Validation of the QuEChERSER method for 245 pesticides and environmental contaminants in barley and hemp by low-pressure GC: Comparison of triple quadrupole MS/MS and orbitrap HRMS for qualitative and quantitative analysis

Authors: MICHLIG, NICOLÁS - Oak Ridge Institute For Science And Education (ORISE); Lehotay, Steven

Submitted to: Journal of AOAC International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/4/2024
Publication Date: 11/20/2024
Citation: Michlig, N., Lehotay, S.J. 2024. Validation of the QuEChERSER method for 245 pesticides and environmental contaminants in barley and hemp by low-pressure GC: Comparison of triple quadrupole MS/MS and orbitrap HRMS for qualitative and quantitative analysis. Journal of AOAC International. https://doi.org/10.1093/jaoacint/qsae093.
DOI: https://doi.org/10.1093/jaoacint/qsae093

Interpretive Summary: Monitoring labs are a fundamental link in the food safety chain, and regulatory demands in a competitive economy call for analytical methods that are simpler, faster, more rugged, and broader in scope. The QuEChERSER mega-method provide acceptable analytical results for a wide range of different types of foods and contaminants in a high-throughput procedure. This consolidation of applications and methods serves to save a great deal of time, labor, waste, space, and cost. In this study, the QuEChERSER method was validated for 245 pesticides and other chemical residues in barley and hemp matrices, including a comparison of performance results using two different mass spectrometry detection techniques. Both detectors generally met method acceptability requirements using the mega-method, and each had technical advantages over the other. In the future, many labs worldwide are expected to adopt the QuEChERSER method to reduce expenses compared to current operations.

Technical Abstract: Background: Monitoring labs are a fundamental link in the food safety chain, and regulatory demands in a competitive economy call for analytical methods that are simpler, faster, more rugged, and broader in scope. The QuEChERSER mega-method introduced in 2021 meets these monitoring needs, which includes high sample throughput, automated cleanup of extracts, and fast low-pressure gas chromatography (LPGC). Objective: The goal of this work was to extend the QuEChERSER method to additional matrices and more analytes using LPGC, including comparison of the analytical performances of two different mass spectrometric (MS) analyzers: triple quadrupole tandem MS/MS and orbital ion trap (orbitrap) high-resolution (HR)MS. Methods: The QuEChERSER mega-method was validated for 245 pesticides and environmental contaminants in barley grains and hemp pellets using automated instrument top sample preparation (ITSP) coupled with LPGC-MS/MS or LPGC-HRMS (orbitrap). Results: Targeted MS/MS detection proved to be more sensitive than orbitrap using full data acquisition, leading to lower limits of quantification (LOQs) with more analytes yielding acceptable recoveries (70-120%) and repeatabilities (RSDs <20%). In barley, 89% of the compounds met validation criteria in MS/MS and 74% in HRMS, which in hemp were 81% and 66%, respectively. Qualitatively, orbitrap HRMS yielded 1% false positives compared to 3-4% in MS/MS, but due to the higher LOQs, the rates of false negatives were 14-17% in orbitrap vs. 6-10% in MS/MS for the different matrices. Conclusion: The QuEChERSER mega-method including ITSP+LPGC coupled with MS/MS or orbitrap analysis is a robust approach for multiple applications. In the comparison, MS/MS outperformed the orbitrap in terms of sensitivity, but the orbitrap advantages of easier method development, greater selectivity, and possibility for nontargeted/retrospective analysis permit even broader expansion of analytical scope in the future.