Validation of a method for the analysis of quinolones residues in bovine muscle by liquid chromatography with electrospray ionisation tandem mass spectrometry detection

A liquid chromatography-tandem mass spectrometry method for the determination and confirmation of nine quinolones was optimised and validated according to Commission Decision 2002/657/EC. Analytes were extracted from veal muscle with water and extracts purified with 96-well plates Oasis HLB cartridges. Separation was carried out in a silica-based C₁₈ column (50 mm × 2.1 mm) with mobile phases consisting of water/acetonitrile mixtures containing acetic acid. Linear calibration curves in the ranges 4-400 and 50-800 ng g⁻¹, with correlation coefficients at least 0.995, were obtained for all the analytes. At concentration levels above 10 ng g⁻¹, quantification errors were lower than 10% and repeatability and within-laboratory reproducibility standard deviations below 6% and 10%, respectively. Decision limits and detection capabilities are reported.