This study presents a method for analyzing nine highly polar contaminants in infant formulas, combining ultrasound, low temperature, and dispersive solid-phase extraction, followed by LC-MS/MS. Validation according to SANTE 11312/2021 v2 guidelines were performed showing good linearity (R² = 0.99), precision (RSD ≤20 %), and appropriate limits of quantification (10-30 μg/kg). Recoveries ranged from 70 % to 103.1 % except for perchlorate (54.4 % at 250 μg/kg) and glufosinate (63.7 % at 150 μg/kg). The method was applied to 30 liquid and powder samples based on soy, rice, cow, and goat milk, and phosphonic acid, chlorate, perchlorate, fosetyl-Al, and glufosinate were detected in 33 % of the samples. Perchlorate showed the highest concentration (139.88 μg/kg), with intake values exceeding the EFSA limit (0.00003 mg/kg body weight/day). For other compounds, daily intakes were within legal limits. An untargeted analysis using LC-Q-Orbitrap-MS/MS tentatively identified 39 additional compounds.

The complexity of the milk matrix, driven by its lipid-rich composition, complicates pesticide residue analysis. This study developed a simplified and robust analytical procedure for the quantification of 250 pesticides in cow’s milk. Sample preparation involved acidified ethyl acetate extraction followed by centrifugation at 0 °C. A subsequent clean-up step was performed using micro solid-phase extraction (μSPE) in a 96-well format with the enhanced matrix removal-lipid (EMR-lipid) sorbent. Final extracts were analyzed by gas chromatography coupled to high-resolution mass spectrometry (GC-Q-Orbitrap-MS). Method validation demonstrated satisfactory linearity within the 5–100 µg/L range, recoveries between 70.6% and 119.8%, and precision, expressed as relative standard deviation (RSD), was acceptable for both intraday (1.8–19.2%) and interday (1.6–18.5%) conditions. The limit of quantification (LOQ) was set at 10 µg/kg for all compounds. The method was applied to 23 commercial cow’s milk samples, and no pesticide residues were detected above the current European Union (EU) maximum residue limits (MRLs).