Solid phase microextraction (SPME) has been widely used in a variety of sample matrices and proven to be a simple, fast and solvent-free sample preparation technique. A challenging limitation in the further development of this technique has been the insufficient sensitivity for some trace applications. This limitation lies mainly in the small volume of the extraction phase. According to the fundamentals of SPME, different strategies can be employed to achieve higher sensitivity for SPME sampling. These include cooling down the extraction phase, preparing a high capacity particle-loading extraction phase, as well as using a thin film with high surface area-to-volume ratio as the extraction phase. In this thesis, four sampling approaches were developed for high sensitivity sampling by employing cold fiber, thin film, cooling membrane and particle loading membrane as sampling tools. These proposed methods were applied to liquid, solid and particularly trace gas analysis. First, a fully automated cold fiber device that improves the sensitivity of the technique by cooling down the extraction phase was developed. This device was coupled to a GERSTEL® MultiPurpose Sampler (MPS 2), and applied to the analysis of volatiles and semi-volatiles in aqueous and solid matrices. The proposed device was thoroughly evaluated for its extraction performance, robustness, reproducibility and reliability by gas chromatograph/mass spectrometer (GC/MS). The evaluation of the automated cold fiber device was carried out using a group of compounds characterized by different volatilities and polarities. Extraction efficiency and analytical figures of merit were compared to commercial SPME fibers. In the analysis of aqueous standard samples, the automated cold fiber device showed a significant improvement in extraction efficiency when compared to commercial polydimethylsiloxane (PDMS) and non-cooled cold fiber. This was achieved due to the low temperature of the coating during sampling. Results from the cold fiber and commercial divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber analysis of solid sample matrices were obtained and compared. Results demonstrated that the temperature gap between the sample matrix and the coating significantly improved the distribution coefficient, and consequently, the extraction amount. The newly automated cold fiber device presents a platform for headspace analysis of volatiles and semi-volatiles for a large number of samples, with improved throughput and sensitivity. Thin film microextraction (TFME) improves the sensitivity by employing a membrane with a high surface area-to-volume ratio as the extraction phase. In Chapter 3, a simple non-invasive sample preparation method using TFME is proposed for sampling volatile skin emissions. Evaluation experiments were conducted to test the reproducibility of the sampling device, the effect of the membrane size, and the method for storage. Results supported the reproducibility of multi-membrane sampling, and demonstrated that sampling efficiency can be improved using a larger membrane. However, ability to control the sampling environment and time was proved to be critical in order to obtain reliable information; the in vivo skin emission sampling was also influenced by skin metabolism and environmental conditions. Next, the method of storage was fully investigated for the membrane device before and after sampling. This investigation of storage permitted the sampling and instrument analysis to be conducted at different locations. Finally, the developed skin sampling device was applied in the identification of dietary biomarkers after garlic and alcohol ingestion. In this experiment, the previously reported potential biomarkers dimethyl sulphone, allyl methyl sulfide and allyl mercaptan were detected after garlic intake, and ethanol was detected after the ingestion of alcohol. Experiments were also conducted in the analysis of volatile organic compounds (VOCs) from upper back, forearm and back thigh of the body on the same individual. Results showed that 27 compounds can be detected from all of the 3 locations. However, these compounds were quantitatively different. In addition, sampling of the upper back, where the density of sebaceous glands is relatively high, detected more compounds than the other regions. In Chapter 4, a novel sample preparation method that combines the advantages of cold fiber and thin film was developed to achieve the high extraction efficiency necessary for high sensitivity gas sampling. A cooling sampling device was developed for the thin film microextraction. Method development for this sampling approach included evaluation of membrane temperature effect, membrane size effect, air flow rate and humidity effect. Results showed that high sensitivity for equilibrium sampling can be achieved by either cooling down the membrane and/or using a large volume extraction phase. On the other hand, for pre-equilibrium extraction, in which the extracted amount was mainly determined by membrane surface area and diffusion coefficient, high sensitivity was obtained by thin membranes with a large surface area and/or high sampling flow rate. In addition, humidity evaluations showed no significant effect on extraction efficiency due to the absorption property of the liquid extraction phase. Next, the limit of detection (LOD) and reproducibility of the developed cooling membrane gas sampling method were evaluated. LOD with a membrane radius of 1 cm at room temperature sampling were 9.24 ng/L, 0.12 ng/L, 0.10 ng/L for limonene, cinnamaldehyde and 2-pentadecanone, respectively. Intra- and inter-membrane sampling reproducibility had a relative standard deviation (RSD%) lower than 8% and 13%, respectively. Results uniformly demonstrated that the proposed cooling membrane device could serve as a powerful tool for gas in trace analysis. In Chapter 5, a particle-loading membrane was developed to combine advantages of high distribution coefficient and high surface area geometry, and applied in trace gas sampling. Bar coating, a simple and easy preparation method was applied in the preparation of the DVB/PDMS membrane. Membrane morphology, particle ratio, membrane size and extraction efficiency were fully evaluated for the prepared membrane. Results show that the DVB particles are uniformly distributed in the PDMS base. The addition of a DVB particle enhanced the stiffness of the membrane to some extent, and improved the extraction capacity of the membrane. Extraction capacity for benzene was enhanced by a factor of 100 when the membrane DVB particle ratio increased from 0% to 30%. Additionally, the prepared DVB/PDMS membrane provided higher extraction efficiency than pure PDMS membrane and DVB/PDMS fiber, especially for highly volatile and polar compounds. The high reproducibility of the prepared DVB/PDMS membrane in air sampling demonstrated the advantage of the bar coating preparation method, and also permitted quantitative analysis. Last, the prepared particle-loading membrane was applied to semi-quantitative and quantitative analysis of indoor and outdoor air, respectively. Both the equilibrium calibration method and diffusion-based calibration method were proposed for the quantitative analysis. Results showed that the high capacity particle-loading membrane can be used for monitoring trace analytes such as perfume components and air pollutants.

Solid phase microextraction (SPME) has been widely used in a variety of sample matrices and proven to be a simple, fast and solvent-free sample preparation technique. A challenging limitation in the further development of this technique has been the insufficient sensitivity for some trace applications. This limitation lies mainly in the small volume of the extraction phase. According to the fundamentals of SPME, different strategies can be employed to achieve higher sensitivity for SPME sampling. These include cooling down the extraction phase, preparing a high capacity particle-loading extraction phase, as well as using a thin film with high surface area-to-volume ratio as the extraction phase. In this thesis, four sampling approaches were developed for high sensitivity sampling by employing cold fiber, thin film, cooling membrane and particle loading membrane as sampling tools. These proposed methods were applied to liquid, solid and particularly trace gas analysis. First, a fully automated cold fiber device that improves the sensitivity of the technique by cooling down the extraction phase was developed. This device was coupled to a GERSTEL® MultiPurpose Sampler (MPS 2), and applied to the analysis of volatiles and semi-volatiles in aqueous and solid matrices. The proposed device was thoroughly evaluated for its extraction performance, robustness, reproducibility and reliability by gas chromatograph/mass spectrometer (GC/MS). The evaluation of the automated cold fiber device was carried out using a group of compounds characterized by different volatilities and polarities. Extraction efficiency and analytical figures of merit were compared to commercial SPME fibers. In the analysis of aqueous standard samples, the automated cold fiber device showed a significant improvement in extraction efficiency when compared to commercial polydimethylsiloxane (PDMS) and non-cooled cold fiber. This was achieved due to the low temperature of the coating during sampling. Results from the cold fiber and commercial divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber analysis of solid sample matrices were obtained and compared. Results demonstrated that the temperature gap between the sample matrix and the coating significantly improved the distribution coefficient, and consequently, the extraction amount. The newly automated cold fiber device presents a platform for headspace analysis of volatiles and semi-volatiles for a large number of samples, with improved throughput and sensitivity. Thin film microextraction (TFME) improves the sensitivity by employing a membrane with a high surface area-to-volume ratio as the extraction phase. In Chapter 3, a simple non-invasive sample preparation method using TFME is proposed for sampling volatile skin emissions. Evaluation experiments were conducted to test the reproducibility of the sampling device, the effect of the membrane size, and the method for storage. Results supported the reproducibility of multi-membrane sampling, and demonstrated that sampling efficiency can be improved using a larger membrane. However, ability to control the sampling environment and time was proved to be critical in order to obtain reliable information; the in vivo skin emission sampling was also influenced by skin metabolism and environmental conditions. Next, the method of storage was fully investigated for the membrane device before and after sampling. This investigation of storage permitted the sampling and instrument analysis to be conducted at different locations. Finally, the developed skin sampling device was applied in the identification of dietary biomarkers after garlic and alcohol ingestion. In this experiment, the previously reported potential biomarkers dimethyl sulphone, allyl methyl sulfide and allyl mercaptan were detected after garlic intake, and ethanol was detected after the ingestion of alcohol. Experiments were also conducted in the analysis of volatile organic compounds (VOCs) from upper back, forearm and back thigh of the body on the same individual. Results showed that 27 compounds can be detected from all of the 3 locations. However, these compounds were quantitatively different. In addition, sampling of the upper back, where the density of sebaceous glands is relatively high, detected more compounds than the other regions. In Chapter 4, a novel sample preparation method that combines the advantages of cold fiber and thin film was developed to achieve the high extraction efficiency necessary for high sensitivity gas sampling. A cooling sampling device was developed for the thin film microextraction. Method development for this sampling approach included evaluation of membrane temperature effect, membrane size effect, air flow rate and humidity effect. Results showed that high sensitivity for equilibrium sampling can be achieved by either cooling down the membrane and/or using a large volume extraction phase. On the other hand, for pre-equilibrium extraction, in which the extracted amount was mainly determined by membrane surface area and diffusion coefficient, high sensitivity was obtained by thin membranes with a large surface area and/or high sampling flow rate. In addition, humidity evaluations showed no significant effect on extraction efficiency due to the absorption property of the liquid extraction phase. Next, the limit of detection (LOD) and reproducibility of the developed cooling membrane gas sampling method were evaluated. LOD with a membrane radius of 1 cm at room temperature sampling were 9.24 ng/L, 0.12 ng/L, 0.10 ng/L for limonene, cinnamaldehyde and 2-pentadecanone, respectively. Intra- and inter-membrane sampling reproducibility had a relative standard deviation (RSD%) lower than 8% and 13%, respectively. Results uniformly demonstrated that the proposed cooling membrane device could serve as a powerful tool for gas in trace analysis. In Chapter 5, a particle-loading membrane was developed to combine advantages of high distribution coefficient and high surface area geometry, and applied in trace gas sampling. Bar coating, a simple and easy preparation method was applied in the preparation of the DVB/PDMS membrane. Membrane morphology, particle ratio, membrane size and extraction efficiency were fully evaluated for the prepared membrane. Results show that the DVB particles are uniformly distributed in the PDMS base. The addition of a DVB particle enhanced the stiffness of the membrane to some extent, and improved the extraction capacity of the membrane. Extraction capacity for benzene was enhanced by a factor of 100 when the membrane DVB particle ratio increased from 0% to 30%. Additionally, the prepared DVB/PDMS membrane provided higher extraction efficiency than pure PDMS membrane and DVB/PDMS fiber, especially for highly volatile and polar compounds. The high reproducibility of the prepared DVB/PDMS membrane in air sampling demonstrated the advantage of the bar coating preparation method, and also permitted quantitative analysis. Last, the prepared particle-loading membrane was applied to semi-quantitative and quantitative analysis of indoor and outdoor air, respectively. Both the equilibrium calibration method and diffusion-based calibration method were proposed for the quantitative analysis. Results showed that the high capacity particle-loading membrane can be used for monitoring trace analytes such as perfume components and air pollutants.

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.