Unauthorised antibiotic treatments in beekeeping Development and validation of a method to quantify and confirm tylosin residues in honey using liquid chromatography-tandem mass spectrometric detection

A liquid chromatographic-tandem mass spectrometric (HPLC-MS/MS) method is proposed for the identification and quantification of tylosin in honey. Sample treatment involves an extraction in a Tris buffer at pH 10.5, followed by a solid-phase clean up step on an Oasis HLB column. Roxithromycin was used as the internal standard. Chromatographic separation of tylosin and roxithromycin was performed on an XTerra MS C-18 column (100 mm x 2.1 mm i.d., 5 mum) using a gradient of aqueous 0.01 M ammonium acetate pH 3.5 and acetonitrile as the mobile phase, at a flow rate of 0.25 ml min(-1). The method was validated according to the guidelines laid down by the Commission Decision 2002/657/EC. Tylosin residues were confirmed by MS/MS experiments considering the appropriate identification points. All validation parameters such as Ccalpha (lower than 3 ng g(-1)), Ccbeta (lower than 5 ng g(-1)), recovery and precision were assessed on the basis of the "critical ion" (less intense ion permitting unambiguous identification of the analyte). (C) 2004 Elsevier B.V. All rights reserved.