Development of electromembrane extraction using deep eutectic solvents for 22 representative veterinary drug residues...

The widespread occurrence of veterinary drug residues in animal-derived foods demands analytical methods that are not only sensitive and reliable, but also efficient and environmentally sustainable. To meet this need, this study developed a novel high-throughput platform based on 96-well electromembrane extraction (EME) using a designed deep eutectic solvent (DES) composed of 6-methylcoumarin and thymol (1:1, w/w) as a green and efficient supported liquid membrane. When coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS), the proposed DES-EME method enabled the simultaneous determination of 22 veterinary drugs in three kinds of complex food samples: honey, milk, and eggs. Under optimized conditions (10 mM trifluoroacetic acid, 50 V, 15 min), the method demonstrated excellent analytical performance, featuring wide linear ranges of 0.01-100 ng/mL with r ≥ 0.993, and limits of quantification (LOQs) expressed as original sample concentrations of 1.0 ng/g for honey and 25 ng/g for milk and eggs. Recoveries ranged from 40 to 99%, with relative standard deviations (RSDs) below 13% for most analytes. An AGREEprep score of 0.67 confirmed the greenness of the method, highlighting strengths in energy efficiency, sample throughput, and sustainability. Collectively, this work demonstrates that DES-EME represented a viable and sustainable approach for monitoring veterinary drug residues in complex food matrices.