Confirmatory method for macrolide residues in bovine tissues by micro-liquid chromatography-tandem mass spectrometry.
A new confirmatory method for three macrolides (tylosin, tilmicosin and erythromycin) in bovine muscle, liver and kidney by micro-LC-MS-MS using an atmospheric pressure ionisation source and an ionspray interface has been developed. Roxithromycin was used as internal standard. The molecular related ions, [M+2H]2+, at m/z 435 for tilmicosin, and [M+H]+, at m/z 734 and 916 for erythromycin and tylosin, respectively, were the precursor ions for collision-induced-dissociation and two diagnostic product ions for each macrolide were identified for the unambiguous confirmation by selected reaction monitoring LC-MS-MS. Precision values (relative standard deviations) were all below 14.9%, whereas the overall accuracy (relative error) ranged from -17.7 to -9.8% for tylosin, from -17.5 to -10.7% for tilmicosin and from -19.6 to -13.7% for erythromycin, in all the investigated bovine tissues. The limits of quantification were 30 (muscle) or 40 (liver, kidney) microg kg(-1), 20 (muscle) or 150 (liver, kidney) microg kg(-1), 50 (muscle, liver) or 80 (kidney) microg kg(-1), 20 (muscle, liver) or 50 (kidney) microg kg(-1) for tylosin, tilmicosin, erytromycin and roxithromycin, respectively.
Draisci
R
R
Istituto Superiore di Sanità, Veterinary Medicine Laboratory, Rome, Italy. draisci@iss.it
Palleschi
L
L
Ferretti
E
E
Achene
L
L
Cecilia
A
A
D000818:Animals; D000900:Anti-Bacterial Agents / Q000032:analysis* / Q000493:pharmacokinetics; D001274:Atmospheric Pressure; D002138:Calibration; D002417:Cattle; D002853:Chromatography, Liquid / Q000379:methods*; D004350:Drug Residues / Q000032:analysis*; D004917:Erythromycin / Q000032:analysis / Q000493:pharmacokinetics; D007668:Kidney / Q000737:chemistry; D008099:Liver / Q000737:chemistry; D018942:Macrolides; D013058:Mass Spectrometry / Q000379:methods*; D018482:Muscle, Skeletal / Q000737:chemistry; D012015:Reference Standards; D014018:Tissue Distribution; D015645:Tylosin / Q000031:analogs & derivatives* / Q000032:analysis / Q000493:pharmacokinetics
D000900:Anti-Bacterial Agents; D018942:Macrolides; D004917:Erythromycin; C052319:tilmicosin; D015645:Tylosin