Determination of the banned growth promoter moenomycin A in feed stuffs by liquid chromatography coupled to electrospray ion trap mass spectrometry.

Flavomycin complex is an antibiotic banned in the European Union as an additive in feed stuffs. As a consequence, the monitoring programmes for official control within the Community require analysis of feeds for possible illegal use of flavomycin. A method for unambiguous identification and quantification of moenomycin A, the main pharmacologically active component of flamomycin complex, in several feeds by liquid chromatography coupled to electrospray ion trap mass spectrometry (LC/ESI-MS/MS) is herein described for the first time. The method was developed to be used as a confirmative analytical tool for the network of Italian official control laboratories; both the singly and doubly charged molecular ions were observed as precursor ions, from which four product ions were selected for both quantitative analysis and unambiguous identification of moenomycin A. The method was in-house validated for feeds in the concentration range 0.50-30.0 microg/g, according to the Regulation 882/2004/EC requirements. Mean recoveries ranging between 83.9-94.2% and relative standard deviations <23% account for method trueness and repeatability, respectively. Moreover, other analytical performance parameters, i.e. method specificity, ruggedness, the linearity of detector response, the limit of quantification (LOQ), the limit of detection (LOD), and measurement uncertainty were evaluated and reported. The ion trap LC/ESI-MS/MS method is highly selective and reliable; high drug recovery, good reproducibility and an LOQ down to 0.10 microg/g guarantee its applicability for confirmatory purposes in the official control activity in Italy.