Simultaneous determination of multi-class veterinary drug residues in different muscle tissues by modified QuEChERS combined with HPLC-MS/MS

A novel method for the determination of 55 multi-class veterinary drug residues in different muscle tissues (porcine, bovine and ovine animals) by modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) combined with high performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (HPLC-MS/MS) is described. The veterinary drugs focused on here belong to several families, such as macrolides, quinolones, sulfonamides, benzimidazoles, and β-agonists (unbound). The samples were first extracted with 5% acetic acid in acetonitrile, followed by cleanup with QuEChERS and sequential analysis by HPLC-MS/MS technique. It was found that the majority of analytes (89.1%) can achieve the mean recoveries between 70% and 120% in the examined matrices. The repeatability and reproducibility are lower than 20% for 94.1% and 90.3% of total analytes in these matrices, respectively. 86.7% of the compounds could have γ2 of 0.99 or above. The range of limits of quantification (LOQ) for these compounds in porcine, bovine and ovine is 0.1 to 18.4 μg kg−1, 0.1 to 20.0 μg kg−1, and 0.1 to 18.4 μg kg−1, respectively. Finally, the method was applied to real samples, and ofloxacin was found in one bovine sample at 2.5 μg kg−1. The method is sensitive, accurate, quick and simple, and suitable for the routine analysis of meat products.