Determinação de resíduo de antibióticos β-lactâmicos e quinolonas em leite por cromatografia líquida acoplada à espectrometria de massas

Abstract

The presence of antibiotic residues in foods of animal origin has been considered a risk to public health in several countries around the world. Therefore, this work presents the development and validation of a rapid and selective method for the quantification of residues of β-lactam and quinolone antibiotics (Penicillin G, Oxacillin, Cloxacillin, Ceftiofur, Enrofloxacin and Ciprofloxacin, using Dicloxacillin and Sarafloxacin as internal standards) in raw bovine milk. A sample preparation consisted of only one protein precipitation step with a mixture of organic solvents acetone/acetonitrile 75:25 (v/v) assisted by ultrasonic bath, followed by centrifugation and injection into an Ultra-performance Liquid Chromatography system coupled with Electrospray Ionization Triple Quadrupole Mass Spectrometry (UPLC-ESI-QqQMS/MS). The separation occurred in 4,5 minutes using a reverse-phase Acquity UPLC BEH C18 column (1.7 µm, 50 mm x 2.1 mm), with the mobile phase consisting of water with 0.1% formic acid and acetonitrile. Multiple Reaction Monitoring (MRM) acquisition mode was employed in MS for high sensitivity and selectivity. The method was validated in accordance with the criteria established by Commission Implementing Regulation (EU) 2021/808, indicating recoveries from 76.3 to 98.9%, with coefficients of variation below 9% for both repeatability and intra-laboratory reproducibility, and trueness in the Maximum Residue Limit concentration level ranging from 96.9 to 108.7%. Linearity, selectivity, matrix effect, decision limit, robustness, detection limits, and quantification limits (LoQ) were also evaluated, achieving LoQ values as low as 0.1 x MRL. The method was successfully applied to eight real milk samples collected from tanks on commercial farms in the state of Minas Gerais.