Multi-class, Multi-residue LC-MS/MS Method For Veterinary Drug Residues, Mycotoxins And Pesticide In Urine

Abstract

In this work, an liquid chromatography- tandem mass spectrometry (LC-MS/MS) methodology is proposed for the multi-class multi-residue screening of veterinary drugs, pesticides and mycotoxins in bovine urine, using an LS-MS/MS both in positive and negative mode.The method currently covers 72 analytes belonging to different families such as antibiotics, steroid hormones, β-agonists, lactones, thyreostatics and contaminants such as pesticides and mycotoxins. After comparing different sample preparation procedures, extraction with sodium acetate and phosphate buffer followed by enzymatic hydrolyze with β-glucuronidase and solid phase extraction with OASIS cartridges was selected as the most appropriate methodology. In the validation study were included linearity, limit of detection, limit of quantification, decision limit, detection capability, accuracy and precision of the method. The method was linear with R2>0.99. The limit of quantification were established between 0.19 μg/l and 16.7 μg/l, demonstrating the usefulnes of LC-MS/MS as an ideal tool for compliance monitoring in regulatory laboratories. The results for accuracy, expressed as recovery, were with values from 65 – 115%. Intra-day precision (repeatability) and inter-day precision (reproducibility) were expressed thought coefficient of variation. The CV was from 1.26 to 23.31 % for intra-day precision and from 2.29 to 29.42 % for inter-day precision. The results for accuracy and precision fulfill the criteria prescribed in the Commission Decision 2002/657/EC. The method was successfully applied for routine analysis of bovine urine samples. The routine analysis showed that the target components were not detected in the bovine urine samples.