis and quantification of EtOH in gasoline by solid phase microextraction (SPME). The major problem in quantifying EtOH in gasoline is the coelution of hydrocarbons with EtOH. There have been several approaches to solve this problem; among the chromatographic ones, three major types have been proposed: (1) the first one uses a detector selective for oxygen containing compounds; (2) the second one uses two or more columns; (3) and the third one uses an extraction step prior to GC analysis. In this work an extraction step with water is used prior to a solid phase microextraction (SPME) sample preparation coupled to a gas chromatographic (GC) analysis. Solid phase microextraction is a recent technique, invented by Pawliszyn in 1989, and available commercially since 1994. A fiber is used to extract small amounts (ppm, ppb, ppt) of analytes from a solution, usually water. The fiber is beneficial in concentrating analytes. Most work using SPME has been done with hydrophobic (non polar) analytes, extracted using a polydimethylsiloxane (PDMS; non polar) coating on a fused silica fiber. Since very little work has been done with polar analytes, the novel approach of this work is the extraction of EtOH. Since EtOH is the analyte of interest, a polar fiber, carboxen/polydimethyl siloxane (Car/PDMS) is used. Two methods are used for quantification of EtOH in gasoline: the method of a standard calibration curve, and the method of standard addition. They are both successful in quantifying the amount of EtOH in gasoline. The relative errors, with the method of standard addition, vary from 5.3% to 14%, while the ones with the method of calibration curve vary from 1.6% to 7.2%. Moreover, some extraction time studies for both direct and headspace sampling are performed. Direct sampling shows the presence of an equilibrium condition for the carboxen/PDMS fiber, for which no extraction theory is available. Conversely, headspace sampling shows no equilibrium state; after a sampling time of one hour, the amount of EtOH extracted decreases with sampling time. This is probably due to displacement of EtOH by other compounds in the fiber. / Master of Science

In any oil production company, one of the problems that is faced on a daily basis and which sometimes hinders the operation is corrosion. In the presence of dissolved oxygen in the water inside any vessel, tank, or pipeline, the oxygen attacks the steel to form iron oxides, and this result in corrosion of the steel. To prevent this, corrosion inhibitors are added to the oil and gas streams. These chemicals are based on aliphatic amines, which are soluble in water, to form a film to coat the steel and prevent it from the oxygen attacks. As a chemist in the laboratory, filming amines residuals should be monitored and optimized in order to make sure the system is protected against corrosion and that no excess chemical remains. This is classically done by lengthy liquid-liquid extraction of filming amines followed by colorimetric determination using spectrophotometry of the extract. SPME is an easy, rapid, and solvent free extraction technique which can be easily coupled with GC for separation and quantification, and is a good candidate to be used for this job. In this thesis, an introduction about corrosion problems and how to control and monitor them in the oil and gas industry will be shared, as well as a literature review about various methods used to determine amines in different matrices, followed by a description of the SPME procedure, including its theory, modes, fibers, and method development procedures. A flow-through system was used to simulate the process of flowing streams in pipelines during oil production and to provide unlimited sample volumes, which contributes iv to simplifying the calculation of the distribution constant between fiber and solution. Two different agitation methods were compared, which are stirring and sonication, in order to optimize the extraction time profiles of analytes. A method was developed to determine amines, using a flow-through system at the lowest detection limit possible. Different parameters were examined such as variation of pH, salt addition, and sand addition. It was found that the pH of the solution has to be adjusted in order to get better sensitivity for the desired analytes. Finally, in-fiber kinetic calibration was used to calculate the concentration of solutions at a short extraction time. This was possible by applying the dominant desorption approach using the same analytes as standards in the fiber. The experiment was successful in shortening the extraction time from 3 hours to 20 minutes, with less than 20% variation in concentrations between the actual and the calculated.

Utsläpp av lättflyktiga organiska föreningar (VOC) är ett växande mijlöproblem. Biofiltrering är ett relativt billigt sätt att rena luft förorenad med VOC. Biofiltrering har också en fördel i att föroreningen helt bryts ned och inte endast övergår i en annan form. Rapporten beskriver arbetet kring två biofilter av kolonntyp. Mikroberna som användes kom från främst träflis och jord. Som förorening användes limonen och α-pinen. Analys skedde med gaskromatografi. Vidare undersöktes om närvaro av silikonolja i filterbädden påverkade resultatet Reningskapaciteten uppgick i filtret utan olja till ca 10 - 12 g/m3.h under de första 25 dagarna i drift och ökade därefter till ca 15 - 20 g/m3.h. Motsvarande data för det oljeberikade filtret är ca 15 - 20 g/m3.h i båda fallen / Emissions of volatile organic compounds are a growing environmental problem. Biofiltration is a relatively cost efficient method to purify air polluted with VOC:s. Biofiltraion also has the benefit of completely degrading the pollutants rather than just transferring them into another phase/form. This report describes the work on two biofilters of column type. The microbes used were extracted from wood chips and soil. As pollutants limonene and α–pinene were used. Furthermore, it was investigated how the presence of silicone oil in the filter bed affected the filtering results. The filtering capacity in the non oil enriched filter was during the first 25days 10-12 g/m3h and thereafter some 15-20 g/m3h. The efficiency of the oil enriched filter was stable at 15-20 g/m3h.

The presence of off-flavor compounds in fish represents one of the significant economic problems encountered in aquaculture. These off-flavor compounds are due to the absorption of substances produced by microorganisms. Currently, a number of strategies have been employed to prevent or limit the growth of these microorganisms in recirculating aquaculture system. Therefore, it is important to evaluate the effectiveness of these strategies by monitoring the concentrations of off-flavor compounds in fish. In-vivo solid phase microextraction (SPME), a rapid and simple sample preparation method, allows the monitoring of concentrations of off-flavor compounds in live fish. In this research, geosmin and 2-methylisoborneol (2-MIB), which are produced by cyanobacteria and actinomycetes being the major sources for “earthy” and “muddy” flavors in fish, were selected as representatives. In order to accurately quantify these compounds in fish muscle, two kinetic calibration methods, on-fibre standardization and measurement using pre-determined extraction rate, were used. Results obtained were validated by traditional methods. The detection limit of in-vivo SPME in fish muscle was 0.12 ng/g for geosmin and 0.21 ng/g for 2-MIB, both below the human sensory threshold. Additionally, the binding effect of geosmin and 2-MIB in fish muscle was investigated in details. Facilitated by the agarose gel model, it was proven that binding did not impact the extraction rate under the pre-determined sampling time. Furthermore, an optional sampling position was undertaken by inserting the fibre into the fat tissue found under the fish belly, the results indicating that this method could decrease extraction time by up to two-thirds of its usual time.

<p>Utsläpp av lättflyktiga organiska föreningar (VOC) är ett växande mijlöproblem. Biofiltrering är ett relativt billigt sätt att rena luft förorenad med VOC. Biofiltrering har också en fördel i att föroreningen helt bryts ned och inte endast övergår i en annan form. Rapporten beskriver arbetet kring två biofilter av kolonntyp. Mikroberna som användes kom från främst träflis och jord. Som förorening användes limonen och α-pinen. Analys skedde med gaskromatografi.</p><p>Vidare undersöktes om närvaro av silikonolja i filterbädden påverkade resultatet Reningskapaciteten uppgick i filtret utan olja till ca 10 - 12 g/m3.h under de första 25 dagarna i drift och ökade därefter till ca 15 - 20 g/m3.h. Motsvarande data för det oljeberikade filtret är ca 15 - 20 g/m3.h i båda fallen</p> / <p>Emissions of volatile organic compounds are a growing environmental problem. Biofiltration is a relatively cost efficient method to purify air polluted with VOC:s. Biofiltraion also has the benefit of completely degrading the pollutants rather than just transferring them into another phase/form. This report describes the work on two biofilters of column type. The microbes used were extracted from wood chips and soil. As pollutants limonene and α–pinene were used.</p><p>Furthermore, it was investigated how the presence of silicone oil in the filter bed affected the filtering results. The filtering capacity in the non oil enriched filter was during the first 25days 10-12 g/m3h and thereafter some 15-20 g/m3h. The efficiency of the oil enriched filter was stable at 15-20 g/m3h.</p>