ARS | Publication request: Multi-class, multi-residue analysis of pesticides, polychlorinated biphenyls, polycyclic aromatic hydrocarbons, polybrominated diphenyl ethers and novel flame retardants....mass spectrometry

Submitted to: Analytica Chimica Acta
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 22, 2012
Publication Date: January 3, 2013
Citation: Sapozhnikova, Y.V., Lehotay, S.J. 2013. Multi-class, multi-residue analysis of pesticides, polychlorinated biphenyls, polycyclic aromatic hydrocarbons, polybrominated diphenyl ethers and novel flame retardants....mass spectrometry. Analytica Chimica Acta. 758:80-92.

Interpretive Summary: Novel flame retardants are emerging food contaminants of interest as due to their toxicology, persistence in the environment, and bioaccumulation / biomagnification in the food chain. Catfish have become of particular interest to USDA-FSIS due to recent changes in legislation. To achieve low cost, highly selective and sensitive monitoring of a wide scope of contaminants in fish and seafood with high sample throughput, we developed and evaluated a laboratory-based multi-class, multi-residue method for analysis of several classes of environmental contaminants, including emerging flame retardants, representative pesticides, and other persistent organic pollutants identified by the Stockholm Convention. The new method is based on QuEChERS sample preparation coupled to low-pressure gas chromatography-tandem mass spectrometry (LP-GC/MS-MS) for improved analysis of over 60 contaminants simultaneously. The generated data on occurrence of these contaminants in foods may advance the understanding of the potential risk posed by these emerging chemicals and aid in future risk assessment and regulations.

Technical Abstract: A multi-class, multi-residue method for the analysis of 13 novel flame retardants, 18 representative pesticides, 14 polychlorinated biphenyl (PCB) congeners, 16 polycyclic aromatic hydrocarbons (PAHs), and 7 polybrominated diphenyl ether (PBDE) congeners in catfish muscle was developed and evaluated using fast low pressure gas chromatography triple quadrupole tandem mass spectrometry (LP-GC/MS-MS). The method was based on a QuEChERS extraction with acetonitrile and dispersive solid-phase extraction (d-SPE) clean-up with zirconium-based sorbent prior to LP-GC/MS-MS analysis. The developed method was evaluated at 4 spiking levels and further validated by analysis of NIST Standard Reference Materials (SRMs) 1974B and 1947. Sample preparation for a batch of 10 homogenized samples took about 1 h/analyst, and LP-GC/MS-MS analysis provided fast separation of multiple analytes within 9 min achieving high throughput. With the use of isotopically-labeled internal standards, recoveries of all but one analyte were between 70 and 120% with relative standard deviations less than 20% (n=5). The measured values for both SRMs agreed with certified/reference values (72-119% accuracy) for the majority of analytes. The detection limits were 0.1-0.5 ng/g for PCBs, 0.5-10 ng/g for PBDEs, 0.5-5 ng/g for select pesticides and PAHs and 1-10 ng/g for flame retardants. The developed method was successfully applied for analysis of catfish samples from the market.