Non-targeted screening workflows for gas chromatography – high-resolution mass spectrometry analysis to find and identify biomagnifying contaminants in biota samples

The health of key species in the Baltic region has been affected by exposure to anthropogenic hazardous substances (AHSs), which accumulate in organisms and are transferred through food chains. Therefore, there is a need for comprehensive characterization of the occurrence and accumulation of AHSs in the ecosystem. In this study, we use a non-target screening (NTS) approach for this purpose. A major challenge in NTS of biological samples is the removal of matrix components, like lipids that may interfere with the detection and identification of analytes. We combine size separation by gel permeation chromatography with polarity separation by adsorption chromatography to achieve sufficient lipid removal for gas chromatography – mass spectrometry analysis. In addition, we present new data processing workflows designed to systematically find and identify frequently occurring and biomagnifying AHSs. Using these workflows, we discovered a wide range of contaminants in marine biota samples and calculated their biomagnification factors (BMFs). Compounds with BMFs above one included legacy chlorinated pollutants (e.g., PCBs), polybrominated diphenyl ethers, and brominated biphenyls. There were also several halogenated natural products, the novel flame retardant Dechlorane 602, and other emerging contaminants. The legacy pollutants exhibited the expected biomagnification behavior, demonstrating the utility of the data processing workflow.