Development and validation of multi-residue and multi-class method for antibacterial substances analysis in non-target feed by liquid chromatography – tandem mass spectrometry

ABSTRACT

A confirmatory HPLC-MS/MS method for the determination of residues of 11 antibacterial substances from different therapeutic class (β-lactams, lincosamides, fluoroquinolones, macrolides, pleuromutilins and sulfonamides) in animal feeds has been developed. The sample preparation is based on extraction with 0.1% formic acid in acetonitrile. Separation of the analytes was performed on biphenyl column with a gradient of 0.1% formic acid in acetonitrile and 0.1% formic acid in Milli-Q water. The developed method was validated following the guidelines included in the European Union Commission Decision 2002/657/EC. Limits of detection ranging from 79.22 to 193.60 µg/kg; instrumental and analytical linearity coefficients were above 0.99 for matrix-match calibration; and relative recoveries ranging from 76.04% to 117.39%. Repeatability of the method was in the range of 2.41–19.76% (CV, %), whereas reproducibility ranged from 6.52 to 28.40% (CV %). The method shown to be efficient and precise for quantification of the 11 antibacterial substances in animal feed. The results demonstrate the feasibility of the method for routine use to monitor these substances in feed. The validated method was successfully applied to eight suspect feed samples collected from the Association of American Feed Control Officials (AFFCO) and feed manufactures from Galicia (Spain) in June and July 2017. Of these 8 non-target feeds, 5 were positive for the presence of tiamulin, tylosin and sulfadiazine.

KEYWORDS:

• Non-target feed
• antibacterial substances
• LC-MS/MS
• residues
• 2002/657/EC

Conflict of interest

All authors declare that they have no conflict of interest. This manuscript has been read and approved by all of the authors, and it has not been submitted and is not under consideration for publication elsewhere.

Ethical approval

This article does not contain any studies with human participants or animals performed by any of the authors.

Additional information

Funding

This work was supported by the Xunta de Galicia and the European Regional Development Funds (FEDER), through grants [GI-1702 and GRC 2014/004] and KNOW (Leading National Research Centre) Scientific Consortium “Healthy Animal – Safe Food”, decision of Ministry of Science and Higher Education No. 05-1/KNOW2/2015.