title: Exploring the complexity of oil sands process-affected water by high efficiency supercritical fluid chromatography/orbitrap mass spectrometry.
abstract: BACKGROUND
  Approximately 1 billion m(3) of oil sands process-affected water (OSPW) is currently stored in tailings ponds in Northern Alberta, Canada. The dissolved organic compounds in OSPW have been termed a supercomplex mixture of bitumen-derived substances and continuing efforts to understand its underlying chemical composition are important for evaluating its environmental hazards.
  
  
  METHODS
  Packed column supercritical fluid chromatography (SFC) was applied to OSPW analysis for the first time. By combining four columns in series (each 25 cm × 4.6 mm I.D., 5.0 µm bare silica) approximately 80,000 plates were achieved on a 1 m column. Using a simple fixed restrictor, the SFC eluent was coupled directly to ultrahigh-resolution orbitrap mass spectrometry (SFC/Orbitrap-MS).
  
  
  RESULTS
  SFC/Orbitrap-MS, with positive and negative atmospheric pressure chemical ionization (APCI +/-), revealed the partial or full chromatographic separation of isomers for a wide array of chemical species, including naphthenic acids (Cn H2n + Z O2 ) and unknown sulfur- and nitrogen-containing molecules. For smaller compounds (e.g. naphthenic acids where n ≤10), or for larger structurally constrained compounds (e.g. C16 naphthenic acid with 9 double-bond equivalents), apparent baseline resolution of many isomers was possible. Isomer-specific MS/MS experiments furthermore allowed characterization of functional groups in novel species. For example, in APCI+ mode, up to 16 isomers of C6 H11 ON were revealed to have amide and amino functionalities.
  
  
  CONCLUSIONS
  This combination of high efficiency chromatography and ultra-high mass resolution detection resulted in a powerful method with capabilities for characterizing or 'fingerprinting' unknown species with little interference. The method has great promise for environmental monitoring and forensics in the oil sands region, as well as for further studies on the composition of dissolved organic compounds in OSPW.
authors.affiliation: Division of Analytical & Environmental Toxicology, Department of Laboratory Medicine & Pathology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, T6G 2G3, Canada.
authors.forename: A S
authors.identifier: http://orcid.org/0000-0003-3940-5913
authors.initials: AS
authors.lastname: Pereira
authors.affiliation: Division of Analytical & Environmental Toxicology, Department of Laboratory Medicine & Pathology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, T6G 2G3, Canada.
authors.forename: J W
authors.initials: JW
authors.lastname: Martin
mesh_terms: D002264:Carboxylic Acids / Q000032:analysis*; D025924:Chromatography, Supercritical Fluid / Q000379:methods; D004784:Environmental Monitoring / Q000379:methods; D013058:Mass Spectrometry / Q000379:methods; D017672:Nitrogen Compounds / Q000032:analysis*; D061329:Oil and Gas Fields / Q000737:chemistry*; D013457:Sulfur Compounds / Q000032:analysis*; D014867:Water / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D002264:Carboxylic Acids; D017672:Nitrogen Compounds; D013457:Sulfur Compounds; D014874:Water Pollutants, Chemical; D014867:Water; C046170:naphthenic acid