title: Comprehensive analysis of oil sands processed water by direct-infusion Fourier-transform ion cyclotron resonance mass spectrometry with and without offline UHPLC sample prefractionation.
abstract: Oil sands processed water (OSPW) is the main byproduct of the large-scale bitumen extraction activity in the Athabasca oil sands region (Alberta, Canada). We have investigated the acid-extractable fraction (AEF) of OSPW by extraction-only (EO) direct infusion (DI) negative-ion mode electrospray ionization (ESI) on a 12T-Fourier transform ion cyclotron resonance mass spectrometer (FTICR-MS), as well as by offline ultrahigh performance liquid chromatography (UHPLC) followed by DI-FTICR-MS. A preliminary offline UHPLC separation into 8 fractions using a reversed-phase C4 column led to approximately twice as many detected peaks and identified compounds (973 peaks versus 2231 peaks, of which 856 and 1734 peaks, respectively, could be assigned to chemical formulas based on accurate mass measurements). Conversion of these masses to the Kendrick mass scale allowed the straightforward recognition of homologues. Naphthenic (CnH2n+zO2) and oxy-naphthenic (CnH2n+zOx) acids represented the largest group of molecules with assigned formulas (64%), followed by sulfur-containing compounds (23%) and nitrogen-containing compounds (8%). Pooling of corresponding fractions from two consecutive offline UHPLC runs prior to MS analysis resulted in ~50% more assignments than a single injection, resulting in 3-fold increase of identifications compared to EO-DI-FTICR-MS using the same volume of starting material. Liquid-liquid extraction followed by offline UHPLC fractionation thus holds enormous potential for a more comprehensive profiling of OSPW, which may provide a deeper understanding of its chemical nature and environmental impact.
authors.affiliation: University of Victoria - Genome British Columbia Proteomics Centre, Vancouver Island Technology Park, #3101 - 4464 Markham Street, Victoria, BC V8Z 7X8, Canada.
authors.forename: Adrien
authors.initials: A
authors.lastname: Nyakas
authors.forename: Jun
authors.initials: J
authors.lastname: Han
authors.forename: Kerry M
authors.initials: KM
authors.lastname: Peru
authors.forename: John V
authors.initials: JV
authors.lastname: Headley
authors.forename: Christoph H
authors.initials: CH
authors.lastname: Borchers
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D017357:Cyclotrons; D010578:Petroleum; D012822:Silicon Dioxide; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*
chemical_list: D010578:Petroleum; D012822:Silicon Dioxide