Research
A look into the approach, themes, and analytical tools of the Mabury Group.

Approach and Themes

The Mabury research team is interested in elucidating the mechanisms and pathways that control the environmental fate, dissipation, and persistence of organic halogenated pollutants. We are specifically interested in understanding how the presence of halogen atoms in chemical architecture may affect the physical and chemical properties of these organohalogen chemicals, both of which have implications for their reactivity and persistence in the natural environment

We have been fascinated by the dichotomy between some perfluorinated compounds which have been shown to redefine ‘persistence’ with no observable degradation under even extreme conditions, and other fluorinated compounds that are rapidly biotransformed in various biological systems. We are actively engaged in a large number of experiments in the area of fluorinated surfactants and polymers and their analytical, fate, disposition, toxicity, and persistence chemistry. Examples of such experiments include: aerobic and anaerobic incubation with wastewater treatment plant (WWTP) media to investigate biodegradation; animal exposure (i.e. rats and fish) to assess bioaccumulation and biotransformation; in vitro reactions with biological constituents (i.e. amino acids, proteins, enzymes) to evaluate kinetics and binding mechanisms; and method development and monitoring of field-collected environmental samples (i.e. human blood, surface waters, sediments, WWTP sludge, etc.). Field sampling also plays a key role in our understanding of the global contamination of these fluorinated pollutants. Past field campaigns have taken place in Resolute Bay and Devon Island in the Arctic.

We also maintain interests in other chemical pollutants such as the mixed halogenated dioxins. Ongoing experiments investigate the formation of mixed halogenated species under thermal conditions, while new analytical methods are developed for their identification in environmental samples.

Students working in this research group typically synthesize new compounds for use as standards or to confirm identity of proposed reaction metabolites. We endeavour to glean the techniques from all areas of chemistry to apply to our investigations and are not wedded to any one technique to approach our hypotheses or objectives. Students directly benefit from this interdisciplinary approach by learning disparate chemical skills and communicating across discipline boundaries. These projects require students to learn the latest spectroscopic, chromatographic, and mass spectrometric instrumentation techniques which is greatly facilitated by the wealth of instrumentation we have for our research (both in our lab and in AIMS and ANALEST).

We are also interested in chemical education in the context of analytical and environmental chemistry and most of the grad students have been involved in new pedagogical projects that have been published in the Journal of Chemical Education.


Crawford Lake - CHM 410F/1410F Field Sampling Site

Waters Xevo TQ-S

Instrumentation

Fluorine-19 is a 100% abundant dipolar nucleus which gives good sensitivity for NMR applications. Recently, the department acquired three new Agilent NMR spectrometers, ranging from 500-700 MHz. The 700 MHz spectrometer is the highest field we now possess and will be equipped with a state of the art probe specifically for 19F detection. This probe will have almost no background noise and when combined with the very high field strength, greatly improves the overall signal to noise. This will allow environmental samples to be analyzed directly without the need for preconcentration or extensive sample cleanup. Our current efforts are focused on developing 19F NMR as a selective analytical technique for detection, characterization, and quantitation of fluorinated organic compounds in air, water, and soil samples. We also use 19F NMR as a powerful tool for determining degradation pathways and identifying novel structures.

Many of the chemistries we now investigate involve a broad range of analytes that differ in volatility, polarity, and charge. The Mabury research lab is currently home to a suite of powerful analytical instruments that are capable of low detection limits for trace analysis and sample flexibility for analysis of solids, liquids, and gases.

3 gas chromatograph-mass spectrometers (GC-MS)
  • 2 Agilent 7890 GC systems equipped with Agilent 5795 inert MS (both EI and CI sources are available)
  • 1 Agilent 6890 GC system equipped with Agilent 5973 MS (coupled to in-house designed cryofocuser for sampling novel airborne fluorinated contaminants)
2 ultra-high pressure liquid chromatograph-tandem mass spectrometers (UPLC-MS/MS
  • 1 Waters Acquity UPLC system coupled to AB/Sciex API4000 MS/MS
  • 1 Waters Acquity UPLC system coupled to Waters Xevo TQS MS/MS (currently considered one of the best in the market in terms of sensitivity and robustness)
Total organofluorine analyzer coupled to a combustion ion chromatograph (TOF-CIC)
  • Used to measure total organic and inorganic fluorine content in a sample
  • Sample is sent to a combustion furnace in which all organic and/or inorganic fluorine is converted to hydrogen fluoride; fluoride content measured by ion chromatography
  • AQF-100 combustion furnace (Mitsubishi Chemical, Japan) coupled to ICS-2100 ion chromatograph (Dionex Co. Ltd., USA)