This thesis presents enhanced analytical methods developed for complex aqueous sample analysis based on solid phase microextraction (SPME). First, the laboratory evaluation of the kinetic calibration approach in aqueous sample analysis using SPME is discussed. A modified SPME device, Polydimethylsiloxane (PDMS) rod passive sampler, was developed and the kinetic calibration method based on the standard preloaded in the extraction phase was applied to determine the time-weighted average (TWA) concentration of organic pollutants in water. Later, the SPME technique was used to investigate the complex interactions between the organic pollutants and humic organic matter (HOM) present in the aqueous samples. The kinetics of the SPME approach in complex aqueous samples was studied. The concentration of freely dissolved analytes and the total concentration of the target analytes in the sample matrix were determined by SPME sampling. The usefulness of the SPME approach for binding studies was further demonstrated by determining the sorption coefficient, a useful parameter for studying the bioavailability of the organic pollutants in the environment. In addition, the commercial Computational Fluid Dynamics (CFD) software COMSOL Multiphysics was used to predict the kinetics of analyte extraction and flow pattern under different experimental conditions using the SPME technique. A good agreement between the prediction and the experimental data confirms the advantages of the CFD application for experimental optimization thus minimizing the need of extensive experiments.

Solid phase microextraction (SPME) has gained much popularity for in vivo applications recently. Thus far, there are two types of pre-equilibrium kinetic calibration that have been applied to in vivo SPME: on-fibre standardization and dominant pre-equilibrium desorption. Both of these techniques have their own advantages and disadvantages. To address the limitations presented by these two techniques, a third pre-equilibrium kinetic calibration method, the diffusion-based interface model, was investigated. The diffusion-based interface model had been successfully applied to air and water samples but was never utilized for in vivo SPME studies. For the first part of the research, on-fibre standardization, dominant pre-equilibrium desorption, and diffusion-based interface model were compared in terms of accuracy, precision, and experimental procedures, by using a flow-through system. These three kinetic calibrations were further validated by equilibrium SPME extraction and protein-plasma precipitation, a current state-of-the-art sampling method. The potential of diffusion-based interface model was yet again demonstrated in the second part of the research project. This calibration method was applied to comparative pharmacokinetic studies of two drugs, fenoterol and methoxyfenoterol, on 5 rats. To provide a constant sampling rate as required for diffusion-based interface model, a SPME animal sampling autosampler, AccuSampler®, was utilized. It custom-written program allowed the entire SPME sampling procedure excluding insertion and removal of SPME probes to be automated. Furthermore, to validate the results obtained by SPME, the AccuSampler® was programmed to withdraw blood after each SPME sampling time point for conventional method analysis using protein-plasma precipitation. The well correlated data obtained by SPME sampling and the conventional method illustrated the potential of diffusion-based interface model as an excellent choice for future in vivo SPME applications.

The traditional approach for predicting the risk of hydrophobic organic contaminants in sediment is to relate organic carbon normalized sediment concentrations to body residues or toxic effects in organisms. This method is limited, however due to the plethora of variables that can influence bioavailability. Therefore, a matrix independent method of predicting bioavailability needs to be developed in order to be universally applicable. Solid phase microextraction (SPME) and Tenax are two commonly used bioavailability-based methods. While both SPME fiber and Tenax extractable concentrations can be correlated to tissue residues of aquatic species, the majority of this research (with a few exceptions) focuses on compounds that are not acutely toxic or biotransformed. Less is known about the potential applicability of these methods to predict bioaccumulation, and ultimately toxicity, for highly toxic, rapidly biotransformed compounds, such as pyrethroid insecticides. This class of compounds is of particular concern due to frequent environmental detection in sediments at concentrations lethal to benthic species. This research has four specific goals: Determining exposure conditions that may change the concentration on the SPME fibers at equilibrium (Chapter 2); Comparing the ability of SPME fibers and Tenax to predict the bioavailability of two pyrethroids (permethrin and bifenthrin) (Chapter 3); Developing bioavailability-based toxicity endpoints for bifenthrin using two aquatic species (Chapter 4); and, Validating these techniques using sediments from known contaminated field sites (Chapter 5). Overall this research was focused on comparing and contrasting the ability and applicability of SPME fibers and Tenax to adequately predict the exposure of pyrethroids under varying conditions. While comparing these two methods, they were optimized to better provide accurate predictions of bioavailability and toxicity for pyrethroids from sediments. Regardless of the fiber or animal density examined, the SPME fibers exposure did not significantly affect fiber concentrations for permethrin or DDE. Additionally, bioaccumulation of parent permethrin and bifenthrin was predicted using both SPME fibers and Tenax using 6 or 24 h extraction times. Further, a single regression model predicted bioaccumulation across compounds and species using Tenax extractable concentrations. Once demonstrated that these techniques could predict bioaccumulation, median lethal and effect levels were examined for bifenthrin and as expected the bioavailability-based endpoints were more uniform across sediments than use of whole sediment concentrations. Additionally, the relationships among the two methods were compared across multiple sediments. Despite the SPME fiber's ability to determine toxicity in laboratory sediments, the field validation study determined that lethal levels were often too low to detect on the SPME fibers using current methodologies, but Tenax extractable concentrations correlated to toxicity. Overall, while both methods could predict bioavailability, the limitations of SPME fibers including lower sensitivity, inability to function across compounds, and long equilibration time, made Tenax extraction a preferable method.

This thesis project describes research using headspace solid phase micro-extraction with gas chromatography (HS-SPME GC-MS) as an analytical tool for assessing textile fibres. It was found that this method required a temperature of >500oC to pyrolize the textile sample. A total of 5 minutes was determined to be the optimal time for collecting the volatile analytes. Numerous analytes were found to be chemical markers for each of the individual textile fibres. The chemical markers are qualitatively used to describe each textile uniquely, and it was found that by using the chromatographic patterns, the textiles could be identified individually and in mixtures containing two textiles. Lastly, by accelerating the age of the textile fibres by means of heat, ultra-violet light, and humidity, a comparison was made between the un-aged and aged fibres. It was found that each of the techniques arose different results and in some cases new compounds. / October 2016

No description available.

Until recently, multiple SPME fibres could not be automatically evaluated in a single sequence without manual intervention. This drawback had been a critical issue until recently, particularly during the analysis of numerous on-site samples. Recently, GERSTEL® has developed and commercialized a Multi-Fibre Exchanger (MFX) system designed to overcome this drawback. In this research, a critical evaluation of the MFX performance in terms of storage stability and long term operation is presented. It was established in the course of our research that the MFX can operate continuously and precisely for over 200 extraction/injection cycles. However, when the effect of residence time of commercial fibres on the MFX tray was evaluated, the results have shown that amongst the evaluated fibre coatings, carboxen/polydimethylsiloxane (CAR/PDMS) was the only coating capable of efficient storage on the MFX tray for up to 24 hours after field sampling without suffering significant loss of analytes. Additionally, the MFX system capability for high-throughput analysis was demonstrated by the unattended desorption of multiple fibres after on-site sampling of two different systems, indoor air and biogenic emissions. Subsequently, a protocol based on a new, fast, reproducible, reusable and completely automated method that enables quick assessment of SPME coatings was developed. The protocol consists of an innovative in-vial standard generator containing vacuum pump oil doped with McReynolds probes and subsequently mixed with a polystyrene-divinylbenzene resin. According to our results, the protocol has proven to be a useful tool for the quick assessment of inter-fibre reproducibility prior to their application in on-site analysis. The implications of such protocols include, but are not limited to: time-saving, assurance of reliable and reproducible data, and a dependable guide for novice users of the technique. Finally, an innovative, reusable and readily deployable pen-like diffusive sampler for needle traps (PDS-NT) is proposed. Results have shown that the new PDS-NT is effective for air analysis of benzene, toluene, and o-xylene (BTX). In addition, no statistically significant effects of pen geometry on the uptake of analytes were found.

No description available.

The cold fiber solid phase microextraction (SPME) system was improved by minimizing the coating temperature fluctuation range, and the performance of the system was evaluated by investigating the extraction of PAHs from spiked sand samples. The coating temperature can be made relatively constant and the relative standard division (RSD) for most compounds was smaller than 2%. A simplified cold fiber system without the solenoid valve was modified to connect CO2 delivery tubing directly to the liquid CO2 tank. The robustness of this system was evaluated with different sizes of CO2 delivery tubings. The system is stable, low cost and can be easily controlled, which provides a supplementary extraction strategy to the traditional cold fiber system. The extraction amount of the analyte in a specific system was calculated theoretically in advance. The extraction amount for the experiment agreed with that of the calculated result. By using theoretical calculations as a guide, desorption efficiency for aged spiked samples was investigated. In order to achieve better extraction efficiency for PAHs, a programmed coating temperature method was developed and optimized, which led to higher extraction efficiency for most studied analytes compared to the traditional methods. In real sample analysis, certified reference soils were analyzed using cold fiber SPME and the addition of diethylamine successfully realized the exhaustive extraction for volatile compounds and enhanced the recoveries for semi-volatile compounds. Satisfactory extraction amounts for all compounds were achieved by the proposed method after method optimization.

Accurate characterization of risk of adverse ecological effects related to contaminated sediment presents a particularly difficult challenge. A series of studies has been conducted to investigate the utility of various tools for assessment of sediment toxicity. The goal of this research was to provide information which could help increase the accuracy with which predictions of toxicity could be made at hazardous sites. A calibration study was conducted using model PAHs, PCBs, a binary PAH mixture and a coal-tar mixture. This study was a collaborative effort among five university-based Superfund Research Programs (SRPs). Each program, with the help of funding through the NIEHS Superfund Research Program, has developed a chemical-class specific assay to estimate toxicity of contaminants in sediment. This suite of bioassays expands the range of data typically obtained through the use of standard aquatic toxicity assays. A series of caged in situ exposure studies has been conducted using juvenile Chinook salmon and Pacific staghorn sculpin in the Lower Duwamish Waterway. The study aimed to investigate the utility of selected biomarkers in evaluating the relationship between contaminants present in environmental samples and response in receptors following an in situ caged exposure. Results found that DNA adducts detected in exposed fish were significantly higher than controls in 2004 and 2006, and DNA adducts appear to be a reliable indicator of exposure, although no dose-response relationship was present. Western blot analysis of CYP1A1 was not indicative of exposure levels. The final study conducted was concerned with evaluating the utility of using solid phase microextraction (SPME) fibers in situ to evaluate contaminated sediment. Levels of PAHs and PCBs in sediment often exceeded sediment quality guidelines; however, results from aquatic toxicity bioassays using Hyalella azteca were mostly negative, thus levels of contaminants detected on SPME fibers could not be associated with adverse effects in Hyalella. However, regression analysis of total PAHs present in sediment and levels of PAHs detected in porewater SPME fiber samplers, which were placed 5 cm into the sediment for 30 days, revealed a strongly correlated linear relationship (R2 = .779). Normalization of the sediment data to total organic carbon was performed to determine if the trend would remain present, and the linear relationship was again confirmed (R2 =.709).

Until recently, multiple SPME fibres could not be automatically evaluated in a single sequence without manual intervention. This drawback had been a critical issue until recently, particularly during the analysis of numerous on-site samples. Recently, GERSTEL® has developed and commercialized a Multi-Fibre Exchanger (MFX) system designed to overcome this drawback. In this research, a critical evaluation of the MFX performance in terms of storage stability and long term operation is presented. It was established in the course of our research that the MFX can operate continuously and precisely for over 200 extraction/injection cycles. However, when the effect of residence time of commercial fibres on the MFX tray was evaluated, the results have shown that amongst the evaluated fibre coatings, carboxen/polydimethylsiloxane (CAR/PDMS) was the only coating capable of efficient storage on the MFX tray for up to 24 hours after field sampling without suffering significant loss of analytes. Additionally, the MFX system capability for high-throughput analysis was demonstrated by the unattended desorption of multiple fibres after on-site sampling of two different systems, indoor air and biogenic emissions. Subsequently, a protocol based on a new, fast, reproducible, reusable and completely automated method that enables quick assessment of SPME coatings was developed. The protocol consists of an innovative in-vial standard generator containing vacuum pump oil doped with McReynolds probes and subsequently mixed with a polystyrene-divinylbenzene resin. According to our results, the protocol has proven to be a useful tool for the quick assessment of inter-fibre reproducibility prior to their application in on-site analysis. The implications of such protocols include, but are not limited to: time-saving, assurance of reliable and reproducible data, and a dependable guide for novice users of the technique. Finally, an innovative, reusable and readily deployable pen-like diffusive sampler for needle traps (PDS-NT) is proposed. Results have shown that the new PDS-NT is effective for air analysis of benzene, toluene, and o-xylene (BTX). In addition, no statistically significant effects of pen geometry on the uptake of analytes were found.