Assessment of a specific sample cleanup for the multiresidue determination of veterinary drugs and pesticides in salmon using liquid chromatography/tandem mass spectrometry

Abstract A novel sample treatment approach based on a modified QuEChERS method was evaluated for the simultaneous determination of veterinary drug and pesticide residues in salmon in this work. To improve the QuEChERS performance, Enhanced Matrix Removal-Lipid dSPE cleanup sorbent was evaluated for the first time for the simultaneous analysis of these organic contaminants in salmon samples. Due to this sorbent can effectively remove coextracted families of lipids. To cover a wide range of polarities, 65 pesticides and 41 veterinary drugs with log Kow ranging from −1.4 to 5.5 were selected. Extracts after cleanup were analyzed by ultra-high-performance liquid chromatography-tandem mass spectrometry for analyte confirmation and quantitation. Outstanding results were obtained for both extraction efficiency and matrix removal. A negligible matrix effect was obtained for 57% of the studied compounds, whereas the rest presented a soft matrix effect. The recovery for spiked samples was in agreement with the current European Union recommendations for most compounds. The rest of the parameters were also satisfactory, reaching quantification limits lower than 3.7 μg kg−1 in all cases. The precision was better than 20% in all cases. Finally, the method performance was successfully demonstrated with 20 salmon samples, five of which contained pesticide or veterinary drug residues.