Nathan Oldridge: Chemistry Career


  • Graduated with Masters of Science from the University of Toronto, Department of Chemistry.
  • 6 papers published in peer-reviewed journals
  • View my thesis online here ("Halogen Activation from Sea Ice: Nitrate Photolysis and Heterogenous Reaction with Ozone")
  • I also have an Honours Bachelor of Science in Chemistry.

Oxidizing Br-(aq) to Br2(g) with O3(g)

Most Recently, I worked with Prof. J. Abbatt at the University of Toronto to study the generation of gas-phase halogens (Br2 in particular) from sea ice.

We investigated nitrate photolysis as an in-situ source of OH radicals within the ice, and found that these oxidize bromide to form gas-phase Br2. We also observed the formation of gas-phase nitrogen oxides. We also quantified a heterogeneous reaction between gas-phase ozone and bromide in sea ice, by determining the reactive uptake coefficient and how it varied with temperature, concentration and other factors. We found (and quantified) the relative contributions of the liquid- and solid-phase components to the overall reaction.

Stop-Flow GC×GC

From 2006 to 2007, I worked with Prof. T. Gorecki on a Dean's-switch-based stop-flow apparatus for comprehensive two-dimensional gas chromatography (GCxGC).

This type of stop-flow device works by applying gas pressure at the junction between the first and second columns (near the modulator). This stops flow in the first column while allowing the secondary separation to proceed in the second column. Dr. Gorecki already had the instrumentation and knowledge required; my purpose was to test it and verify that it enhanced separation power. It did.

Gas-phase Amino Acid Equilibria

Also in 2006, I worked with Prof. T. McMahon and his research group to investigate several different gas-phase equilibria.

Our original purpose was to investigate the affinity of short alcohol molecules (methanol and ethanol) to gas-phase amino acids. Over the course of the summer, we also investigated HNF2 and toyed with the idea of forming gas-phase zwitterions.


  • Formation of Gas-Phase Bromine from Interaction of Ozone with Frozen and Liquid NaCl/NaBr Solutions: Quantitative Separation of Surficial Chemistry from Bulk-Phase Reaction Status: Published in J. Phys. Chem. A, Volume 115, Issue 12, 2011, pp. 2590–2598 (Link)
  • Release of Gas-Phase Halogens by Photolytic Generation of OH in Frozen Halide-Nitrate Solutions: An Active Halogen Formation Mechanism? Status: Published in J. Phys. Chem. A, Volume 114, Issue 23, 2010, pp. 6527–6533 (Link)
  • Investigations of Strong Hydrogen Bonding in (ROH)n--FHF- (n=1, 2 and R=H, CH3, C2H5) Clusters via High Pressure Mass Spectrometry and Quantum Calculations Status: Published in J. Phys. Chem. A, Volume 113, Issue 4, 2009, pp. 644–652. (Link)
  • Stop-Flow Comprehensive Two-Dimensional Gas Chromatography with Pneumatic Switching Status: Published in J. Sep. Sci. Vol. 31, Issue 19, 2008, pp. 3375-3384. (Link)
  • Strong and Very Strong Hydrogen Bonding in Fluoro-amine - Fluoride Systems Status: Published in Int. J. Mass Spec., Volume 267, Issue 1-3, 2007, pp. 338-345. (Link)
  • Recent Advances in Comprehensive Two-Dimensional Gas Chromatography (GC×GC) Status: Published in J. Liq. Chrom. Rel. Technol., Volume 29, Issue 7-8, 2006, pp. 1077-1104. (Link)

Posters [Partial List]

  • Halogen Activation in Frozen Seawater by Nitrate Photolysis and Reaction with Ozone Oldridge, N.; Symington, A.; Sjostedt, S.; Abbatt, J. 2008 AGU Fall Meeting, San Francisco, California, USA, December 15-19, 2008. (Link to poster)

Presentations [Partial List]

  • Halogen Activation from Frozen Sea Water Initiated by Uptake of Ozone and Hydroxyl Radicals and by Photolysis of Nitrate J. Abbatt, R.A. Cox, S. Gao, N. Oldridge, S. Sjostedt, A. Symington 2009 AGU Fall Meeting, San Francisco, California, USA, December 14-18, 2009. (Link to Abstract)
  • Photo-Induced Release of Halogens from Frozen Salt Solutions Oldridge, N.; Sjostedt, S.; Symington, A.; Abbatt, J. 2008 Environmental Chemistry Colloquium, University of Toronto, Canada, June 9-12, 2008.
  • Comprehensive Two-Dimensional Gas Chromatography (GCxGC) with a Dean's switch-based stop-flow apparatus. Oldridge, N.; Panic, O.; Gorecki, T. 35th Southern Ontario Undergraduate Student Chemistry Conference (SOUSCC), University of Ontario Institute of Technology, Oshawa, Canada, March 17, 2008. (Link to Bulletin in UWaterloo News) - This presentation won 3rd Prize in the Analytical, Environmental and Forensic Chemistry Session