Molecular profiling of naphthenic acids in technical mixtures and oil sands process-affected water using polar reversed-phase liquid chromatography-mass spectrometry.
In this work, a reversed-phase ultra-HPLC (UHPLC) ultrahigh resolution MS (UHRMS) method was evaluated for the comprehensive profiling of NAs containing two O atoms in each molecule (O2NAs; general formula CnH2n + zO2, where n is the number of carbon atoms and z represents hydrogen deficiency). Using a polar cyanopropyl-bonded phase column and negative-ion electrospray ionization mass spectrometric detection at 120,000 FWHM (m/z 400), 187 and 226 O2NA species were found in two naphthenic acid technical mixtures, and 424 and 198 species with molecular formulas corresponding to O2NAs were found in two oil sands process-affected water samples (one from a surface mining operation and the other from a steam-assisted gravity drainage operation), respectively. To our knowledge, these are the highest numbers of molecular compositions of O2NAs that have been profiled thus far in environmental samples. Assignments were based on accurate mass measurements (≤3 ppm) combined with rational molecular formula generation, correlation of chromatographic behavior of O2NA homologues with their elemental compositions, and confirmation with carboxyl group-specific chemical derivatization using 3-nitrophenylhydrazine. Application of this UHPLC-UHRMS method to the quantitation of O2NAs in the surface mining operation-derived water sample showed excellent linearity (R2= 0.9999) with external calibration, a linear range of 256-fold in concentration, and quantitation accuracies of 64.9 and 69.4% at two "standard substance" spiking levels.
University of Victoria-Genome British Columbia Proteomics Centre, Vancouver Island Technology Park, Victoria, British Columbia, Canada.
Jun
J
Han
Alberta Innovates-Technology Futures, Vancouver Island Technology Park, Victoria, British Columbia, Canada.
Yi
Y
Yi
University of Victoria-Genome British Columbia Proteomics Centre, Vancouver Island Technology Park, Victoria, British Columbia, Canada.
Karen
K
Lin
Alberta Innovates-Technology Futures, Calgary, Alberta, Canada.
S Jean
SJ
Birks
Alberta Innovates-Technology Futures, Vancouver Island Technology Park, Victoria, British Columbia, Canada.
John J
JJ
Gibson
University of Victoria-Genome British Columbia Proteomics Centre, Vancouver Island Technology Park, Victoria, British Columbia, Canada.|Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia, Canada.
Christoph H
CH
Borchers
D002264:Carboxylic Acids / Q000032:analysis* / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D056148:Chromatography, Reverse-Phase / Q000379:methods*; D007220:Industrial Waste; D013058:Mass Spectrometry / Q000379:methods*; D061329:Oil and Gas Fields; D062065:Wastewater / Q000032:analysis* / Q000737:chemistry
D002264:Carboxylic Acids; D007220:Industrial Waste; D062065:Wastewater; C046170:naphthenic acid
Naphthenic acid; Oil sands process-affected water; Polar cyanopropyl-bonded phase column; Ultra-HPLC ultrahigh resolution mass spectrometry