Pesticide residue analysis is a critical part of any monitoring program to check MRL compliance in raw food commodities but also for residues in ingredients and finished foodstuffs. These analyses still present many challenges to testing laboratories, from sample processing, extraction and choices of cleanup and determination steps, through to data analysis, review, interpretation and reporting of results.
In this poster, we evaluate the performance of a large scope LC-MS/MS multiresidue method for the analysis of a number of samples, representative of the varieties types of commodity; high-water content (spinach), high acid and high-water content (strawberry), high oil and very low water content (soybean), high protein and low water and fat content (wheat) and difficult or unique commodities (black tea). Samples were extracted using QuEChERS CEN methodology, diluted and analyzed by LC-MS/MS. A targeted, time-windowed MRM method, containing 552 pesticides and relevant metabolites, was created from the Quanpedia database.
The performance of the LC-MS/MS method was assessed using the relevant guidelines from SANTE/12682/2019 focusing on pesticides in the current coordinated multiannual control programme of the EU. Blank extracts were spiked with a mixture of representative 256 pesticides at 0.005, 0.01 and 0.05 mg/kg. The method was found to yield excellent retention and peak shape for all analytes, even for early elutors using a post injector mixing kit. Despite the complexity of the various matrices, the LOD for the majority of the 256 compounds tested was 0.005 mg/kg; >90% for spinach, strawberry and soybean, 83% for tea and 79% for wheat.