One-shot quantification of 313 PPCPs and pesticides in bovine milk by modified-QuEChERS-UHPLC-MS/MS

A high-throughput method based on modified QuEChERS and ultra-high performance liquid chromatography-tandem mass spectrometry was developed for the simultaneous determination of 313 pharmaceuticals and personal care products (PPCPs) and pesticides in bovine milk. The sample preparation procedure was strategically optimized, selecting 2% acetic acid in acetonitrile as the extraction solvent and diatomaceous earth as the sole clean-up sorbent. The method demonstrated excellent sensitivity, with limits of detection and quantification ranging from 0.5 to 500 ng/kg and 1 to 1000 ng/kg, respectively. The mean recoveries ranged from 70.1% to 110.8%, with intra-day and inter-day relative standard deviations below 15% for the vast majority of compounds. The practical applicability of the proposed method was confirmed by analyzing commercial milk samples, revealing the presence of 37 residues, including certain prohibited substances. This method presents a robust, efficient, and reliable tool for the large-scale monitoring of multi-class contaminants in milk.