Mass spectrometric approaches to the confirmation of maduramicin alpha in chicken fat

Because of the structural information it provides, mass spectrometry has gained widespread acceptance as the preferred analytical technique for drug residue confirmatory procedures. For the confirmation of the polyether ionophore antibiotic, maduramicin alpha, in chicken fat, the techniques of desorption chemical ionization (DCI), thermospray liquid chromatography/mass spectrometry (TSP LC/MS), and thermospray liquid chromatography/tandem mass spectrometry (TSP LC/MS/MS) were investigated as potential approaches. Sample clean-up was found to be totally inadequate for DCI and only marginally acceptable for TSP LC/MS. Only TSP LC/MS/MS adequately resolved the analyte from the tissue coextractives and generated satisfactorily reproducible mass spectrometric data for a confirmatory method. The techniques developed here should be applicable to other commonly used polyether ionophores.