High-throughput mega-method for the analysis of pesticides, veterinary drugs, and environmental contaminants in catfish by UHPLC-MS/MS and robotic mini-SPE cleanup + LPGC-MS/MS

Authors: NINGA, EDERINA - Agricultural University Of Tirana, Albania; Sapozhnikova, Yelena; Lehotay, Steven; Lightfield, Alan; MONTEIRO, SERGIO - Biological Institute, Brazil

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/22/2020
Publication Date: 5/22/2020
Citation: Ninga, E., Sapozhnikova, Y.V., Lehotay, S.J., Lightfield, A.R., Monteiro, S. 2020. High-throughput mega-method for the analysis of pesticides, veterinary drugs, and environmental contaminants in catfish by UHPLC-MS/MS and robotic mini-SPE cleanup + LPGC-MS/MS. Journal of Agricultural and Food Chemistry. https://doi.org/10.1021/acs.jafc.0c00995.
DOI: https://doi.org/10.1021/acs.jafc.0c00995

Interpretive Summary: Fast and efficient analytical methods with wide scope are needed to test food commodities for hundreds of diverse residues and contaminants. In this study, we merged together analysis of pesticides and environmental contaminants with analysis of veterinary drugs into one high throughput mega-method. This reduced the number of methods needed by half to cover the same analytical scope, thereby reducing time, labor, reagents, and other facets required for routine monitoring, and simultaneously increasing sample throughput. We developed and validated the mega-method for 349 contaminants in catfish at and below their regulatory levels. Out of 349 contaminants, 320 (92%) passed the validation criteria, demonstrating that the new method can be successfully used for the analysis of these contaminants in fish as part of regulatory monitoring programs for compliance and to protect human health.

Technical Abstract: The goal of this study was to develop and validate a new method for simultaneous determination of 106 veterinary drugs and 227 pesticides and their metabolites, plus 16 polychlorinated biphenyls (PCBs) at and below their regulatory levels established for catfish muscle in the European Union (EU) and USA. To do this, two different QuEChERS-based methods for veterinary drugs and pesticides and PCBs were merged into a single “mega-method.” The mega-method was validated in catfish at four different spiking levels with 10 replicates per level. Sample extraction of 2 g test portions was made with 10 mL 4/1 (v/v) acetonitrile/water, then an aliquot was taken for ultrahigh-performance liquid chromatography – tandem mass spectrometry (UHPLC-MS/MS) analysis of 106 veterinary drugs and 227 pesticides including metabolites. The remaining extract after salting out was subjected to automated mini-solid-phase extraction (mini-SPE) cleanup (Instrument Top Sample Preparation) for immediate injection in low-pressure gas chromatography (LPGC) – MS/MS. The cleanup was conducted in parallel with the 10 min LPGC-MS/MS analysis for 167 analytes, which was conducted in parallel with the 10 min UHPLC-MS/MS analysis for 231 analytes to increase sample throughput (49 analytes were included in both techniques). In MS/MS, three ion transitions were monitored for most targeted analytes to provide unambiguous identification as well as quantification. Satisfactory recoveries (70-120%) and RSDs =20% were achieved for 92% of the veterinary drugs and their metabolites, and for 91% of pesticides, metabolites and PCBs, demonstrating that the developed method is applicable for the analysis of these contaminants in fish as part of regulatory monitoring programs and other purposes.