Validation of the QuEChERSER mega-method for the analysis of pesticides, veterinary drugs, and environmental contaminants in tilapia (Oreochromis Niloticus)

ABSTRACT

Diverse food safety programmes around the world are designed to help ensure production of safe food. To meet this need, the development and implementation of more efficient and effective analytical methods to monitor residues (pesticides and veterinary drugs) and contaminants in food is important. In this study, we report the validation results for a simple high-throughput mega-method for residual analysis of 213 pesticides and veterinary drugs, including 15 metabolites, plus 12 environmental contaminants (polychlorinated biphenyls) in tilapia muscle for implementation in routine laboratory analyses. The generic sample preparation method and analytical approach are known as QuEChERSER (more than QuEChERS). A small portion of the initial extract (204 µL) is taken for analysis by ultrahigh-performance liquid chromatography (UHPLC) tandem mass spectrometry (MS/MS) covering 145 analytes, and the remaining extract undergoes a salting out step followed by an automated robotic instrument top sample preparation (ITSP) cleanup, also known as micro-solid-phase extraction (µSPE), plus fast low-pressure gas chromatography LPGC-MS/MS for 134 analytes (66 pesticides are targeted in both UHPLC-MS/MS and LPGC-MS/MS). The mega-method was validated in spiked tilapia samples at 5, 10, 15, and 20 ng/g with 10 replicates per level over two days (n = 80 overall), and 70–140% recoveries with RSDs ≤20% were achieved for 92% of the analytes in LC and 82% in GC. No significant matrix effects were observed for the analytes in LPGC-MS/MS, and only 5% of the analytes exceeded ±20% matrix effect in UHPLC-MS/MS. Analysis of standard reference materials (NIST SRMs 1946 and 1947) for contaminants in freeze-dried fish showed acceptable results, further demonstrating that the QuEChERSER mega-method can be implemented to expand analytical scope and increase laboratory efficiency compared to the QuEChERS method.

Graphical abstract

KEYWORDS:

• UHPLC−MS/MS
• LPGC−MS/MS
• instrument top sample preparation (ITSP)
• µSPE
• tilapia
• pesticides
• veterinary drugs
• polychlorinated biphenyls (PCBs)
• QuEChERSER

Acknowledgments

The authors thank Tawana Simons, Robyn Moten, and Limei Yun for technical assistance in the lab.

Disclaimer

Mention of brand or firm name does not constitute an endorsement by the USDA above others of a similar nature not mentioned. The USDA is an equal opportunity employer.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed on the publisher’s website.

Additional information

Funding

The authors are grateful to the Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP, Project 2016/ 22370-2) and the Fulbright Visiting Scholar Program for the financial support received.