Foi desenvolvido um método para determinar canabinóides (canabidiol, canabinol e delta-9-tetraidrocanabinol) no cabelo. Uma amostra de 10mg foi descontaminada com diclorometano, seguida de digestão alcalina, microextração em fase sólida por headspace (HS-SPME) e analisada por espectrometria de massa associada à cromatografia em fase gasosa (GC/MS). Os limites de detecção e de quantificação foram de 0,07 e 0,12 ng/mg, respectivamente, para todos canabinóides estudados. O método demonstrou ser simples, rápido, preciso e linear no intervalo de 0,12 a 12 ng/mg (r2 > 0,98). Amostras de cabelo de 8 usuários de Cannabis foram coletadas de pacientes provenientes de uma clínica dependentes pela equipe médica. O método mostrou-se eficiente em amostras de cabelos de usuários que faziam uso da droga pelo menos 10 vezes por semana. / A method was to develop to detect cannabinoids (cannabidiol, cannabinol and delta-9-tetrahydrocannabinol) in hair. A 10 mg of hair sample was descontaminated by dichloromethane followed by alkalin digestion, headspace solid-phase microextraction technique (HS-SPME) and analyzed by gas chromatography-mass spectrometry (CG/MS). The detection and quantitation limits were 0,07 and 0,12ng/mg respectively for all studied cannabinoids. The method proved to be simple, fast, precise and linear at the range of 0,12 to 12ng/mg (r2 > 0,98). Eight hair samples of Cannabis user were collected from patients at admittance from a dependence clinic by clinical staff. The method showed efficient in samples of users who use the drug at least 10 fold a week.

<p>Different sample preparation steps prior to a detection method are often essential in analytical chemistry. In this thesis, both static extractions and on-line coupled solid-phase extractions have been studied in combination with different detection techniques. Aspects of performing sample preparations in miniaturized analytical devices and the development of poly(dimethylsiloxane) (PDMS) microchips are discussed. Polypyrrole was also evaluated as an electrochemically controllable stationary phase for solid-phase microextraction (SPME) and solid-phase extraction (SPE).</p><p>The first part of this thesis describes the extraction of an organic compound from a very complex solid matrix utilizing the pressurized-fluid extraction (PFE) technique. The presented results show that PFE is easily optimized and enables rapid extractions and extracts relatively free from interferences.</p><p>An integrated three-electrode device, which enabled electrochemical (EC) SPME under potential control, was developed. With this device, both anions and cations could be extracted employing two types of polypyrrole films. Planar micro band electrodes positioned at the end of a capillary were also used to electrochemically extract and detect anions in a miniaturized flow system. Different analyte concentrations and preconcentration times were examined, and good linear correlations were found between the extraction time and the detection response. The on-line coupling of a thin layer EC cell, with a polypyrrole coated working electrode, to different mass spectrometric (MS) techniques is also described and evaluated. The results show that EC-SPE, employing polypyrrole as stationary phase, can be used as a preconcentration step prior to detection.</p><p>In addition, this thesis describes the development and on-line coupling of a microelectrode array equipped PDMS microchip with an integrated graphite electrospray emitter to electrospray ionization (ESI) MS. The system enabled short transfer times and an EC conversion efficiency of 30% at a flow rate of 0.5 μL/min. The on-line EC/ESI-MS experiments were significantly simplified using a wireless Bluetooth battery-powered EC instrument.</p>

Different sample preparation steps prior to a detection method are often essential in analytical chemistry. In this thesis, both static extractions and on-line coupled solid-phase extractions have been studied in combination with different detection techniques. Aspects of performing sample preparations in miniaturized analytical devices and the development of poly(dimethylsiloxane) (PDMS) microchips are discussed. Polypyrrole was also evaluated as an electrochemically controllable stationary phase for solid-phase microextraction (SPME) and solid-phase extraction (SPE). The first part of this thesis describes the extraction of an organic compound from a very complex solid matrix utilizing the pressurized-fluid extraction (PFE) technique. The presented results show that PFE is easily optimized and enables rapid extractions and extracts relatively free from interferences. An integrated three-electrode device, which enabled electrochemical (EC) SPME under potential control, was developed. With this device, both anions and cations could be extracted employing two types of polypyrrole films. Planar micro band electrodes positioned at the end of a capillary were also used to electrochemically extract and detect anions in a miniaturized flow system. Different analyte concentrations and preconcentration times were examined, and good linear correlations were found between the extraction time and the detection response. The on-line coupling of a thin layer EC cell, with a polypyrrole coated working electrode, to different mass spectrometric (MS) techniques is also described and evaluated. The results show that EC-SPE, employing polypyrrole as stationary phase, can be used as a preconcentration step prior to detection. In addition, this thesis describes the development and on-line coupling of a microelectrode array equipped PDMS microchip with an integrated graphite electrospray emitter to electrospray ionization (ESI) MS. The system enabled short transfer times and an EC conversion efficiency of 30% at a flow rate of 0.5 μL/min. The on-line EC/ESI-MS experiments were significantly simplified using a wireless Bluetooth battery-powered EC instrument.

Calibration methods for quantitative on-site sampling using solid phase microextraction (SPME) were developed based on diffusion mass transfer theory. This was investigated using adsorptive polydimethylsiloxane/divinylbenzene (PDMS/DVB) and Carboxen/polydimethylsiloxane (CAR/PDMS) SPME fiber coatings with volatile aromatic hydrocarbons (BTEX: benzene, toluene, ethylbenzene, and o-xylene) as test analytes. Parameters that affected the extraction process (sampling time, analyte concentration, water velocity, and temperature) were investigated. Very short sampling times (10-300 s) and sorbents with a strong affinity and large capacity were used to ensure a 'zero sink' effect calibrate process. It was found that mass uptake of analyte changed linearly with concentration. Increase of water velocity increased mass uptake, though the increase is not linear. Temperature did not affect mass uptake significantly under typical field sampling conditions. To further describe rapid SPME analysis of aqueous samples, a new model translated from heat transfer to a circular cylinder in cross flow was used. An empirical correlation to this model was used to predict the mass transfer coefficient. Findings indicated that the predicted mass uptake compared well with experimental mass uptake. The new model also predicted rapid air sampling accurately. To further integrate the sampling and analysis processes, especially for on-site or <i>in-vivo</i> investigations where the composition of the sample matrix is very complicated and/or agitation of the sample matrix is variable or unknown, a new approach for calibration was developed. This involved the loading internal standards onto the extraction fiber prior to the extraction step. During sampling, the standard partially desorbs into the sample matrix and the rate at which this process occurs, was for calibration. The kinetics of the absorption/desorption was investigated, and the isotropy of the two processes was demonstrated, thus validating this approach for calibration. A modified SPME device was used as a passive sampler to determine the time-weighted average (TWA) concentration of volatile organic compounds (VOCs) in air. The sampler collects the VOCs by the mechanism of molecular diffusion and sorption on to a coated fiber as collection medium. This process was shown to be described by Fick's first law of diffusion, whereby the amount of analyte accumulated over time enable measurement of the TWA concentration to which the sampler was exposed. TWA passive sampling with a SPME device was shown to be almost independent of face velocity, and to be more tolerant of high and low analyte concentrations and long and short sampling times, because of the ease with which the diffusional path length could be changed. Environmental conditions (temperature, pressure, relative humidity, and ozone) had little or no effect on sampling rate. When the SPME device was tested in the field and the results compared with those from National Institute of Occupational Health and Safety (NIOSH) method 1501 good agreement was obtained. To facilitate the use of SPME for field sampling, a new field sampler was designed and tested. The sampler was versatile and user-friendly. The SPME fiber can be positioned precisely inside the needle for TWA sampling, or exposed completely outside the needle for rapid sampling. The needle is protected within a shield at all times hereby eliminating the risk of operator injury and fiber damage. A replaceable Teflon cap is used to seal the needle to preserve sample integrity. Factors that affect the preservation of sample integrity (sorbent efficiency, temperature, and sealing materials) were studied. The use of a highly efficient sorbent is recommended as the first choice for the preservation of sample integrity. Teflon was a good material for sealing the fiber needle, had little memory effect, and could be used repeatedly. To address adsorption of high boiling point compounds on fiber needles, several kinds of deactivated needles were evaluated. RSC-2 blue fiber needles were the more effective. A preliminary field sampling investigation demonstrated the validity of the new SPME device for field applications.

Calibration methods for quantitative on-site sampling using solid phase microextraction (SPME) were developed based on diffusion mass transfer theory. This was investigated using adsorptive polydimethylsiloxane/divinylbenzene (PDMS/DVB) and Carboxen/polydimethylsiloxane (CAR/PDMS) SPME fiber coatings with volatile aromatic hydrocarbons (BTEX: benzene, toluene, ethylbenzene, and o-xylene) as test analytes. Parameters that affected the extraction process (sampling time, analyte concentration, water velocity, and temperature) were investigated. Very short sampling times (10-300 s) and sorbents with a strong affinity and large capacity were used to ensure a 'zero sink' effect calibrate process. It was found that mass uptake of analyte changed linearly with concentration. Increase of water velocity increased mass uptake, though the increase is not linear. Temperature did not affect mass uptake significantly under typical field sampling conditions. To further describe rapid SPME analysis of aqueous samples, a new model translated from heat transfer to a circular cylinder in cross flow was used. An empirical correlation to this model was used to predict the mass transfer coefficient. Findings indicated that the predicted mass uptake compared well with experimental mass uptake. The new model also predicted rapid air sampling accurately. To further integrate the sampling and analysis processes, especially for on-site or <i>in-vivo</i> investigations where the composition of the sample matrix is very complicated and/or agitation of the sample matrix is variable or unknown, a new approach for calibration was developed. This involved the loading internal standards onto the extraction fiber prior to the extraction step. During sampling, the standard partially desorbs into the sample matrix and the rate at which this process occurs, was for calibration. The kinetics of the absorption/desorption was investigated, and the isotropy of the two processes was demonstrated, thus validating this approach for calibration. A modified SPME device was used as a passive sampler to determine the time-weighted average (TWA) concentration of volatile organic compounds (VOCs) in air. The sampler collects the VOCs by the mechanism of molecular diffusion and sorption on to a coated fiber as collection medium. This process was shown to be described by Fick's first law of diffusion, whereby the amount of analyte accumulated over time enable measurement of the TWA concentration to which the sampler was exposed. TWA passive sampling with a SPME device was shown to be almost independent of face velocity, and to be more tolerant of high and low analyte concentrations and long and short sampling times, because of the ease with which the diffusional path length could be changed. Environmental conditions (temperature, pressure, relative humidity, and ozone) had little or no effect on sampling rate. When the SPME device was tested in the field and the results compared with those from National Institute of Occupational Health and Safety (NIOSH) method 1501 good agreement was obtained. To facilitate the use of SPME for field sampling, a new field sampler was designed and tested. The sampler was versatile and user-friendly. The SPME fiber can be positioned precisely inside the needle for TWA sampling, or exposed completely outside the needle for rapid sampling. The needle is protected within a shield at all times hereby eliminating the risk of operator injury and fiber damage. A replaceable Teflon cap is used to seal the needle to preserve sample integrity. Factors that affect the preservation of sample integrity (sorbent efficiency, temperature, and sealing materials) were studied. The use of a highly efficient sorbent is recommended as the first choice for the preservation of sample integrity. Teflon was a good material for sealing the fiber needle, had little memory effect, and could be used repeatedly. To address adsorption of high boiling point compounds on fiber needles, several kinds of deactivated needles were evaluated. RSC-2 blue fiber needles were the more effective. A preliminary field sampling investigation demonstrated the validity of the new SPME device for field applications.

Polycyclic aromatic hydrocarbons (PAHs) and nitrogen-containing polycyclic aromatic compound (N-PAC) are widespread toxic pollutants in environments. The fate of PAHs and N-PACs are of great concern because some of these compounds were identified as caricinogenic, mutagenic and teratogenic compounds. As described in literature, dissolved organic matter (DOM) is an important factor in control of their fate; however, the binding behaviors between these compounds and DOM are still not fully understood. The binding constants (KDOC) between humic substances and one selected N-PAC, benzo[h]quinoline, were measured at varying pH levels using fluorescence quenching (FQ) method. As fluorescence characteristics of benzo[h]quinoline change with pH, determination required two optimum sets of excitation and emission wavelength pairs. A simple mixing model was proposed and used to eliminate the inherent fluorescence interference between benzo[h]quinoline (BQ) and its protonated form, benzo[h]quinolinium (BQH+), and to deduce Kmix which represents the overall binding as the sum of that for the individual analogs. The characteristics of humic substances, especially their hydrophobicity and aromaticity, established by principal components analysis of structural and elemental compositions, were the main determinants of their binding affinity with both benzo[h]quinoline and benzo[h]quinolinium (KBQ and KBQH+) across a range of pH values. Hydrophobic interaction is likely to control the binding between humic substance and benzo[h]quinoline and benzo[h]quinolinium, in lower and higher pH ranges (pH<3, pH>6). In contrast, cation exchange seems to control on the binding affinity of benzo[h]quinolinium in the middle range of pH. Determination of PAH concentration is quite essential for investigating the fate of PAHs in environments. Microwave-assisted headspace solid-phase microextraction (MA-HS-SPME) with a polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber was applied as a single step prior to determination of PAH concentrations in water using GC-MS. To optimize the extraction efficiency of PAHs by MA-HS-SPME, the influence of various parameters, including temperature, duration of thermal desorption, microwave irradiation power and duration, and the temperature of the circulating cooling water system, was studied. The proposed method was demonstrated applicable to environmental water samples. In addition, DOM matrix effect did not influence the determination and extraction efficiency of PAHs. Although the proposed simple mixing model can eliminate the fluorescent interference of hydrophobic organic compounds with acid-base pair forms, it is still limited in using for correcting the KDOC measurement of more than two fluorescent compounds simultaneously. A new alternative protocol, complexation-flocculation combined with MA-HS-SPME/GC-MS method, was proposed to determine the binding constants of seleted PAHs to humic substances. The results obtained are comparable with KDOC data reported in literatures. CF-MA-HS-SPME/GC-MS provides some advantages over other methods, such as applicable not limited to fluorescent compounds, faster in determination and capable in measuring varieties of compounds simultaneously.

No description available.

New solid phase microextraction (SPME) method was developed for brain tissue bioanalysis on a liquid chromatography mass spectrometry platform. To achieve set objectives, in vivo SPME desorption process was optimized for high throughput analysis through the development of a desorption device. Subsequently, new SPME coatings were developed for the extraction of polar neurotransmitters from biological matrices. In a targeted analysis, in vivo SPME was used to monitor of changes in the concentrations of endogenous compounds (multiple neurotransmitters) and exogenous drugs (carbamazepine and cimetidine) in the striatum of the rat brain extracellular fluid. For the first time, SPME was used for quantitative analysis of neurotransmitters and also study spacial distribution of other drugs in different regions of the brain extracellular fluid. A new approach was developed for improved metabolites coverage in a global non-targeted metabolomics studies. The proposed in vivo method showed how complementary results can be obtained through the combination of microdialysis and SPME for simultaneous sampling of the brain extracellular fluid. Finally, in a clinical application, SPME was used to monitor changes in the concentration of multiple neurotransmitters during deep brain stimulation of the pre-frontal cortex of the brain.

A new technique for sample preparation and trace analysis of organic pollutants in water using mixed-phase thin film (MPTF) devices, combined with direct thermal desorption, cold trapping, gas chromatography-mass spectrometry (GC-MS) is presented for the first time. Two novel analytical devices, Carboxen/polydimethylsiloxane (CAR/PDMS) and polydimethylsiloxane/divinylbenzene (PDMS/DVB) TF samplers were fabricated using spin coating technique and glass wool fabric mesh as substrate. The samplers were easily tailored in size and shape by cutting tools. Good durability and flat-shape stability were observed during extractions and stirring in water. The latter characteristic obviates the need for an extra framed holder for rapid thin film microextraction (TFME) and makes the samplers more robust and user-friendly. The analytical performance of the MPTF devices was satisfactorily illustrated and compared with those of solid phase microextraction (SPME) fibers and PDMS thin film membrane using water samples spiked with seven N–nitrosamines (NAs), known as disinfection by-products (DBPs) in drinking water. Marked enhancement of extraction efficiencies (typically more than one order of magnitude) for the N-nitrosamines, including the hydrophilic ones, was obtained with the MPTF devices under generally pre-equilibrium conditions, compared to the SPME fibers and PDMS thin film membrane. The analytical results obtained in this study, including linearity, repeatability and detection levels at low ng/L for the tested compounds, indicate that the new thin film devices are promising for rapid sampling and sample preparation of trace levels of polar organic pollutants in water with sensitivities higher than SPME fibers and with a wide application range typical of mixed-phase coatings. The user-friendly format and robustness of the novel devices are also advantageous for on-site applications, which is the ultimate use of thin film samplers. Moreover, the thin film fabrication approach developed in this study offers the possibility of making other novel samplers with PDMS or different absorptive polymers such as polyacrylate (PA) and polyethylene glycol (PEG) as particle-free, or as particle-loaded thin films with a variety of adsorptive solid particles. In another development in the course of this research, the performance and accuracy of the SPME fiber approach for sample preparation of selected DBPs were demonstrated and compared with the conventional liquid-liquid extraction (LLE) method by real drinking water samples analysis in collaboration with Health Canada. Four regulated trihalomethanes (THMs) and seven other DBPs known as priority by-products, including four haloacetonitriles, two haloketones and chloropicrin, were analyzed in real samples during two separate comparative studies. In each study, duplicate samples from several water treatment and distribution systems in Canada, collected and stabilized under the same protocol, were analyzed in parallel by two independent labs; in the University of Waterloo by an optimized headspace SPME-GC-MS and in Health Canada by a LLE-GC-ECD (electron capture detection) method equivalent to EPA 551.1. The values for the concentration of the analytes in the samples obtained by the two methods were in good agreement with each other in majority of the cases indicating that SPME affords the promise of a dependable sample preparation technique for rapid DBPs analysis. In particular, it was shown that the SPME fiber approach combined with GC-MS is a fast reliable alternative to the LLE-GC-ECD (EPA 551.1) method for analysis of the regulated THMs in the concentration ranges that are typical and relevant for drinking water samples.

O objetivo do presente trabalho foi desenvolver e validar um método analítico empregando microextração em fase sólida (SPME) para detecção e quantificação de isoflurano (ISO) na forma volátil e incluso em nanoemulsões intravenosas e, ainda, avaliar o efeito biológico destas. A detecção do ISO foi realizada através de cromatografia em fase gasosa com detector de ionização de chama (CG/DIC). As condições ideais para realização da pré-concentração e extração de ISO através da técnica de SPME foram temperatura ambiente, agitação constante, 30 min de extração e 2 min de dessorção no injetor do CG. O método desenvolvido foi validado avaliando os parâmetros de especificidade, linearidade, limites de detecção e quantificação, precisão, exatidão e robustez. As nanoemulsões contendo ISO foram desenvolvidas através da homogeneização à alta pressão, e apresentaram diâmetro médio, índice de polidispersão, potencial zeta e pH de 150 ± 0,78 nm, 0,08 ± 0,01, - 18 ± 2,4 mV e 6,03 ± 0,04, respectivamente. O pH foi ajustado para 7,4 (valor fisiológico). O teor de ISO nas formulações foi de 98,4 %. Não houve modificação das características físico-químicas das nanoemulsões após 30 dias de armazenamento a 8 ºC. Análises de espalhamento de luz múltiplo não demonstraram tendência a fenômenos de instabilidade física para as formulações. Os estudos do efeito anestésico das nanoemulsões intravenosas contendo ISO em cães evidenciaram uma redução significativa (p < 0,05) na dose comparada com a administração de ISO volátil. Não houve alterações no débito cardíaco, saturação de oxigênio na hemoglobina e nos biomarcadores das funções renal, hepática e muscular. Uma queda na pressão arterial dos cães foi observada em todos os tratamentos devido ao efeito hipotensor do ISO. Após administração das nanoemulsões contendo ISO e branca, observou-se taquipnéia, edema, eritema, e baixas concentrações de dióxido de carbono expiradas. Assim, a nanoemulsificação do ISO foi realizada com sucesso e a aplicação na anestesia geral intravenosa foi demonstrada. / The aims of this work were to develop and validate an analytical method using solidphase microextraction (SPME) to detect and quantify isoflurane (ISO) inhalation liquid and loaded in intravenous nanoemulsions, and also evaluate the biological effect of the formulations. ISO detection was made by gas chromatography with flame ionization detector (GC/FID). The ideal conditions setting for the pre concentration and extraction of ISO through SPME were environmental temperature, constant stirring, 30 min for extraction and 2 min for analyte desorption in the GC inlet port. The developed method was validated by means of specificity, linearity, detection and quantification limits, precision, accuracy and robustness. The ISOloaded nanoemulsions were formulated by high-pressure homogenization, and presented average diameter, polydispersity index, zeta potential and pH of 150 ± 0.78 nm, 0.08 ± 0.01, -18 ± 2.4 mV and 6.03 ± 0.04, respectively. The pH was adjusted to 7.4 (physiological value). The drug content on the formulations was 98.4 %. After 30 days of storage at 8 ºC no changes on nanoemulsion’s physicalchemical characteristics were observed. Multiple light scattering analysis did not demonstrate any physical destabilization phenomena for the formulations. The anesthetic effect study for the intravenous ISO-loaded nanoemulsions in dogs highlighted a significant reduction (p < 0.05) in dosage regimen when compared to the volatile ISO administration. There were no alterations on cardiac rate, oxygen hemoglobin saturation and on biomarkers of the renal, hepatic and muscle functionalities. A decrease in dog’s arterial blood pressure in all treatments due the hypotensive effect caused by ISO was observed. After the administration of the nanomulsions, ISO-loaded and unloaded, occurred tachypnea, edema, erythema and low end tidal concentrations of carbon dioxide. Taking all above into account, the method was considered easy on execution and suitable for laboratory routines, the ISO nanoemulsification was made successfully and its application on general anesthesia was demonstrated.