Development, Validation and Application of Isotope Based Chromatographic/Spectrometric Techniques for Mixed Contaminants Including Some Veterinary Drug Residues in Bovine Meat

Abstract

The aim of this study was optimization of solid phase extraction method and optimization and validation of LC-MS/MS method for detection of β-agonists, antibiotics and organophosphorus pesticides using isotopically labeled internal standards in bovine meat. In the method were included total of 30 veterinary drugs from which 10 β-agonists, 15 antibiotics (cephalosporines, fluoroquinolones, β-lactams and sulfonamides) and 5 organophosphorus pesticides. Also in the method were included 12 isotopically labeled internal standards.The extraction of the residues from meat samples is with double extraction with acetonitrile:ethilacetate:acetic acid (49.5:49.5:1, v/v/v) and after first extraction, the solid phase extraction with Oasis HLB cartridges was used. For identification and quantification of the residue liquid chromatograph tandem mass spectrometer was used. With injections of standards of all veterinary drugs included in this study in MS/MS detector and ESI+ ionization the precursor and product ions were determined. After optimization of the chromatographic conditions (mobile phase, gradient) the method was validated. In the validation study were included following validation parameters: linearity, determination of CCα, CCβ, LOD and LOQ, accuracy and precision (interday and intraday reproducibility). From total of 30 veterinary drugs with this method were extracted 22. The results from linearity, accuracy and precision of the method for the extracted veterinary drugs were in accordance with criteria in the 2002/657/EC and the guidance for validation of analytical methods. The CCα, CCβ, LOD and LOQ were lower than recommended concentration of β-agonists and MRL values for antibiotics and pesticides. According of the results of the validation study, this method can be used in routine analysis of 22 residues in bovine meat.