Determination of Fluorinated Pesticide Residues and Their Selected Transformation Products in High-Water-Content Foods Using Complementary LC–MS/MS and GC–MS/MS Methods

Fluorinated pesticides are an emerging class of environmental contaminants owing to their widespread agricultural use, high persistence, and ability to generate highly stable per- and polyfluoroalkyl substances (PFAS) during environmental degradation. Active ingredients containing fluorinated moieties undergo photolytic, hydrolytic, and microbial transformation, producing persistent metabolites such as trifluoroacetic acid (TFA), TFNA, TFNG, AMTT, and FM-6-1, which are highly mobile substances and may enter the food chain. To address this challenge, complementary LC–MS/MS and GC–MS/MS methods combined with QuEChERS and methanol extraction, and a modified QuPPe-based procedure for TFA and DFA were developed and validated for the determination of 76 fluorinated analytes, including fluorinated pesticides and selected transformation products with diverse physicochemical properties. Validation of the analytical workflow included the assessment of limits of quantification (LOQs), recovery, precision, expanded measurement uncertainty, and matrix effects at three spiking levels. LOQs ranged from 0.002 to 0.050 mg kg−1. Recoveries were 63.9–114.7% for GC–MS/MS and 40.3–109% for LC–MS/MS. The validated analytical workflow is suitable for monitoring fluorinated pesticides and selected transformation products in potatoes, onions, pears, watermelons, carrots, and cauliflower and may support routine food-safety control.