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United States Department of Agriculture

Agricultural Research Service

Research Project: TECHNOLOGIES FOR THE DETECTION OF CHEMICAL AND BIOLOGICAL CONTAMINANTS IN FOODS

Location: Residue Chemistry and Predictive Microbiology

Title: Rapid sample preparation and fast GC-MS/MS for the analysis of pesticides and environmental contaminants in fish

Author
item Sapozhnikova, Yelena

Submitted to: LC GC North America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 18, 2014
Publication Date: N/A

Interpretive Summary: In this study we compared efficiency of the three sorbents for d-SPE clean-up of fish extracts for the analysis of pesticides and environmental contaminants: C18+PSA, Z-Sep and Z-Sep Plus. C18+PSA removed the highest amounts of co-extractive materials by weight (80%), followed by Z-Sep (66%) and Z-Sep Plus (55%). In terms of recoveries of target analytes, Z-sep provided the highest recoveries for most of the contaminants, and Z-sep Plus showed greatest standard deviations, perhaps, caused by matrix interferences. Recoveries of analytes not normalized to ISTDs, were 2-3 times lower for all classes, except for pesticides, reflecting the loss of the corresponding ISTDs during the sample preparation. Two major co-extractive compounds identified in the extracts that contributed to MEs were oleic and octadecanoic acid, and d-SPE with Z-Sep removed these compounds most effectively. Peak shapes and widths were altered by co-eluting matrix interferences as we observed in the case of o,p’-DDE. Calculated MEs for TPP and o,p’-DDE based on peak areas were lowest for d-SPE with C18+PSA, followed by Z-Sep and Z-Sep Plus, however they were less than 3% for all the treatments when normalized to ISTDs, indicating the need of using ISTD for ME compensation. Finally, Pearson correlations were reported for compounds’ recoveries, tR and log Kow values.

Technical Abstract: A rapid high-throughput analytical method for the simultaneous determination of pesticides and environmental contaminants, including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and flame retardants (FRs) in fish was developed and evaluated. The method was based on QuEChERS (quick, easy, cheap, effective, rugged, safe) technique with acetonitrile extraction, and a dispersive solid phase extraction (d-SPE) clean-up. Three sorbent combinations were compared for clean-up efficiency and recoveries of the contaminants: C18+PSA, traditionally used for lipid removal in d-SPE, and two novel zirconium oxide based sorbents for phospholipids removal – Z-Sep and Z-sep Plus. d-SPE with Z-Sep provided the best clean-up efficiency with the lowest baseline, as well as satisfactory recoveries (70-120% calculated based on isotope labeled internal standards) for the most analytes. The method allows for quick sample preparation of fish samples for the analysis of almost 200 targeted contaminants using fast low pressure GC-MS/MS, thus providing a wide scope of analysis.

Last Modified: 9/1/2014
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