GCxGC-TOFMS

Body odour consists of different compounds that interact in various ways with textile materials due to differences in their chemical properties. Clothing made from hydrophilic fibres (e.g., cotton) can be more easily laundered, and odorants more effectively removed than those made from hydrophobic fibres (e.g., polyester). Therefore, the purpose of this research was to examine the interactions between textile materials and odorous compounds when washed several times with different detergents. Test fabrics were of both interlock knit structure and either 100% cotton (234 g/m 2 ) or 100% polyester (224 g/m 2 ) fibre content. Test compounds were 4-ethyl octanoic acid (octanoic acid) and 2-nonenal (nonenal). Fabric samples were spiked with 10 µL of a solution of octanoic acid (0.1g), nonenal (0.1g) and dichloromethane (solvent) and left to sit for 24 hours. Inoculated samples were washed with either Tide® Free and Gentle detergent or Tide® Febreze Sports detergent. Residual odorants were measured using gas chromatography with flame ionization detector. Headspace analysis of volatiles was conducted using solid-phase micro-extraction (SPME); direct extraction of compounds remaining in fabrics was done using dichloromethane as the solvent. Considering the peak area of odorants, findings show that cotton generally retained and desorbed lesser odorous compounds than polyester did. Interestingly, the non-polar nonenal was difficult to remove from the non-polar hydrophobic polyester by washing, which resulted in higher quantities of nonenal compared with octanoic acid in the headspace. Also, while multiple washes eventually became more efficient in removing odorants from cotton, polyester did not clean as well. iii Preface This thesis is an original work by Mohammed Mukhtar Abdul-Bari. No part of this thesis has been previously published.

This study presents and discusses the state of the art of Two-Dimensional Comprehensive Gas Chromatography (GC×GC) developed in Brazil. GC×GC has been the focus of studies in Brazil since 2009, based on successful experiences in cooperation with researchers from Australia and Italy. The result of these researches led to the installation of many laboratories in Brazilian Universities and Research Centers, similar to others in foreign countries and the development of research, mostly involving applications of the technique to Brazilian matrices. In this review we present applications of GC×GC involving the pyrolysis of Brazilian agroindustrial residues, such as cane straw, sawdust, coconut fiber, fruit seeds, rice husks, spent coffee grounds, among others. The most used detection techniques for GC×GC have been mass spectrometry with fast quadrupole analyzer (GC×GC/qMS) and time of flight (GC×GC/TOFMS). These studies showed the possibility of identifying many organic compounds in the bio-oils produced, especially oxygenated ones such as phenols, ketones, acids and esters. Several studies suggest catalytic pyrolysis as a way to generate less oxygen-compounds directing the application of this bio-oil to the area of biofuels. However, the compounds found and their relative concentration, indicates that the best uses should be associated with the processing industry such as pharmaceuticals, chemicals, polymers and food.

This study presents and discusses the state of the art of Two-Dimensional Comprehensive Gas Chromatography (GC×GC) developed in Brazil. GC×GC has been the focus of studies in Brazil since 2009, based on successful experiences in cooperation with researchers from Australia and Italy. The result of these researches led to the installation of many laboratories in Brazilian Universities and Research Centers, similar to others in foreign countries and the development of research, mostly involving applications of the technique to Brazilian matrices. In this review we present applications of GC×GC involving the pyrolysis of Brazilian agroindustrial residues, such as cane straw, sawdust, coconut fiber, fruit seeds, rice husks, spent coffee grounds, among others. The most used detection techniques for GC×GC have been mass spectrometry with fast quadrupole analyzer (GC×GC/qMS) and time of flight (GC×GC/TOFMS). These studies showed the possibility of identifying many organic compounds in the b...

Conclusions The treatment failure group was characterized by an imbalanced gut microbiome, in addition to elevated levels of metabolites associated with abnormalities in the long-chain fatty acid β-oxidation pathway, accompanied by reduced l-carnitine and short-chain fatty acids, indicative of a mitochondrial trifunctional protein defect in particular. Furthermore, an altered amino acid metabolism was also observed in these patients, which confirms previous findings and associations to increased interferon gamma due to the host's immune response to M. tuberculosis and a compromised insulin secretion.

The ever-increasing requirement for determination of environmental pollutants and studies of comprehensive metabolite networks in complex real-life samples parallel advancements in solid-phase microextraction (SPME). The availability of stateof-the-art analytical instrumentation offering higher sensitivity and specificity has contributed to an increased range of applications covered by SPME. This review summarizes the most basic aspects in SPME development, addresses some of the challenges encountered in the analysis of food and environmental samples, and particularly emphasizes complex sample analysis. We also outline the development of new extracting materials, novel sampling configurations and approaches compatible with complex sample and/or on-site determinations. To serve as a guide to potential opportunities for continued innovation in SPME applications, we especially emphasize the evolution of on-site and in vivo SPME techniques and their feasibility for targeted determination of organic pollutants and biologically-active compounds, and global metabolite analysis.

Urinary metabolomics offers a non-invasive means of obtaining information about the system-wide biological health of a patient. Untargeted metabolomics approaches using one-dimensional gas chromatography (GC) are limited due to the chemical complexity of urine, which poorly detects co-eluting low-abundance analytes. Metabolite detection and identification can be improved by applying comprehensive two-dimensional GC, allowing for the discovery of additional viable biomarkers of disease. In this work, we applied comprehensive two-dimensional GC coupled with time-of-flight mass spectrometry (GC×GC-TOFMS) to the analysis of urine samples collected daily across 28-days from 10 healthy female subjects for a personalized approach to female reproductive health monitoring. Through this analysis, we identified 935 unique volatile metabolites. Two statistical methods, a modified T-statistic and Wilcoxon Rank Sum, were applied to analyze differences in metabolome abundance on ovulation days as compared to non-ovulation days. Four metabolites (2-pentanone, 3-penten-2-one, carbon disulfide, acetone) were identified as statistically significant by the modified Tstatistic but not the Rank Sum, after a false-discovery rate of 0.1 was set using a Benjamini-Hochberg correction. Subsequent analyses by boxplot indicated that the putative volatile metabolic biomarkers for fertility are expressed in increased or decreased abundance in urine on the day of ovulation. Individual analysis of metabolome expression across 28-days revealed some subject-specific features, which suggest a potential for long-term, personalized fertility monitoring using metabolomics.

Conventional comprehensive two-dimensional gas chromatography (2D-GC or GC Â GC) is now widely used for middle distillates analysis; only a few applications are devoted to heavy fractions such as vacuum gas oils or vacuum residues. A recent extension of GC Â GC range in suitable high temperature conditions allowed quantitative analysis of a full vacuum gas oil (VGO) up to nC 60. Considering this study as a new breakthrough for the challenge of heavy petroleum fractions analysis, the application of high-temperature two-dimensional gas chromatography (HT-2D-GC) to 12 VGOs from different origins (geographic and processes) and one de-asphalted oil (DAO) is described in this paper. The comparison with standardized methods, liquid chromatography and mass spectrometry, illustrates the reliability of the method for heavy cuts analysis. Furthermore, quantitative distributions by chemical families could be built for the first time, which allow a better description and more relevant comparisons between heavy petroleum fractions. Except for heavier cuts such as DAO, this powerful technique is widely applicable on VGO fractions. These results should increase the analytical information concerning heavy cuts and will be helpful to understand reactions involved in petroleum processes.

Concerns over the toxicity associated with 'naphthenic' acids (NA) within oil produced waters and oil sands process waters (OSPW), whether justified or not, have increased the need for the structural elucidation of NA. Certainly, oil sands mining operations, such as those in Alberta, Canada, result in the production of large volumes of OSPW contaminated with NA. Monitoring NA, predicting the toxicities and accounting for the toxicity of residual NA after clean-up treatments, have all been hindered by the lack of NA identifications. Recently, a method involving the conversion of the esters of petroleum NA to the corresponding hydrocarbons before analysis by comprehensive two-dimensional gas chromatography-mass spectrometry (GC×GC-MS), resulted in the most comprehensive study of bicyclic NA from petroleum to date. Here, we present results of the analysis by GC×GC-MS of NA extracted from OSPW after conversion of the acids or ester derivatives to the corresponding hydrocarbons. The identifications presented include novel alicyclic, aromatic and sulphur-containing hydrocarbons and thus, by inference, of the corresponding acids. This supports and significantly extends, previous identifications of OSPW NA as their methyl esters and can now be used to better inform environmental monitoring programs and toxicity studies.

Identification of individual petroleum acids ('naphthenic' acids, NA) has proved challenging for decades, due to the extreme complexity of many petroleum acid mixtures. This has hindered detailed understanding of the role of NA in petroleum generation and oil production processes, refinery corrosion, as wood preservatives, and as environmental toxicants. Some recent advances have been made due to improved chromatographic separation of esters of the acids by multi-dimensional gas chromatography-mass spectrometry (GC×GC-MS), but relatively few reference spectra of esters are available for comparison. Here we report a complementary method based on a combination of a modified historical approach of converting NA to the corresponding hydrocarbons, followed by analysis by GC×GC-MS. Many published spectra exist for reference hydrocarbons making comparisons of reference spectra with those of the unknowns, much more feasible. As an example, we report identification of over 30 individual bicyclic naphthenic acids as the bicyclane hydrocarbons. These include both fused and bridged acids possessing methyl, dimethyl and ethyl alkyl substituents, as well as some terpenoid-derived acids. The study provides the most comprehensive analysis of one of the major classes of NA (the bicyclic acids) to date. There is now clear potential for this method to be used for the structural elucidation of other unknown acids (e.g. oil sands acids) and functionalised biomarkers in complex mixtures.

overcome disposal issues. Raffinate column bottom (RCB) is generated as a by-product in linear alkyl benzene (LAB) plants. The hydrotreater unit of a LAB plant significantly removes sulfur, nitrogen, and olefins from kerosene followed by extraction of normal paraffin which is used for the alkylation of benzene to produce LAB. The remaining raffinate (180-230 °C) mainly comprises isoparaffins and naphthenes in the C 9-C 12 range. RCB can be used as a blending stream for premium quality petroleum products or base stock for developing lubricant formulations. Demand is also growing for biodegradable petroleum distillates of low toxicity that are suitable as solvents of paint, cleaners, pesticides, mosquito repellants, printing inks, resins, varnishes, hydrofracturating fluid, etc. The presence of higher aromatic classes (e.g., polycyclic aromatic hydrocarbons, PAH) and benzene, toluene, ethylbenzene, and xylenes (BTEX) is detrimental [3] for health and it may cause cancer due to long-term exposure [4]. Detailed molecular level characterization in terms of PAH, volatile organic contaminants (BTEX), and hydrocarbon class composition becomes important if RCB is to be used for the applications mentioned above. BTEX evaporates quickly into the air, so exposure to petroleum distillates with high BTEX content is not recommended [5]. Various analytical methods are routinely used for the estimation of BTEX but chromatographic techniques are the most popular for detection at low parts per million. Several GC methods have been published [6-8] which measure benzene and other aromatics in middle distillates but cannot be used for trace level estimations except heartcut two-dimensional gas chromatography where compositional analysis is complicated. An ASTM method based on detailed hydrocarbon analysis (DHA) is available (ASTM D6730, 3) which can analyze BTEX in gasoline range samples up to 100 ppm. Trace level estimation of BTEX Abstract A two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOFMS) method was developed for the hydrocarbon class composition analysis and benzene, toluene, ethylbenzene, and xylene (BTEX) estimation of raffinate column bottom (RCB), which is generated as a by-product from linear alkyl benzene (LAB) plants. The molecular level characterization of RCB is important to generate value-added products for the petrochemical industry. GC×GC-TOFMS was found to be an excellent tool for estimation of hydrocarbon class composition (paraffins, naphthenes, monoaromatics, diaromatics, and polyaromatic hydrocarbons) and trace level BTEX in a single run. The hydrocarbon class composition was validated with the standard method based on HPLC (ASTM D6591) and good correlation was obtained. Finally, RCB is anticipated to be a useful nonhazardous safe by-product which could be used further for generating added value.

All rights reserved (including those of translation into other languages). No part of this Abstract Book may be reproduced in any form-by photo-print, microfilm, or any other means-nor transmitted or translated into a machine language without the permission in writing of the publisher. Only single copies of contributions, or parts thereof, may be reproduced for personal use. This Abstract Book was carefully produced in all its parts. Nevertheless, authors, editors and publisher do not warrant the information contained therein to be free of errors. Readers are advised to keep in mind that statements, data, illustrations, procedurals details or other items may inadvertently be inaccurate.

Recently, we developed a photo ionization (PI) ion source as 3 soft ionization technique for a gas chromatography/high resolution time-of-flight mass spectrometer (GC/HR-TOFMS) system. PI is a soft ionization technique that provides good sensitivity and molecular ion information for compounds with ionization energies below the maximum practical photon energy (10.8 eV) of the deuterium lamp used in our current design. GC/PI MS and GCxGC/PI MS is particularly useful for the analysis of hydrocarbons and aromatic compounds and can be more sensitive than field ionization for certain applications. Because GC/HR-TOFMS can easily give exact mass information for all of the ions generated by photoionization, target compound identification can be very selective and the identification of unknowns is facilitated.

This paper evaluates the influence of crude oil (vacuum residue) properties, the processing of fluid catalytic cracking slurry oil, and recycle of hydrocracked vacuum residue diluted with fluid catalytic cracking heavy cycle oil, and the operating conditions of the H-Oil vacuum residue hydrocracking on the quality of the H-Oil liquid products. 36 cases of operation of a commercial H-Oil® ebullated bed hydrocracker were studied at different feed composition, and different operating conditions. Intercriteria analysis was employed to define the statistically meaningful relations between 135 parameters including operating conditions, feed and products characteristics. Correlations and regression equations which related the H-Oil® mixed feed quality and the operating conditions (reaction temperature, and reaction time (throughput)) to the liquid H-Oil® products quality were developed. The developed equations can be used to find the optimal performance of the whole refinery considering th...

This paper evaluates the influence of crude oil (vacuum residue) properties, the processing of fluid catalytic cracking slurry oil, and recycle of hydrocracked vacuum residue diluted with fluid catalytic cracking heavy cycle oil, and the operating conditions of the H-Oil vacuum residue hydrocracking on the quality of the H-Oil liquid products. 36 cases of operation of a commercial H-Oil® ebullated bed hydrocracker were studied at different feed composition, and different operating conditions. Intercriteria analysis was employed to define the statistically meaningful relations between 135 parameters including operating conditions, feed and products characteristics. Correlations and regression equations which related the H-Oil® mixed feed quality and the operating conditions (reaction temperature, and reaction time (throughput)) to the liquid H-Oil® products quality were developed. The developed equations can be used to find the optimal performance of the whole refinery considering th...

This paper evaluates the influence of crude oil (vacuum residue) properties, the processing of fluid catalytic cracking slurry oil, and recycle of hydrocracked vacuum residue diluted with fluid catalytic cracking heavy cycle oil, and the operating conditions of the H-Oil vacuum residue hydrocracking on the quality of the H-Oil liquid products. 36 cases of operation of a commercial H-Oil® ebullated bed hydrocracker were studied at different feed composition, and different operating conditions. Intercriteria analysis was employed to define the statistically meaningful relations between 135 parameters including operating conditions, feed and products characteristics. Correlations and regression equations which related the H-Oil® mixed feed quality and the operating conditions (reaction temperature, and reaction time (throughput)) to the liquid H-Oil® products quality were developed. The developed equations can be used to find the optimal performance of the whole refinery considering th...

 Nitrogen conversion (hydrodenitrogenation -HDN)  Metals removal (hydrodemetallation -HDM)  Oxygen conversion (hydrodeoxygenation -HDO)  Hydrogenation of: -Aromatic saturation (hydrodearomatization -HDA) -Olefins (HYD)  Hydrocracking (HYC)  (Isomerisation, Ring Opening

Figure 5. Example illustrating that the mass measured is concentration independent. Top row is RIC (m/z 207.1394 (C 13 H 19 O 2 )) of OSPW NA standard, concentration range 10-100 mg/kg, bottom row is corresponding mass spectra in the range of m/z 207.10-207.30.

The amount of waste tire generated constantly in the modern society is on a rapid increase due to the world's urbanization, industrialization and population increase. This research was conducted to recover useful products from waste tyre and harness the possibility of using these products as a petrochemical feedstock alternative. Study Design: Conventional pyrolysis was used to produce bio char, bio-oil and bio-gas Place and Duration of Study: The research was carried out in the department of Pure and Industrial Chemistry and Mechanical Engineering Nnamdi Azikiwe University between January 2020 and march 2020 Methodology: Waste tyre was pyrolyzed using a conventional pyrolysis over three different temperature 400,550 and 750 o C. The yield of the oil and char was determined by weight measurement, while that of gas was determined by mass balancing. The oil produced was characterized using GC/MS (gas chromatography/mass spectrometry) Results: The percentage yield of char, oil and gas at 400 o C, 550 o C and 750 o C respectively are 62, 24, 14; 48, 36.2, 15.8 and 42, 40, 18. The statistical analysis of yield gave a p-value of 0.785211 this showed that there is no significant change across the three samples statistically. The GC/MS

Species and hybrids of Eucalyptus are the world's most widely planted hardwood trees. They are cultivated across a wide range of latitudes and therefore environmental conditions. In this context, comprehensive metabolomics approaches have been used to assess how different temperature regimes may affect the metabolism of three species of Eucalyptus, E. dunnii, E. grandis and E. pellita. Young plants were grown for 53 days in the greenhouse and then transferred to growth chambers at 10, 20 or 30°C for another 7 days. In all three species the leaf chlorophyll content was positively correlated to temperature, and in E. pellita the highest temperature also resulted in a significant increase in stem biomass. Comprehensive metabolomics was performed using untargeted GC-MS and LC-MS. This approach enabled the comparison of the relative abundance of 88 polar primary metabolites from GC-MS and 625 semi-polar secondary metabolites from LC-MS. Using PCA, a major effect of temperature was ob...

This paper reviews the history of Chevron Technology Marketing's hydrocracker pretreat catalyst development. The excellent hydrodenitrogenation (HDN) performance on recently developed catalysts is explained by the theory that more Type II active sites lead to better HDN/HDS (hydrodesulfurization) performance.

Today’s refiners are facing a number of challenges to maximize their product at existing condition. Hydro treating of Diesel is one of the most important process in crude oil refineries in which compounds such as sulfur, nitrogen, oxygen and metal are removed and government standards are met. In this work will study on a Hydrotreater using combined refinery streams. Process simulation of Hydrotreater will be carried out by using CHEMCAD (Chemstations).

Body odour consists of different compounds that interact in various ways with textile materials due to differences in their chemical properties. Clothing made from hydrophilic fibres (e.g., cotton) can be more easily laundered, and odorants more effectively removed than those made from hydrophobic fibres (e.g., polyester). Therefore, the purpose of this research was to examine the interactions between textile materials and odorous compounds when washed several times with different detergents. Test fabrics were of both interlock knit structure and either 100% cotton (234 g/m 2) or 100% polyester (224 g/m 2) fibre content. Test compounds were 4-ethyl octanoic acid (octanoic acid) and 2-nonenal (nonenal). Fabric samples were spiked with 10 µL of a solution of octanoic acid (0.1g), nonenal (0.1g) and dichloromethane (solvent) and left to sit for 24 hours. Inoculated samples were washed with either Tide® Free and Gentle detergent or Tide® Febreze Sports detergent. Residual odorants were measured using gas chromatography with flame ionization detector. Headspace analysis of volatiles was conducted using solid-phase micro-extraction (SPME); direct extraction of compounds remaining in fabrics was done using dichloromethane as the solvent. Considering the peak area of odorants, findings show that cotton generally retained and desorbed lesser odorous compounds than polyester did. Interestingly, the non-polar nonenal was difficult to remove from the non-polar hydrophobic polyester by washing, which resulted in higher quantities of nonenal compared with octanoic acid in the headspace. Also, while multiple washes eventually became more efficient in removing odorants from cotton, polyester did not clean as well.

Typically, the products from waste tyre pyrolysis consist of (i) gas fraction (18 – 23 %wt ), (ii) liquid fraction ( 41 – 49 %wt ), and (iii) char fraction ( 38 – 40 %wt ). The liquid amount is considered the highest among those obtained from waste tyre pyrolysis. The improvements of tyre-derived oils (liquid fraction) could be accomplished by increasing mono-aromatics as a result of the reductions in di-aromatics and polyaromatics through hydrogenation and the conversion of terpenes through aromatization. A basic catalyst that has potassium as a cation such as potassium tert-butoxide (K + (CH3)3CO )) can provide hydrogenation and aromatization. KL zeolite is a representative of a solid basic catalyst. It has a pore diameter 0.71 A and 1-dimensional pore structure. Moreover, the 1-dimensional pore structure can align the incoming molecules parallel on the surface of KL, resulting in high yields of hydrogenated products. TwoDimensional Gas Chromatography coupled with Time-of-Flight M...

Introduction The conversion of renewable bio-feedstocks into transportation fuels in order to reduce our dependence on fossil fuels has led to a number of new processes and fuel formulations. For diesel cars, most of the biodiesel presently available is fatty acid methyl esters (FAME) prepared by transesterification of vegetable oils or tallow. However, FAME is not a stable fuel and has poor cold flow properties [1]. Another route to a renewable diesel fuel is to hydrotreat either a pure renewable feed or a mixture hereof with fossil diesel. The conversion of pure vegetable oils was demonstrated already in the 1980's [2, 3] and these reactions may take place over traditional sulfidic hydrotreating catalysts [3]. In the co-processing scheme, triglycerides are converted to alkanes at the same time as the fossil part of the feed is hydrodesulfurized. The hydrotreating process offers a number of advantages both in form of feed flexibility, product characteristics, and compatibility ...

This paper reviews the history of Chevron Technology Marketing's hydrocracker pretreat catalyst development. The excellent hydrodenitrogenation (HDN) performance on recently developed catalysts is explained by the theory that more Type II active sites lead to better HDN/HDS (hydrodesulfurization) performance.

This paper reviews the history of Chevron Technology Marketing's hydrocracker pretreat catalyst development. The excellent hydrodenitrogenation (HDN) performance on recently developed catalysts is explained by the theory that more Type II active sites lead to better HDN/HDS (hydrodesulfurization) performance.

Purpose – Fibre content can influence the intensity of odour that develops within clothing fabrics. However, little is known about how effective laundering is at removing malodours in clothing which differ by fibre type. The purpose of this paper is to investigate whether a selected cotton fabric differed in odour intensity following multiple wear and wash cycles compared to a polyester fabric. Design/methodology/approach – Eight (male and female) participants wore bisymmetrical cotton/polyester t-shirts during 20 exercise sessions over a ten-week trial period. Odour was evaluated via a sensory panel, bacterial populations were counted and selected odorous volatile organic compounds were measured with comprehensive two-dimensional gas chromatography and time-of-flight mass spectrometry detection. Analysis occurred both before and after the final (20th) wash cycle. Findings – Findings showed that laundering was effective in reducing overall odour intensity (p0.001) and bacterial pop...

Due to excellent separation capacity for complex mixtures of chemicals, comprehensive two-dimensional gas chromatography (GC × GC) is being utilized with increasing frequency for metabolomics analyses. This review describes recent advances in GC × GC method development for metabolomics, organismal sampling techniques compatible with GC × GC, metabolomic discoveries made using GC × GC, and recommendations and best practices for collecting and reporting GC × GC metabolomics data.

The use of glues for stone tool hafting is an important innovation in human evolution. Compared to other organic remains, glues are preserved more frequently, though mainly in small spots. Reliable identification requires chemical molecular characterization, which is tra- ditionally performed by gas chromatography – mass spectrometry (GC–MS). Current methods of extraction and derivatization prior to GC–MS are destructive and require relatively large samples, which is problematic for prehistoric glue residues. In this paper, we discuss the results of an experimental study using a new method (HS-SPME GC×GC–HRTOFMS) that proves effective for identifying small quantities of compound glues. The method is non-destructive with an improved sensitivity in comparison to traditional GC–MS, and it has a high potential for prehistoric samples.

— It has been carried out the copolymerization reactions of hexene-1 and indene with participation of BF 3 ·O(C 2 H 5) 2 as the catalyst, the yield, the composition, the structure, the copolymerization constant and the average molecular weight values depending on cooligomerization condition have been determined. It has been shown that a location of links in the prepared cooligomers has a statistic character, but the blocks organized by molecules of hexene-1 may be included. Thermal stability of the synthesized cooligomers of hexene-1-indene has been investigated both individually and in fatty solution and it has been elucidated that an increase of a quantity of indene links in cooligomer composition leads to increase of thermal stability and an increase of the molecular weight decreases a thermal stability. An inclusion of the synthesized cooligomers in composition of M-6 oil as synthetic component increases a viscosity index value and gives it anticorrosion property.

Large volumes of oil sands process-affected water (OSPW) are produced in northern Alberta by the surface mining oil sands industry. Naphthenic acids (NAs) are a complex mixture of persistent organic acids that are believed to contribute to the toxicity of OSPW. In situ microbial biodegradation strategies are slow and not effective at eliminating chronic aquatic toxicity, thus there is a need to examine alternative remediation techniques. NAs with multiple rings and alkyl branching are most recalcitrant to microbial biodegradation, but here we hypothesized that these same structural features may lead to preferential degradation in the ozonation process. Total NA degradation increased with increasing pH for commercial NA solutions, suggesting a hydroxyl radical mechanism and that naturally alkaline OSPW would unlikely require pH adjustment prior to treatment. For commercial NAs and OSPW, NAs with more rings and more carbon (and more H atoms) were depleted most rapidly in the process. Relative rate measurements with binary mixtures of model NA compounds not only confirmed this structure reactivity but also indicated that alkyl branching patterns were an additional factor determining NA reactivity. The results demonstrate that ozonation is complementary to microbial biodegradation, and the process remains a promising water reclamation strategy for the oil sands industry.

Human axillary sweat is a poorly explored biofluid within the context of metabolomics when compared to other fluids such as blood and urine. In this paper, we explore the volatile organic compounds emitted from two different types of fabric samples (cotton and polyester) which had been worn repeatedly during exercise by participants. Headspace solid-phase microextraction (SPME) and comprehensive two-dimensional gas chromatography time-of-flight mass spec-trometry (GC×GC-TOFMS) were employed to profile the (semi)volatile compounds on the fabric. Principal component analysis models were applied to the data to aid in visualizing differences between types of fabrics, wash treatment, and the gender of the subject who had worn the fabric. Statistical tools included with commercial chromatography software (ChromaTOF) and a simple Fisher ratio threshold-based feature selection for model optimization are compared with a custom-written algorithm that uses cluster resolution as an objective function to maximize in a hybrid backward-elimination forward-selection approach for optimizing the chemometric models in an effort to identify some compounds that correlate to differences between fabric types. The custom algorithm is shown to generate better models than the simple Fisher ratio approach.