Characterization of Persistent Organic Pollutants in Sediment using Enhanced Chromatography with High-Resolution Mass Spectrometry

Emerging Environmental Applications for High Resolution Mass Spectrometry
Oral Presentation

Prepared by D. Alonso1, G. Tomy2, N. Vitharana3, E. Macturk1, J. Binkley1
1 - LECO Corporation, LECO ESW, 3024 Veronica, St. Joseph, Michigan, 49085, United States
2 - University of Manitoba, Department of Chemistry, 144 Dysart Rd., Winnipeg, Manitoba, R3T2N2, Canada
3 - University of Mannitoba, Department of Chemistry, University of Mannitoba, 144 Dysart Rd., Manitoba, Winnipeg, Canada


Contact Information: [email protected]; 269-983-5817

ABSTRACT

Persistent organic pollutants (POPs) in sediments pose significant ecological and human health risks due to their toxicity, persistence, and bioaccumulative behavior. Compounds such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and chlorinated phenols originate from industrial activities, combustion processes, and improper waste disposal. Once deposited, these contaminants can persist for decades, serving as long-term sources of exposure to benthic organisms and higher trophic levels through food web transfer. Associated adverse effects include carcinogenicity, endocrine disruption, immunotoxicity, and impaired reproduction, underscoring the need for improved monitoring and characterization of sediment-associated POPs.
In this study, sediment samples were analyzed using comprehensive two-dimensional gas chromatography coupled with high-resolution time-of-flight mass spectrometry (GC×GC HRTOFMS). Samples were solvent extracted, filtered, concentrated, and reconstituted in hexane before analysis. Extracts were separated using GC×GC and detected using HRTOFMS equipped with a multi-mode ion source. Electron ionization (EI) data were processed using untargeted workflows, including peak detection and spectral library matching. Complementary chemical ionization data supported compound characterization.
The combination of enhanced chromatographic separation and high-resolution mass spectrometry significantly increased the number of annotated pollutants. Non-targeted data processing facilitated the characterization of multiple hazardous chemical classes, including PAHs, PCBs, heteroatom-containing PAHs (oxygen , nitrogen , and sulfur substituted), chlorinated and brominated phenols, and linear alkyl benzenes. Compound annotation integrated spectral library searching with elemental formula assignment based on high-resolution, accurate mass measurements of fragment, molecular, and adduct ions (average mass accuracy ≤ 1 ppm; isotopic fidelity scores > 900/1000). Retention index filtering and the integration of soft ionization with EI spectra improved confidence in identifications. Target Analyte Find processing and Spectral Analysis Tools were further applied to characterize trace-level POPs in sediment samples.