Electromembrane extraction of multi-class prohibited/restricted veterinary drugs from food samples – Exploring liquid membrane composition

Effective monitoring of veterinary drug residues in food is essential for legislation compliance and food safety, yet remains challenging due to low concentrations and complex matrices. This study introduced a miniaturized 96-well electromembrane extraction (EME) technique for pre-concentration and isolation 80 prohibited/restricted veterinary drugs from honey samples. Three liquid membranes were developed and characterized: V1 (“V” for veterinary), a mixture of 2-undecanone and 0.5 % 2-nitro-p-cymene, was optimal for extraction of quinolones, tetracyclines, and β-agonists. V2, a mixture of 2-nitrophenyl octyl ether and a deep eutectic solution (formed upon mixing 6-methylcoumarin with thymol in a 1:1 w/w ratio) in a 1:1 v/v ratio, with the addition of 0.5 % di(2-ethylhexyl) phosphate (DEHP), was suitable for macrolides and sulfonamides extraction. V3, a deep eutectic solvent formed upon 1-decanoic acid and camphor in a 1:1 w/w ratio with 1 % DEHP, was suitable for aminoglycosides and β-lactams. Operational parameters were fine-tuned to achieve optimal extraction efficiencies, with recoveries ranging from 20.1–117.5 %, 20.3–91.9 %, and 20.1–118.8 % for V1, V2, and V3, respectively. High precision was observed for compounds with recoveries over 40 % (intra-day: 0.4–27.7 %; inter-day: 2.6–33.0 %), and matrix effects were generally within 80–120 %. This work established a theoretical framework for EME in food analysis, highlighting its potential as a powerful sample pretreatment method for the detection of veterinary drug residues. The results demonstrated the feasibility and advantages of using EME for ensuring food safety and regulatory compliance.