Application of LC-MS/MS for the analysis of highly polar contaminants in infant formulas: occurrence, exposure assessment, and unknown analysis

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.