Food Safety and Environmental Stewardship Program

We developed two independent approaches for separation and quantitation of 24 oxygenated polycyclic aromatic hydrocarbons (OPAHs) using both liquid chromatography-atmospheric pressure chemical ionization/mass spectrometry (LC-APCI/MS) and gas chromatography-electron impact/mass spectrometry (GC-EI/MS). Building on previous OPAH research, we examined laboratory stability of OPAHs, improved existing method parameters, and compared quantification strategies using standard addition and an internal standard on an environmental sample. Of 24 OPAHs targeted in this research, 19 compounds are shared between methods, with 3 uniquely quantitated by GC-EI/MS and 2 by LC-APCI/MS. Using calibration standards, all GC-EI/MS OPAHs were within 15 % of the true value and had less than 15 % relative standard deviations (RSDs) for interday variability. Similarly, all LC-APCI/MS OPAHs were within 20 % of the true value and had less than 15 % RSDs for interday variability. Instrument limits of detection ranged from 0.18 to 36 ng mL(-1) on the GC-EI/MS and 2.6 to 26 ng mL(-1) on the LC-APCI/MS. Four standard reference materials were analyzed with each method, and we report some compounds not previously published in these materials, such as perinaphthenone and xanthone. Finally, an environmental passive sampling extract from Portland Harbor Superfund, OR was analyzed by each method using both internal standard and standard addition to compensate for potential matrix effects. Internal standard quantitation resulted in increased precision with similar accuracy to standard addition for most OPAHs using 2-fluoro-fluorenone-(13)C as an internal standard. Overall, this work improves upon OPAH analytical methods and provides some considerations and strategies for OPAHs as focus continues to expand on this emerging chemical class.