Browsing by Author "Thurbide, Kevin"
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Item Open Access A developed metallomics method reveals the biochemical fate of Cd2+ and Hg species in erythrocyte lysate(2017) Gibson, Matthew; Gailer, Jürgen; Prenner, Elmar; Thurbide, Kevin; Osthoff, HansBioanalytical techniques that can be employed to obtain health-relevant information from biological fluids (i.e. erythrocytes) are urgently needed to gain new insight into the bioinorganic chemistry of non-essential metal species in the human body. To this end, a metallomics method was developed to probe the interaction of Cd2+, Hg2+, CH3Hg+ and thimerosal in the erythrocyte based on the direct analysis of erythrocyte lysate by size exclusion chromatography coupled on-line to an inductively coupled plasma atomic emission spectrometer (SEC-ICP-AES). This method development entailed systematic investigations into the sample preparation of the erythrocyte lysate (i.e. filtration to remove cell debris) as well into the identification of the ideal stationary phase and mobile phase. Filtering (0.45 μm pore-size Millex syringe-driven filers) and diluting (5-fold with corresponding buffer) resulted in the most consistent and reproducible results for the analysis of the erythrocyte lysate. A Superdex 75TM Increase 10/300 GL (300 x 10 mm I.D., 8.6 μm particle size) column that offers a fractionation range of 3 – 70 kDa was best suited for the separation of the major Cu, Fe and Zn metallospecies that are present in the erythrocyte lysate. 100 mM Tris(hydroxymethyl)-aminomethane (Tris) buffer (pH 7.4) was identified as the optimal mobile phase as it allowed for the separation of all the metallospecies of interest and gave the highest metal recovery of all the mobile phases (Zn: 95.8 ± 2.8% , Fe: 88.0 ± 7.2%). This developed metallomics method was subsequently employed to probe the comparative interaction of Cd2+, Hg2+, CH3Hg+ and thimerosal in erythrocyte lysate over a 6 h time period. The results that were obtained at time points ≥2 h revealed that ~85% of Cd2+ weakly interacted with hemoglobin (Hb), while ~13% eluted as (GS)xCd and ~2% bound to a ≥70 kDa Cd-binding protein. In contrast, ~6% of Hg2+ co-eluted with Hb at all time points, while ~94% eluted as (GS)xHg. The results for CH3Hg+ showed that ~5% of Hg co-eluted with Hb (constant over the 6 h time period), while for thimerosal (THI), this percentage gradually increased to 12% over the 6 h time period. The remaining Hg eluted as GS–HgCH3 and GS–HgCH2CH3, respectively. The co-elution of Hg with Hb – regardless of whether Hg2+, CH3Hg+ or THI was added – indicates that these interactions may adversely affect the function of Hb. The results demonstrate that the developed metallomics tool provided is ideally suited to obtain new insight into the bioinorganic chemistry and the toxicology of non-essential metal species within erythrocytes.Item Embargo A METHOD TO EXTERNALLY ADJUST THE COLUMN LENGTH IN GAS CHROMATOGRAPHY USING A WATER STATIONARY PHASE(Springer, 2023-12-06) Thurbide, Kevin; Shepherd, KadeItem Open Access Analysis of Sulfur Compounds Using a Water Stationary Phase in Gas Chromatography with Flame Photometric Detection(Analytical Methods, 2017-01-20) Thurbide, Kevin; McKelvie, KaylanThe properties of using a water stationary phase for analyzing organic sulfur compounds in capillary gas chromatography (GC) with a flame photometric detector (FPD) are presented. The water phase was not found to hinder FPD performance, which provided a detection limit near 30 pgS/s and excellent selectivity for sulfur over carbon. Several different organosulfur compounds were examined and found to be retained to varying degrees on the phase. In many cases, analyte water solubility and polarity appeared to correlate well with retention, whereas analyte volatility did not. By comparison, non-polar hydrocarbons were generally unretained in the system. This prevented their co-elution with sulfur analytes and the response quenching that is often observed in conventional GC-FPD. Of note, when a gasoline sample was analyzed on a standard DB-1 column, the response of the sulfur analytes present was found to be quenched by about 50% due to the overlapping hydrocarbon species also present. However, the same sample analyzed on the water stationary phase displayed no response quenching. Additionally, it was found that sulfur compounds present in different aqueous matrices such as wine, milk, and urine could also be readily and directly analyzed without interference, since many of the large hydrophilic matrix components present are often fully retained on the phase. Results indicate that this method can provide a useful alternative for the analysis of organosulfur compounds in complex matrices.Item Open Access Capillary Gas Chromatographic Separation of Carboxylic Acids Using an Acidic Water Stationary Phase(The final publication is available at Springer via http://dx.doi.org/10.1007/s10337-017-3333-z, 2017-08-01) Thurbide, Kevin; Darko, ErnestAn acidic water stationary phase is used for the analysis of carboxylic acids in capillary gas chromatography (GC). Under regular pH 7 operating conditions, these analytes are largely ionized and elute poorly, if at all, from the water phase. However, by adjusting the phase to pH 2, it is found that various acids are neutralized and can be readily eluted and separated in the system. Sulfamic acid is found to provide a stable pH for the water phase over time, whereas hydrochloric acid and other more volatile additives quickly evaporate from the column. Under optimal low pH conditions, the acidic analytes yield good peak shape and are readily observed for masses investigated down to 5 ng on-column. By comparison, on a conventional non-polar capillary GC column, the same analytes display threefold more peak tailing and are not detected for masses below 30 ng on-column. Through altering the phase pH, it is found that the selectivity between certain analytes can be potentially enhanced depending on their respective pKa values and/or ionizability. The analysis of various different samples containing carboxylic acids is demonstrated and the results indicate that this approach can possibly offer unique and beneficial selectivity in such determinations.Item Open Access Capillary Gas Chromatographic Separation of Organic Bases Using a pH-Adjusted Basic Water Stationary Phase(2016-08-26) Thurbide, Kevin; Darko, ErnestItem Open Access CHARACTERISTICS OF A NOVEL ALKALI FLAME IONIZATION DETECTOR AS AN AIR SENSOR FOR VOLATILE ORGANO-NITROGEN COMPOUNDS(Canadian Journal of Chemistry, 2024-06-22) Mogenson, Cole; Thurbide, KevinA novel alkali flame ionization detector (AFID) is introduced and characterized for use as an air sensor (i.e. without chromatographic separation) for organo-nitrogen compounds. Using a planar channeled quartz design, a simple, lightweight architecture for the portable device is presented, which yields sensitive and selective response toward nitrogen-containing analytes. For instance, the AFID sensor offers a detection limit of 30 pg N/s and a selectivity for nitrogen response over carbon of nearly 2 orders of magnitude. Further, nitrogen response is linear over the 1000-fold range of concentrations investigated. Relative to a flame photometric detector (FPD) device also used in a sensor mode, the AFID is observed to provide 100 times greater S/N values for nitrogen analytes with a nitrogen to carbon selectivity that is about 15 times larger. When using the AFID and FPD sensors in tandem, it is found that the response ratio of the simultaneous signals generated by each, produces characteristic values that more clearly identify the presence or absence of nitrogen in unknown analytes. The AFID sensor was used to detect organo-nitrogen analytes in several samples, and results indicate that it could be a useful approach for portable air sensing of nitrogen compounds.Item Open Access Characteristics of a Novel Alkali Flame Ionization Detector as an Air Sensor for Volatile Organonitrogen Compounds(2023-05-05) Mogenson, Cole Mitchell; Thurbide, Kevin; Kimura-Hara, Susana; Anikovskiy, Max; Thangadurai, VenkataramanThis thesis describes the introduction and characterization of a novel alkali flame ionization detector (AFID) for use as an air sensor for organonitrogen compounds without any chromatographic separation. Using a planar channelled quartz design, a simple, lightweight architecture for the portable device is presented, which yields a sensitive and selective response toward nitrogen-containing analytes over hydrocarbons. For instance, the AFID sensor offers a detection limit of 30 pg N/s and a selectivity for nitrogen response over carbon of nearly two orders of magnitude. Further, the nitrogen response was linear over the 1000-fold range of concentrations investigated. Relative to a flame photometric detector (FPD) device also used in a sensor mode under optimal conditions, the AFID was observed to provide over a 160 times greater S/N value for nitrogen analytes with a selectivity of nitrogen over carbon that was about 16.6 times larger. When using the AFID and FPD sensors in tandem, it was found that the response ratio of the simultaneous signals generated by each produced characteristic signal ratio values that more clearly identified the presence or absence of nitrogen in unknown analytes. The AFID sensor was also used to detect organonitrogen analytes in several sample matrices. Results indicate that signal response was largely unaffected by these potentially interfering sample conditions, and thus this method could be a valuable approach for portable air sensing of nitrogen compounds.Item Open Access Characterization and Applications of a Water Stationary Phase in Capillary Gas Chromatography(2014-09-12) Gallant, Jonathan; Thurbide, KevinNew stationary phases in gas chromatography (GC) are constantly being investigated. In particular, new polar stationary phases are of interest due the limited number of different ones available versus the abundance of different non-polar phases available. Water is a very polar compound which also possesses other benefits such as its environmentally compatibility, abundance and low retail cost. Water has previously been investigated as a stationary phase in packed column GC. This resulted in an inefficient stationary phase that largely evaporated during operation. This thesis details an investigation of how to form and maintain a water stationary phase in a capillary column GC setting without any significant evaporation. This novel capillary stationary phase yielded separations with almost two full orders of magnitude greater efficiency than the packed column GC water phase. Furthermore, it also possessed an analyte selectivity trend which is totally unique in capillary column GC and the interesting ability to significantly alter/reverse analytes selectivity with oven temperature. The major operating parameters are presented and discussed, and the system is applied to the analysis of several samples to better characterize its performance.Item Open Access Characterization of Novel Materials as Platforms for Performing Microfluidic Gas Chromatography(2013-04-23) Darko, Ernest; Thurbide, KevinAnalytical Gas Chromatography (GC) separation techniques are constantly being developed to reduce analysis time and cost as well as improve sensitivity and accuracy. One such development is the fabrication of miniaturized microfluidic columns for use in GC. There are vast reports of miniaturized columns fabricated in silicon and even other polymeric materials. While these devices show good separation efficiency, they lack physical robustness and the thermal stability demanded by GC. Alternatively, Low Temperature Co-fired Ceramics (LTCC) and titanium are novel materials that show promise for use in microfluidic GC column fabrication. They offer advantages such as low cost, ease of fabrication, and additionally, these materials are quite strong and can withstand the high temperatures required in GC. LTCC together with titanium metals have been studied and characterized as alternative platforms for microfluidic GC in this thesis. Both LTCC and titanium tiles produced good results that compared well with commercially available GC columns. For example, a 7.5m long channel within an 11 cm x 5.5 cm LTCC tile under optimum conditions generated theoretical plates for a dodecane test analyte of about 14327 compared to 4507 for a 7.5 m long commercial capillary column. Similarly, a 15m long channel within a 15 cm x 8 cm titanium tile produced 10377 plates for the same test analyte. Both of these tiles showed high resolving power, yielding benzene – toluene resolutions of about 14.07 and 8.29 respectively for LTCC and titanium. Peak capacity was also probed using temperature programming with a simple nC8 – nC20 alkane mixture. A cumulative peak capacity of about 53 was obtained for the LTCC tile while the titanium tile gave a value of 48. Polar analyte separations on both often produced peaks with a greater degree of tailing. Additionally, packed columns fabricated on these materials were also investigated, and produced good separation efficiency with negligible flow restriction. For example, a 10 cm long channel within a 5.5 cm x 2.5 cm LTCC tile packed with 5µm C18 particles generated 2710 plates per meter. Likewise, a 10 cm long channel within a 9 cm x 5 cm titanium tile packed with 1.7µm C18 particles also produced 8430 plates per meter; a three fold increase. Neither displayed any adverse effects from operating the tiles up to 60 atm of carrier gas pressure. Results indicate that LTCC and titanium make excellent platforms for microfluidic GC. Further exploration of their properties in this area will be useful.Item Open Access Characterization of Planar Titanium Platforms for Flame Ionization Detection in Microfluidic Gas Chromatography(2016) Raut, Rahul Pandurang; Thurbide, Kevin; Hinman, Allen Scott; Gailer, Jürgen; Marriott, RobertGas chromatography (GC) with a Flame Ionization Detector (FID) has been widely used for the analysis of volatile organic compounds in various fields. Instrument portability and miniaturization of the FID for micro GC (μGC) applications are of increasing interest. This thesis describes the design and characterization of a planar on-chip counter current micro FID (μ-FID). The μ-FID fabricated in both quartz and Titanium (Ti) substrates were characterized and the Ti μ-FID showed great improvements in detection limit and sensitivity over other prototypes. This Ti μ-FID design is further integrated with a Ti separation column to fabricate a planar μGC-FID Ti tile for the first time. This Ti μGC-FID tile is explored for its detector performance attributes and some routine GC applications are examined. This novel Ti μGC-FID tile, with an on-chip single monolithic design, is found to provide a very low detection limit (9 pgC/s) and a high sensitivity (60 mC/gC).Item Open Access Characterization of Titanium Tiles as Novel Platforms for Micro Flame Ionization Detection in Miniature Gas Chromatography(Springer, 2017-05-05) Thurbide, Kevin; Raut, RahulItem Open Access Development of Purge-and-Trap Sample Preconcentrator for Enhanced Detection of Alkyl Nitrates by Thermal Dissociation Cavity Ring-Down Spectroscopy(2016) Ye, Connie; Osthoff, Hans; Thurbide, Kevin; Gailer, Jürgen; Marriott, RobertThis thesis describes the development of a sample preconcentrator for enhanced detection of alkyl nitrates (∑ANs) in ambient air by thermal dissociation cavity ring-down spectroscopy (TD-CRDS). The recovery of isopropyl nitrate on Tenax adsorbent was (96±1)% and unaffected by potential interfering gases such as ozone and nitrogen dioxide. Mixtures of five alkyl nitrates were also recovered in high yield in dry (99±5)% and in humidified air (92±11)% with relative humidity of 83%. Results from the first field deployment of the new instrument from the Ozone-depleting Reactions in a Coastal Atmosphere (ORCA) campaign are presented. The ORCA campaign took place at the Amphitrite Point Observatory on the West coast of Vancouver Island in Ucluelet, B,C. from July 6-31, 2015. A signal to noise ratio of 16.8 and a limit of detection of 7 pptv were demonstrated in the field. Future applications include measurements of isoprene and monoterpene nitrates.Item Open Access Development of Sustainable Nanosorbcats Based Technology for Hydrocarbons and Organic Pollutants Recovery from Industrial Wastewater(2017) El-Qanni, Amjad; Nassar, Nashaat N.; De Visscher, Alex; Hassanzadeh, Hassan; Thurbide, Kevin; Hussien, Muataz A.The worldwide shortage of fresh water and the huge competing demands from a variety of users stimulate an urgent need for finding innovative wastewater treatment processes. For instance, oil sand process-affected waters pose a critical energy issue and an environmental alert since these effluents are toxic to many aquatic and non-aquatic living organisms. In addition, some of these pollutants are non-biodegradable and, thus they will exist for a long time in the environment, which may cause a real challenge to the conventional wastewater treatment processes. Accordingly, economically viable and environmentally sound techniques are needed. The application of nanoparticle technology as adsorbents and catalysts (nanosorbcats), whether as a standalone or as an enabling technology, in cleaning up wastewater has recently received great attention. This is because of the unique chemical and physical properties of nanoparticles in comparison with their counterparts, which make them superior to the conventional adsorbent/catalysts. Hence, in the present study, the employment of newly in-house prepared silica-embedded nanosorbcats functionalized with active species of NiO and MgO for cleaning up produced water was investigated. A facile co-precipitation synthesis route was used to prepare those nanosorbcats, which were characterized by different characterization techniques like XRD, BET, HRTEM, CO2-TPD, and IR spectroscopy. The prepared nanosorbcats were then employed for the adsorptive removal of cationic, anionic, and organic acid model molecules. Computational modeling, DFT calculations, and MD simulations of the interaction between the model molecules and the surfaces of prepared nanoparticles were carried out to get more mechanistic insights into their adsorptive behaviors. Eventually, these nanosorbcats were successfully used to treat real SAGD produced waters within an experimental scheme including three processes, namely; oxy-cracking, packed-bed adsorption, and catalytic steam gasification.Item Open Access Expanding the capabilities of an acoustic flame detector for chromatography(2009) Mah, Christine; Thurbide, KevinItem Embargo Flameless operating mode for improved multiple flame photometric detection in gas chromatography(Springer Nature, 2024-04-25) Thurbide, Kevin; Nguyen, BaoA novel fameless operating mode is introduced, which improves the response of a multiple fame photometric detector (mFPD). The mFPD normally has analyte travel through 4 ‘worker’ fames in series before entering a fnal ‘analytical’ fame where its emission is monitored. Here, it is found that when the analytical fame is not ignited, background luminescence is reduced over 30 times and the strong analyte chemiluminescence of the worker fames can be made to extend a large distance (~10 fame widths) into the analytical fame region where it is detected. This occurs for phosphorous (HPO*), quadratic sulfur (S2*), and linear sulfur (HSO*) emission. Conversely, carbon emission resides inside the worker fames and yields a small negative signal. As a result, very good selectivity over carbon is observed, and improved minimum detectable limits (MDL) of 4 pg S/s (S2*) and 0.3 pg P/s (HPO*) are obtained, which are up to 20 times lower than previous values reported for the mFPD. Further, linear sulfur (HSO*) yields an MDL of 6 pg S/s, which is over 3 times lower than values reported for other FPDs. Due to the worker fames present in this mode, other benefts of regular mFPD operation are maintained, like uniform analyte response and large quenching resistance. In application, a trace benzothiophene analyte is readily detected within a concentrated diesel fuel matrix in the fameless mFPD mode, while no response is observed in the conventional FPD mode. Results indicate that this fameless operating mode is advantageous for sulfur and phosphorous analysis.Item Open Access Investigating Novel Methods for Using Water in Analytical Extractions and Separations(2015-12-10) Murakami, Jillian Nicole; Thurbide, Kevin; Hinman, Allen Scott; Osthoff, Hans; Shi, Yujun; Raynie, DouglasThis thesis describes the development of novel methods for using water in analytical extractions and separations to reduce organic solvent use, decrease environmental impact and lower operation costs. The first area of exploration is the sample preparation of pharmaceutical formulations, which is conventionally time consuming and organic solvent intensive. Here, subcritical water extraction (SWE) is employed as an inexpensive and environmentally friendly technique to rapidly extract active pharmaceutical ingredients from commercial formulations using only water as the solvent. Quantitative recoveries are obtained from different sample forms including capsule contents and intact tablets, the latter of which demonstrates the potential of SWE to minimize sample handling. Overall, SWE is shown to be a potentially viable method for fast, inexpensive and green sample preparation of pharmaceuticals in both capsule and tablet form. Next, the coating properties of a water stationary phase in a capillary supercritical fluid chromatography (SFC) system are investigated. It is shown that the water phase is uniformly deposited inside stainless steel (SS) columns of varying length and i.d., resulting in a consistent water coverage per area. Hydrofluoric acid etching is explored to increase water stationary phase volume, where prolonged etching of the inner capillary wall served to double water volume and analyte retention. Results indicate that etching could be a useful method to control the volume of water in the column while still maintaining good chromatographic peak shapes and plate heights. Finally, the utility of a water stationary phase is expanded by demonstrating the use of SS particles as a novel support for this phase in a packed column SFC format. Compared to analogous separations employing a water stationary phase coated onto a SS capillary column, the packed column gives faster separations and larger analyte retention factors with comparable plate heights and good peak shapes. Further, the increased volume of stationary phase in the packed column leads to a larger sample capacity. Several applications of the packed column system are examined, and the results indicate that it is a useful alternative to the capillary column mode, particularly where analyte loads or sample matrix interference is a concern.Item Open Access Mapping the Unexplored Reactivity Landscape of Benzo[ghi]perylene(2024-04-16) Hogan, David Thomas; Sutherland, Todd Christopher; Derksen, Darren; Heyne, Belinda; Thurbide, Kevin; Zhao, YumingThis thesis describes the learning opportunities, failures, and successes surrounding a polycyclic aromatic hydrocarbon of interest, benzo[ghi]perylene. Neglected in the chemical synthesis literature but fundamentally interesting due to its composition and molecular symmetry, the work contained herein contributes a small work to a small field. The efforts are found in three chapters for three chronologically and ideologically related topics: the construction and optimization of a flow photoreactor to produce benzo[ghi]perylene; the exploration of structure and reactivity of benzo[ghi]perylene; the development of a strategy to improve the flow photochemical productivity of benzo[ghi]perylene.Item Open Access Novel flame photometric detection methods using counter-current flames and packed-column supercritical fluid chromatography(2004) Cooke, Bradley Wallace; Thurbide, KevinA novel analytical device, the counter-current flame photometric detector (ccFPD), has been developed for gas chromatography, based upon emission from a counter-current air flame, which burns in an opposing stream of hydrogen and column effluent. This device demonstrated excellent stability over a wide range of gas flows. Sensitivity toward phosphorus and sulfur was determined and a linear sulfur emitter was exploited by premixing air with hydrogen/effluent flow. This device conventional FPD was developed and the background emission characteristics of supercritical CO2 and supercritical argon were evaluated and compared. While supercritical CO2 displayed intense emission, supercritical argon was transparent, yielding the same spectrum as an FPD flame without effluent. This translated to a 10 fold increase in sensitivity for sulfur when supercritical argon is used rather than supercritical CO2.Item Open Access Novel instrumental methods for supercritical fluid chromatography(2007) Li, Jian Jun; Thurbide, KevinThis thesis explores five main research themes all aimed at improving the capabilities of supercritical fluid chromatography (SFC) using both packed (pSFC) or capillary (cSFC) columns. In the first study, the addition of a high water content into a 2-propanol modifier was explored in pSFC. With this new modifier, very polar compounds (e.g. ionic salts, polyhydroxycarboxylic acids, and amino acids) can be readily eluted from non-polar and polar columns. In a second study, both an ultrasonic bath and probe were each employed in SFC separations but did not demonstrate any great effect. Next, in studying the restoration of column efficiency loss caused by pressure drops, a small resistively heated coil at the colunm inlet was found to improve the peak shape significantly. In the last two studies, this heating coil was further used to control column pressure and flow rate independently in both cSFC and pSFC.Item Open Access Novel micro counter-current flame based detection methods for gas chromatography(2010) Hayward, Taylor Curtis; Thurbide, Kevin