Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/16/2015
Publication Date: 2/16/2015
Citation: Sapozhnikova, Y.V., Lehotay, S.J. 2015. Evaluation of different parameters in the extraction of incurred pesticides and environmental contaminants in fish. Journal of Agricultural and Food Chemistry. DOI:10.1021/jf505651g.
Interpretive Summary: Sample processing is often ignored during analytical method development and validation, but accurate results for real samples depend on all aspects of the analytical process. In this study, we monitored 207 diverse pesticide and environmental contaminants in real-world salmon, white croaker, and a standard reference material (Lake Michigan fish tissue) using 3 extraction devices (vibration shaker, pulsed-vortexer, and probe blender) for different lengths of time, subsample size, and solvent ratio using the “quick, easy, effective, rugged, and safe” (QuEChERS) method. Our results showed that 1 min extraction with the pulsed-vortexing shaker was sufficient for extraction of the 35 incurred contaminants detected in the fish, and 2 g subsamples were adequate for analysis. Smaller subsample size often translates into faster, easier, and less wasteful methods, provided that the subsample adequately represents the original sample. This study demonstrated the real-world applicability of a highly streamlined and effective qualitative and quantitave method of analysis, and it is expected to be implemented widely throughout the world to monitor contaminants in seafood and other sample types.
Technical Abstract: Sample processing is often ignored during analytical method development and validation, but accurate results for real samples depend on all aspects of the analytical process. Also, validation is often conducted only using spiked samples, but extraction yields may be lower in incurred samples. In this study, different variables in extraction for incurred pesticides and environmental contaminants in fish were investigated. Among 207 analytes screened using low-pressure gas chromatography–tandem mass spectrometry, consisting of 150 pesticides, 15 polycyclic aromatic hydrocarbons (PAHs), 14 polychlorinated biphenyls (PCBs), 6 polybrominated diphenyl ethers (PBDEs), and 22 other flame retardants (FRs), 35 (16 pesticides, 9 PCBs, 5 PBDEs, and 5 PAHs) were identified for quantification in samples of salmon, croaker, and NIST Standard Reference Material 1947 (Lake Michigan Fish Tissue). Extraction efficiencies using different extraction devices (blending, vortexing, and vibrating) vs. time, sample size, and sample/solvent ratio were determined. In comparison to blending results, use of a pulsed-vortexer for 1 min with 1/1 (g/mL) sample/acetonitrile ratio was generally sufficient to extract the incurred contaminants in the homogenized fish tissues. Conversely, extraction with a prototype vibration shaker often took 60 min to achieve 100% extraction efficiency. A main conclusion from this study is that accurate results for real samples can be obtained using batch extraction with a pulsed-vortexer in a simple and efficient method that achieves high sample throughput.