microssomas hepático de humanos (HLMs) e biotransformação empregando fungos. Anteriormente aos estudos de biotransformação e metabolismo in vitro, todos os métodos propostos foram validados e os resultados corroboraram de acordo com os guiais oficiais. Inicialmente foi desenvolvido um método para determinação simultânea da OXC e os enantiômeros de seu metabólito em meio de cultura empregando a eletroforese capilar. A separação foi realizada utilizando como eletrólito de análise uma mistura da ?-ciclodextrina fosfatada (P-?-CD) 1% (m/v) como seletor quiral em solução tampão tris-fosfato 10 mmol L-1 pH 2,5. O comprimento efetivo do capilar foi 20 cm, a tensão aplicada foi de ?20 kV e a temperatura de análise foi de 15° C. Para esse método, nenhuma técnica miniaturizada de preparação de amostra foi efetiva na extração desses analitos do meio de cultura. Portanto, optou-se por utilizar extração líquidolíquido empregando metil-terc-butil éter como solvente extrator. Os estudos de biotransformação demonstraram enantiosseletividade na formação da licarbazepina (LIC) a partir da OXC para duas espécies de fungos. A espécie Glomerella cingulata (VA1), biotransformou com 100% de fração enantiomérica (fe) o enantiômero (S)-(+)- LIC enquanto que a espécie Beuveria bassiana (ATCC 7159) metabolizou com fe de 79% o enantiômero (S)-(+)-LIC. Um outro método empregando a eletroforese capilar também foi desenvolvido neste trabalho. Este novo método foi empregado para a análise enantiosseletiva dos metabólitos da diHTBZ após o procedimento de metabolismo in vitro empregando microssomas hepático de humanos para o fármaco TBZ e também foi utilizado para análise dos metabólitos diHTBZ após o procedimento de biotransformação da TBZ empregando fungos. Neste método de EC foi utilizada como eletrólito de análise a carboximetil-?-ciclodextrina (CM-?-CD) 1% (m/v) como seletor quiral adicionada em solução tampão tris-fosfato 80 mmol L-1 pH 2,5. O comprimento efetivo do capilar correspondeu a 20 cm e a tensão aplicada foi de +15 kV. A temperatura de análise foi de 15° C. Entre as técnicas miniaturizadas de preparação de amostras avaliadas para extração destes metabólitos diHTBZ tanto em meio microssomal quanto em meio de cultura líquido, a DLLME foi escolhida. Para tanto, utilizando a matriz de meio microssomal (para aplicação dos estudos de metabolismo in vitro da TBZ) foi empregado 75 ?L de diclorometano como solvente extrator e 150 ?L de acetona como solvente dispersor. Os estudos de metabolismo in vitro demonstraram que o perfil cinético do metabolismo da TBZ corresponde a um comportamento de inibição pelo substrato e trata-se de um metabolismo diastereo- e enantiosseletivo. Estes estudos também demonstraram que os enantiômeros dos diastereoisômeros diHTBZ foram catalisados principalmente pela CYP2C19 e o clearance predito sugere que o metabolismo pelo fígado é a principal via para a eliminação da TBZ. Já, nos estudos de biotransformação com fungos para a TBZ, o método por CE foi utilizado e, assim como para o meio microssomal, as técnicas de microextração foram avaliadas. Novamente, foi escolhida a técnica DLLME como técnica de extração, e também foi utilizado 75 ?L de diclorometano como solvente extrator e 150 ?L de acetona como solvente dispersor. Os estudos preliminares de biotransformação da TBZ demonstraram diastereoisomerismo para todos os fungos avaliados, e, adicionalmente, para algumas espécies de fungos, houve também enantiosseletividade na formação dos isômeros. O fungo Chaetomiun globusum (VR10) metabolizou ambos isômeros da diHTBZ, sendo que a produção dos metabólitos foi diastereosseletiva para a formação majoritária do estereoisômero trans-diHTBZ e enantiosseletividade somente na produção do estereoisômero cisdiHTBZ. As espécies Glomerella cingulata (VA1), Mucor rouxii, e Beuveria bassiana (ATCC 7159), metabolizaram diastereoisomericamente e também enantiosseletivamente ambos metabólitos da diHTBZ, sendo que o fungo da espécie Mucor rouxii apresentou um perfil de metabolização bem interessante, com a formação majoritária dos enantiômeros (E1) dos diastereoisômeros cis- e trans- e formação majoritária do metabólito trans-diHTBZ. Os resultados apresentados nesse trabalho demonstraram que somente a DLLME foi efetiva na extração da TBZ em meio microssomal e em meio de cultura. Para analitos com características bastante básicas, como é o caso da OXC, as demais técnicas de microextração avaliadas não foram eficientes nas condições de análise empregadas nesse estudo devido principalmente à dificuldade de manter estes analitos na forma molecular. Porém, a importância deste trabalho recai sobre os resultados obtidos a partir da aplicação dos estudos estereosseletivos de biotransformação com fungos de ambos os fármacos e, principalmente, nos resultados obtidos do metabolismo in vitro da TBZ que corroboram com dados in vivo da literatura e traz novas informações a respeito do metabolismo deste fármaco / Nowadays miniaturized extraction techniques are widely used in many sectors of analytical chemistry because they present several advantages such as: the ability to extract analytes in levels of trace employing minimal or none amounts of organic solvents; facility of automation and speed in the extraction procedure. New methodologies with the aim of producing pure enantiomers of drugs marketed as racemates are also very promising. In this context, this study aimed to evaluate the miniaturized sample preparation techniques, Solid Phase Microextraction (SPME), Hollow Fiber Liquid Phase Microextraction (HF-LPME) and Dispersive Liquid-Liquid Microextraction (DLLME) in extraction of drugs and their metabolites: oxcarbazepine (OXC) and tetrabenazine (TBZ) from complex matrices such as microsomal medium and liquid culture medium for subsequent application in stereoselective in vitro metabolism using human liver microsomes (HLMs) and in biotransformation studies employing fungi as catalytic agent. Prior to the biotransformation and the in vitro metabolism studies, all the proposed methods were validated and the results were in agreement with the official guidelines. Initially, an enantioselective capillary electrophoresis method was developed for the simultaneous determination of OXC and its metabolites in liquid culture medium. The chiral separation was carried out using phosphated ?-cyclodextrin (P-?-CD) 1% (w/v) as the chiral selector in tris-phosphate 10 mmol L-1 pH 2.5 buffer solution. The effective length of the capillary was 20 cm, the applied voltage was ?20 kV and the temperature of analysis was 15 °C. For this method, no miniaturized sample preparation technique was effective in extracting these analytes from the culture medium. Therefore, liquid-liquid extraction using methyl tert-butyl ether as solvent extractor as employed. The biotransformation studies showed enantioselectivity in the formation of licarbazepine (LIC) by two fungus species. The specie Glomerella cingulata (VA1) biotransformed OXC with 100% of enantiomeric fraction (EF) for the (S)-(+)-LIC enantiomer while the fungus Beuveria bassiana (ATCC 7159) metabolized with EF of 79% for the (S)-(+)-LIC enantiomer. Next, another method by capillary electrophoresis was also developed in this work. This new method was employed for the enantioselective analysis of diHTBZ metabolites after in vitro microsomal metabolism of the drug TBZ. Additionally, this method was used to analyze the diHTBZ metabolites after TBZ biotransformation by fungi. The chiral separation of diHTBZ metabolites was performed by using carboxymethyl-?-cyclodextrin (CM-?-CD) 1% (w/v) as the chiral selector added to trisphosphate buffer solution 80 mmol L-1 pH 2.5. The effective length of the capillary was 20 cm and the applied voltage was +15 kV. The analysis temperature was 15 °C. Among the miniaturized sample preparation techniques evaluated for the extraction of diHTBZ metabolites from both matrices, human liver microsomal and in liquid culture medium, DLLME showed to be the most adequate. Therefore, using microsomal medium as matrix 75 ?L dichloromethane as solvent extractor and 150 ?L acetone as disperser solvent was used. The in vitro metabolism of TBZ showed a kinetic profile of inhibition by substrate and demonstrated a diastereo- and enantioselective metabolism. These studies showed also that the enantiomers of the diastereomers of the diHTBZ were catalyzed mainly by CYP2C19 and the predicted clearance suggests that the metabolism by the liver is the major pathway for the elimination of TBZ. For the last, for fungal biotransformation studies with TBZ, 75 ?L was used as extracting solvent of dichloromethane and 150 ?L acetone as solvent disperser for the DDLME procedure. Preliminary biotransformation studies TBZ demonstrated a diastereoisomerism for all evaluated fungi, and additionally for some species of fungi, showed enantioselectivity in the formation of isomers. The fungus Chaetomiun globusum (VR10) metabolized both isomers of diHTBZ, and the production of metabolites was diastereoselective with majority formation of the trans-stereoisomer diHTBZ and enantioselectivity only in the production of cis-stereoisomer diHTBZ. The species Glomerella cingulata (VA1), Mucor rouxii, and Beuveria bassiana (ATCC 7159), metabolized diastereomerically and also enantiosselectivelly both metabolites of diHTBZ. The fungus Mucor rouxii showed an interesting biotransformation profile, with the majority training enantiomers (E1) of cis- and trans- diastereoisomers and majority formation of trans-diHTBZ metabolite. The results presented in this study showed that only DLLME was effective in extracting the TBZ from microsomal and liquid culture medium. For analytes with very basic features such as the OXC, the other evaluated microextraction techniques were not effective under the conditions employed in this study due mainly to the difficulty of keeping these analytes in the molecular form.

Técnicas modernas de preparo de amostra têm sido utilizadas na determinação de diferentes classes de compostos em diversos tipos de matrizes. Essas técnicas podem ser divididas em dois grandes grupos, as baseadas em solvente e as baseadas sorvente, foco do trabalho. Dentre os materiais sorventes mais estudados atualmente, os derivados de grafeno têm se destacado devido a suas propriedades físico-químicas favoráveis para realizar sorção com uma grande variedade de compostos de interesse. Por isso, no presente trabalho são apresentadas possibilidades de utilização de materiais baseados em grafeno nas seguintes técnicas de preparo de amostras: microextração por sorvente empacotado (MEPS), extração \"\"on-line\"\" e extração sortiva em barra de agitação (SBSE). Para a técnica MEPS, foi realizado a síntese de óxido de grafeno e grafeno suportados por ligação covalente em aminopripil sílica. Esses materiais foram empregados como sorventes para determinação de parabenos em amostras de água. O método desenvolvido apresentou limites de quantificação (LOQ) que variaram de <a name=\"_Hlk498351551\">0,2 a 0,3 &mu;g/L, coeficientes de variação (CV) &lt; 19,2% e exatidão de 82,3 a 119,2%. Os materiais utilizados na técnica MEPS também foram utilizados para empacotar colunas de extração \"on-line\" e realizar uma comparação entre as fases sintetizadas. O método de extração \"on-line\" apresentou LOQ de 0,5 &mu;g/L, exatidão de 88,2 à 107,2 e CV &lt; 16%. A comparação entre as colunas de extração empacotadas com o grafeno e seu óxido suportados na aminopropil sílica mostrou que o grafeno suportado na sílica apresenta maior retenção para os parabenos mais apolares. Com relação ao desenvolvimento de barras de SBSE revestidas com grafeno, o método desenvolvido empregando as barras de SBSE apresentou valores de LOQ que variaram de 2 à 8 &mu;g/L, exatidão de 81,9 à 126,3% e CV &lt; 30%. Além disso, avaliou-se o uso do grafeno e óxido de grafeno ligado a sílica com grupamentos amino variando algumas condições de síntese e testando esses materiais para analitos das classes das triazinas, sulfonamidas e anti-inflamatórios não esteroidais. Também são apresentados testes iniciais realizados para um novo modo de extração proposto, similar a técnica SBSE, avaliando a extração de parabenos e anti-inflamatórios não esteroidais. / Modern sample preparation techniques have been applied to the determination of different compounds class in several matrices. These techniques might be divided into two groups, solvent and sorbent based, the last being the goal of this work. Nowadays, among the most studied materials the graphene based ones has been highlighted due to its physical chemical properties favorable to sorption process of a variety of interested compounds. The present work shows possibilities to employ graphene based materials in the follow sample preparation techniques: microextraction by packed sorbent (MEPS), \"on-line\" extraction, and stir bar sorptive extraction (SBSE). For MEPS, the materials graphene oxide and graphene supported on aminopropyl silica through covalent bounds were synthesized. These materials were employed as sorbent to determine parabens in water samples. The developed method showed limits of quantification (LOQ) ranging from 0,2 a 0,3 &mu;g/L, coefficients of variation (CV) &lt; 19,2% and accuracy ranging from 82,3 à 119,2%. The synthetized materials used in MEPS were also used and compared to an \"on-line\" method employing an extraction column packed with them. The \"on-line\" method showed LOQ of 0,5 &mu;g/L, accuracy ranging from 88,2 to 107,2 and CV &lt; 16%. The comparison between packed column with graphene and graphene oxide supported on aminopropyl silica showed that graphene had a higher retention for parabens with high Log Kow. The method developed with SBSE bars coated with graphene showed LOQ ranging from 2 to 8 &mu;g/L, accuracy ranging from 81,9 to 126,3% and CV &lt; 30%. Moreover, the employment of graphene oxide and graphene synthetized by changing some synthesis conditions and testing these materials to extract triazines, sulfonamides, and non-steroidal anti-inflammatory drugs was also evaluated. In addition, are presented the preliminary tests regarding to a new extraction mode, similar to SBSE. These tests were done for parabens and non-steroidal anti-inflammatory drugs.

The primary focus of my work has been to prepare new solid adsorbents for solid phase microextraction (SPME) via sputtering of silicon. The orientation of the silica substrates/fibers and the sputtering pressure induced the formation of porous and columnar structures. Sputtering was performed for different times to yield fibers with different thicknesses. Piranha treatment of the surface increased the concentration of silanol groups, which underwent condensation with vapor deposited octadecyldimethylmonomethoxy silane to incorporate octadecyl chains onto the fiber surfaces. Silanized, sputtered fibers were preconditioned for 3 h at 320 °C to remove the unreacted chains. Comparison of the extraction efficiencies of 1.0 and 2.0 µm sputtered, silanized fibers with a commercial fiber (7 µm PDMS) for a series of analyte mixtures, which included alkanes, alcohols, aldehydes, esters, and amines, was demonstrated. The silanized, sputtered fiber performed better than the commercial fiber in extraction of most of the compounds. These fibers demonstrated long life as no degradation was seen even after 300 extractions. Carry-over between runs was not observed. The repeatability of the sputtered fibers was similar to commercial ones. The extraction of more than 50 compounds from a real world botanical sample using the 2.0 µm sputtered, silanized fiber was also demonstrated. In my second project, a facile method for the preparation of superhydrophobic surfaces (SHS) on glass and silicon surfaces was developed. A two-tier topography (needed for an SHS) was created in 60 min by the aggregation of nanosilica during in situ urea-formaldehyde polymerization. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) demonstrated rough topography. Vapor deposition of a low surface energy silane imparted hydrophobicity, which was confirmed by the presence of an F 1s signal in X-ray photoelectron spectroscopy (XPS). The prepared surfaces exhibited water contact angles (WCA) of greater than 150 °C with very low sliding angles. In my third project, a multilayer assembly of nitrilotris(methylene)triphosphonic acid, a corrosion inhibitor, and zirconium was constructed on alumina at room temperature. Attempts to prepare a layer-by-layer assembly at higher temperature (70 °C) was unsuccessful due to etching of the alumina surface. A suite of analytical techniques, XPS, AFM, time-of-flight secondary ion mass spectrometry, and spectroscopic ellipsometry was used to characterize these surfaces. This thesis also contains appendices of tutorial articles I wrote on modeling in ellipsometry, and data analysis tools (classical least squares and multivariate curve resolution).

Whey protein isolate (WPI) contains at least 90% protein and should ideally possess a bland flavor without typical dairy flavors including sweet aromatic and cooked/milky notes. However, its flavor may be highly variable due to factors including original whey source, processing and storage conditions. Novel technologies removing nonpolar compounds responsible for off-flavors and off-flavor formations are desirable. The major objective of this research was to evaluate impacts of supercritical carbon dioxide (scCO2) extraction, a known green process, on volatile profiles of WPI. A prior sub-objective was to establish an analytical technique for characterization of volatiles. Specifically, adsorption conditions in a well-established head-space solid-phase microextraction (SPME) method were used for quick and reliable assays of volatiles in WPI, using a divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber. The adsorption of volatiles on the SPME fiber was studied at 21, 40 or 50 °C, each with durations of 5, 15 and 20 min, and analyzed by GC/MS. Based on the number of GC/MS peaks and the corresponding peak areas, adsorption conditions of 50 °C for 20 min were selected for subsequent studies. In the second sub-objective, GC/MS profiles of WPI were characterized after scCO2 extraction using a continuous stream of CO2 at 50 g/min, controlled at various combinations of temperature (30-65°C), pressure (7.0-30.0 MPa), and duration (10-90 min). Extractions with a higher temperature and a higher pressure for a longer time were generally more effective in removing volatiles, and most peaks on the chromatogram of the unprocessed WPI sample disappeared or were reduced very significantly after all studied extraction conditions, even at subcritical conditions of 7.0 MPa and 30 °C for 1 hour. Our findings demonstrated that supercritical or subcritical CO2 may provide a green approach to reduce volatiles in whey protein preparations for novel food applications.

Aldehydes in lung cancer cell culture have been investigated using gas chromatography/mass spectrometry and solid-phase microextraction with on-fiber derivatization. In this study, the poly(dimethylsiloxane/divinylbenzene (PDMS/DVB) fiber was used and o-2,3,4,5,6-(pentafluorobenzyl) hydroxylamine hydrochloride (PFBHA) was first loaded on the fiber. Aldehydes in the headspace of lung cancer cell culture were extracted by solid-phase microextraction (SPME) fiber and subsequently derivatized by PFBHA on the fiber. Finally, the aldehyde oximes formed on the fiber were analyzed by gas chromatography/mass spectrometry (GC/MS). Using this method, acetaldehyde decrease was found in both non-small lung cancer cell cultures studied compared to the medium control study. The results of spiking the cell culture with acetaldehyde solution showed that 5 million SK-MES-1 cell lines could consume up to 4.5 uM acetaldehyde in 15-ml medium, and 5 million NCI-H522 cell lines could consume 5.9 uM acetaldehyde in 15-ml medium. The decrease of acetaldehyde may contribute to the metabolism of lung cancer cells. It was proved that GC/MS and SPME with on-fiber derivatization is a simple, rapid, sensitive and solvent-free method for the detection of aldehydes in lung cancer cell culture.

Various needle trap devices (NTDs) with different designs for different applications have been developed during the past decade. A theoretical model on the fundamentals of the NTD was recently proposed, which employed the theory of frontal (gas-solid) chromatography to describe the sampling process, where a gaseous sample was continuously introduced into the sorbent bed. In this investigation, different types of sorbent particles with different dimensions were packed into the needle as adsorbents. The effect of particle dimension, which would affect the packing density and consequently the capacity, the extraction efficiency, and desorption efficiency of the NTD were experimentally investigated and the proposed theory was validated. The results demonstrated that NTDs packed with small particles possess higher extraction capacity and efficiency but much higher resistance to flow as well. The higher resistance did not necessarily result in poor desorption efficiency, because desorption efficiency was affected by both the sorbent bed structure and the desorption gas flow. The relationships observed among those physical parameters provide valuable guidance on how to design an NTD with high performance potential for future applications. For particulate sampling, it was found that NTDs packed with different particles presented high collection efficiency of the particulates being investigated, and the collection efficiency was dominated by the pore size and distribution of the sorbent bed packed inside the needle. Collection efficiency also increased with increase in solidity of the sorbent bed; the increase in humidity of the aerosol sample; and the decrease of sampling rate. The results also provide valuable guidance on the optimisation of needle trap for particulate collection.

A cold fiber solid phase microextraction device was designed and constructed based on the use of a thermoelectric cooler (TEC). A three-stage thermoelectric cooler was used for cooling a copper rod coated with a polydimethylsiloxane (PDMS) hollow fiber, which served as the SPME fiber. The copper rod was mounted on a commercial SPME plunger and exposed to the cold surface of the TEC, which was enclosed in a small aluminum box. A heat sink and a fan dissipated the generated heat at the hot side of the TEC. By applying an appropriate DC voltage to the TEC, the upper part of the copper rod, which was in contact to the cold side of the TEC, was cooled and the hollow fiber reached a lower temperature through heat transfer. A thermocouple was embedded in the cold side of the TEC for indirect measurement of the fiber temperature. A portable cold fiber SPME device was made by using a car battery as the power supply. The cold fiber SPME device with thermoelectric cooling was applied in quantitative analysis of off-flavors in rice. Hexanal, nonanal, and undecanal were chosen as three test analytes in rice. These analytes were identified according to their retention times and analyzed with a GC/FID instrument. Headspace extraction conditions (i.e. extraction temperature and extraction time) were optimized. Standard addition calibration graphs were obtained at the optimized conditions and the concentrations of the three analytes were calculated. The developed method was compared to a conventional solvent extraction method. The applicability of the portable cold fiber SPME with TEC for field sampling was tested. The effect of cooling on extraction recovery and the reproducibility of extraction were examined for extractions from an n-alkane flow through system. It was found that the extraction recoveries were significantly higher when the fiber was cooled. To further investigate the effect of cooling on the sensitivity of SPME in field sampling, the portable cold fiber SPME was used for extraction of volatile components from living wisteria flowers. Both the number of identified compounds and the related peak areas increased for extractions with cold PDMS fiber relative to without cooling and commercial PDMS and PA fibers. The portable cold fiber SPME device was also used for field sampling of volatile components of living lily-of-the-valley flowers and the extracted compounds were analyzed with GC/MS. The desorption kinetics of hydrophobic organic compounds (HOCs) from environmental solid matrices was investigated using cold fiber SPME with CO2 cooling. Polycyclic aromatic hydrocarbons (PAHs) and selected volatile organic compounds (i.e. toluene, ethylbenzene, o-xylene) were used as test analytes. Sand, silica gel, and clay were used as laboratory model solid matrices and were contaminated by the test analytes. Certified sediments were used as naturally contaminated samples. In this approach, the organic compounds, released from contaminated solid samples at different elevated temperatures, were exhaustively extracted with cold fiber SPME over different extraction times. The extraction data were used to obtain desorption and Arrhenius plots. The rate constants of desorption and activation energies of desorption were measured for each contaminant using these plots. The results were comparable to those reported in the literature.

The use of laser desorption as a sample introduction method for solid phase microextraction (SPME) has been investigated in this research project. Three different types of analytical instruments, mass spectrometry (MS), ion mobility spectrometry (IMS) and gas chromatography (GC) were employed as detectors. The coupling of laser desorption SPME to these three instruments was constructed and described in here. <br /><br /> Solid phase microextraction/surface enhanced laser desorption ionization fibers (SPME/SELDI) were developed and have been coupled to two IMS devices. SPME/SELDI combines sampling, sample preparation and sample introduction with the ionization and desorption of the analytes. Other than being the extraction phase for the SPME fiber, the electro-conductive polymer coatings can facilitate the ionization process without the involvement of a matrix assisted laser desorption/ionization (MALDI) matrix. The performance of the SPME coatings and the experimental parameters for laser desorption SPME were investigated with the SPME/SELDI IMS devices. The new SPME/SELDI-IMS 400B device has a faster data acquisition system and a more powerful data analysis program. The optimum laser operation parameters were 250 <em>&mu;J</em> laser energy and 20 <em>Hz</em> repetition rate. Three new SPME coatings, polypyrrole (PPY), polythiophene (PTH) and polyaniline (PAN) were developed and evaluated by an IMS and a GC. The PPY coating was found to have the best performance and was used in most of the experiments. The characteristics of the PPY and the PTH SPME/SELDI fiber were then assessed with both IMS and MS. Good linearity could be observed between the fiber surface area and the signal intensity, and between the concentration and the signal intensities. <br /><br /> The ionization mechanism of poly(ethylene glycol) 400 (PEG) was studied with the SPME/SELDI-IMS 400B device. It was found that the potassiated ions and sodiated ions were both present in the ion mobility spectra. The results obtained with quadrupole time-of-flight (QTOF) MS confirmed the presence of both potassiated and sodiated ions. This result suggested that cationization is the main ionization process when polymers are directly ionized from the PPY coated silica surface. Four PEGs with different average molecular weights and poly(propylene glycol) 400 were also tested with this SPME/SELDI device. The differences between the ion mobility spectra of these polymers could be used for the fast identification of synthetic polymers. <br /><br /> The SPME/SELDI fibers were then coupled to QTOF MS and hybrid quadrupole linear ion trap (QqLIT) MS, respectively. Improved sensitivity could be achieved with QqLIT MS, as the modified AP MALDI source facilitated the ion transmission. The application of method for analysis of urine sample and the bovine serum albumin (BSA) digest were demonstrated with both PPY and PTH fibers. The LOD for leucine enkephalin in urine was determined to be 40 <em>fmol &mu;L^-1</em> with PTH coated fiber; and the LOD for the BSA digest was 2 <em>fmol &mu;L^-1</em> obtained with both PTH and PPY fibers. <br /><br /> A new multiplexed SPME/AP MALDI plate was designed and evaluated on the same QqLIT MS to improve the throughput, and the performance of this technique. The experimental parameters were optimized to obtain a significant improvement in performance. The incorporation of diluted matrix to the extraction solution improved the absolute signal and S/N ratio by 104X and 32X, respectively. The incorporation of reflection geometry for the laser illumination improved the S/N ratio by more than two orders of magnitude. The fully optimized high throughput SPME/AP MALDI configuration generated detection limit improvements on the order of 1000-7500X those achieved prior to these modifications. This system presents a possible alternative for qualitative proteomics and drug screening. <br /><br /> Laser desorption SPME as a sample introduction method for the fast analysis of non-volatile synthetic polymers was also demonstrated here. The coupling of laser desorption SPME to GC/FID and GC/MS was performed, and the advantage of laser desorption over traditional thermal desorption was demonstrated in this research. Laser desorption PEG 400 was observed more effcient than thermal desorption. Good separation was obtained even with a 1-m or 2-m column. These results demonstrate the potential of laser desorption SPME as a sample introduction method for the fast GC analysis of non-volatile compounds such as synthetic polymers.

A cold fiber solid phase microextraction device was designed and constructed based on the use of a thermoelectric cooler (TEC). A three-stage thermoelectric cooler was used for cooling a copper rod coated with a polydimethylsiloxane (PDMS) hollow fiber, which served as the SPME fiber. The copper rod was mounted on a commercial SPME plunger and exposed to the cold surface of the TEC, which was enclosed in a small aluminum box. A heat sink and a fan dissipated the generated heat at the hot side of the TEC. By applying an appropriate DC voltage to the TEC, the upper part of the copper rod, which was in contact to the cold side of the TEC, was cooled and the hollow fiber reached a lower temperature through heat transfer. A thermocouple was embedded in the cold side of the TEC for indirect measurement of the fiber temperature. A portable cold fiber SPME device was made by using a car battery as the power supply. The cold fiber SPME device with thermoelectric cooling was applied in quantitative analysis of off-flavors in rice. Hexanal, nonanal, and undecanal were chosen as three test analytes in rice. These analytes were identified according to their retention times and analyzed with a GC/FID instrument. Headspace extraction conditions (i.e. extraction temperature and extraction time) were optimized. Standard addition calibration graphs were obtained at the optimized conditions and the concentrations of the three analytes were calculated. The developed method was compared to a conventional solvent extraction method. The applicability of the portable cold fiber SPME with TEC for field sampling was tested. The effect of cooling on extraction recovery and the reproducibility of extraction were examined for extractions from an n-alkane flow through system. It was found that the extraction recoveries were significantly higher when the fiber was cooled. To further investigate the effect of cooling on the sensitivity of SPME in field sampling, the portable cold fiber SPME was used for extraction of volatile components from living wisteria flowers. Both the number of identified compounds and the related peak areas increased for extractions with cold PDMS fiber relative to without cooling and commercial PDMS and PA fibers. The portable cold fiber SPME device was also used for field sampling of volatile components of living lily-of-the-valley flowers and the extracted compounds were analyzed with GC/MS. The desorption kinetics of hydrophobic organic compounds (HOCs) from environmental solid matrices was investigated using cold fiber SPME with CO2 cooling. Polycyclic aromatic hydrocarbons (PAHs) and selected volatile organic compounds (i.e. toluene, ethylbenzene, o-xylene) were used as test analytes. Sand, silica gel, and clay were used as laboratory model solid matrices and were contaminated by the test analytes. Certified sediments were used as naturally contaminated samples. In this approach, the organic compounds, released from contaminated solid samples at different elevated temperatures, were exhaustively extracted with cold fiber SPME over different extraction times. The extraction data were used to obtain desorption and Arrhenius plots. The rate constants of desorption and activation energies of desorption were measured for each contaminant using these plots. The results were comparable to those reported in the literature.

The feasibility of using solid phase micro-extraction (SPME) as an in vivo sampling tool for analysis of trace environmental contaminants in fish exposed to municipal wastewater effluents (MWWEs) was validated using controlled laboratory and field experiments. SPME was compared with traditional extraction techniques， including solid phase extraction (SPE) in water and solid-liquid extraction (SLE) in fish tissues to assess relative efficiencies. All three techniques were used to quantify the presence of eight compounds of interest in fish exposed to MWWEs in the laboratory, as well as in wild and field caged fish upstream and downstream of three wastewater treatment plants in the Grand River watershed. Atrazine, carbamazepine, naproxen, diclofenac, gemfibrozil, bisphenol A, fluoxetine and ibuprofen were selected as target compounds due to their diverse chemical characteristics and frequent detection in surface waters and sediments around the world. The distribution coefficients between various sample matrices (water, fish) and extraction phases (SPME fibers) were compared, as were extraction profiles and bioconcentration factors of target analytes in muscle of fish exposed to MWWEs under laboratory conditions, during field caging studies, or collected (wild) from the Grand River. Poly(dimethylsiloxane) (PDMS) medical grade tubing was utilized as the SPME extraction phase, which when kinetically calibrated, were effective at extracting and quantifying the target analytes from both water and fish tissue relative to traditional techniques. Caged and in wild fish exposed to MWWEs from all three municipal treatment plants bio-accumulated detectable levels of several of the target chemicals. All target analytes (except for fluoxetine) were identified in the MWWEs and exposed fish by SPME at low concentrations (ng/L). The presence and concentration of the targeted analytes in both water and wild fish living in the Grand River watershed varied with season and proximity to the wastewater outfalls. Results demonstrate that properly applied SPME can detect and quantify selected contaminants in fish tissues, surface water, and wastewater effluents. In vivo SPME allows for non-lethal sampling of fish, which creates the opportunity for monitoring contaminant exposure in receiving environments influenced by MWWEs or non-point-source runoff while minimizing the impact on the organisms.