Profiling of individual naphthenic acids at a composite tailings reclamation fen by comprehensive two-dimensional gas chromatography-mass spectrometry.

Naphthenic acids (NAs) are naturally occurring in the Athabasca oil sands region (AOSR) and accumulate in tailings as a result of water-based extraction processes. NAs exist as a complex mixture, so the development of an analytical technique to characterize them has been an on-going challenge. The aim of this study was to use comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry to monitor individual NAs within a wetland reclamation site in the AOSR.

Improved coverage of naphthenic acid fraction compounds by comprehensive two-dimensional gas chromatography coupled with high resolution mass spectrometry.

This study reports the first application of comprehensive two-dimensional gas chromatography coupled to a high-resolution quadrupole time-of-flight mass spectrometer (GC×GC/HRQTOF-MS) for the characterization of naphthenic acid fraction compounds (NAFCs) from the Alberta Oil Sands. High resolution mass spectrometry (HRMS) significantly increased the coverage of NAFCs in the mixture and allowed the differentiation of NAFCs from several chemical classes. It was demonstrated that GC×GC, in combination with the high mass accuracy and precision of the HRQTOF-MS, could distinguish chemical species with the C vs SH mass split at a much lower resolving power than required with direct infusion experiments.

Application of a comprehensive extraction technique for the determination of poly- and perfluoroalkyl substances (PFASs) in Great Lakes Region sediments.

A comprehensive method to extract perfluoroalkane sulfonic acids (PFSAs), perfluoroalkyl carboxylic acids (PFCAs), polyfluoroalkyl phosphoric acid diesters (diPAPs), perfluoroalkyl phosphinic acids (PFPiAs) and perfluoroalkyl phosphonic acids (PFPAs) from sediment and analysis by liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed and applied to sediment cores from three small isolated lakes (Plastic Lake, Lake 442, Lake Tettegouche) and Lake Ontario in the Great Lakes Region. Recoveries of the target compounds using the optimized acetonitrile/sodium hydroxide extraction ranged from 73% to 120%. The greatest concentrations of per- and polyfluorinated alkyl substances (PFASs) were recorded in sediment from Lake Ontario (ΣPFASs 13.

Age-associated metabolic dysregulation in bone marrow-derived macrophages stimulated with lipopolysaccharide.

Macrophages are major contributors to age-associated inflammation. Metabolic processes such as oxidative phosphorylation, glycolysis and the urea cycle regulate inflammatory responses by macrophages. Metabolic profiles changes with age; therefore, we hypothesized that dysregulation of metabolic processes could contribute to macrophage hyporesponsiveness to LPS.

Evaluation of Firefighter Exposure to Wood Smoke during Training Exercises at Burn Houses.

Smoke from wood-fueled fires is one of the most common hazards encountered by firefighters worldwide. Wood smoke is complex in nature and contains numerous compounds, including methoxyphenols (MPs) and polycyclic aromatic hydrocarbons (PAHs), some of which are carcinogenic. Chronic exposure to wood smoke can lead to adverse health outcomes, including respiratory infections, impaired lung function, cardiac infarctions, and cancers.