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

BACKGROUND: Monitoring laboratories 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 "quick, easy, cheap, effective, rugged, safe, efficient, and robust" (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 matrixes and more analytes using LPGC, including comparison of the analytical performances of two different mass spectrometric analyzers: triple quadrupole tandem mass spectrometry (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 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 versus 6-10% in MS/MS for the different matrixes. 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 the possibility for non-targeted/retrospective analysis permit even broader expansion of analytical scope in the future. HIGHLIGHTS: ITSP+LPGC-MS/MS or -HRMS (orbitrap) analysis as part of the QuEChERSER mega-method is a useful and efficient way to monitor for contaminants in foods.