Qualitative screening of 116 veterinary drugs in feed by liquid chromatography–high resolution mass spectrometry: Potential application to quantitative analysis

Veterinarian and human pharmaceuticals may be intentionally added to animal feed to enhance animal production. Monitoring these substances is necessary for protecting the consumers. In this work, a screening method covering 116 human and veterinary drugs has been developed and validated in five types of animal feed at 0.02 and 0.2 mg kg−1. After a simple extraction and dilution, the samples were analysed by ultra-high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UHPLC-QTOF MS). Nearly all compounds tested were detected at 0.02 mg kg−1, based on the presence of the accurate-mass (de)protonated molecule. However, the identification using a second accurate-mass ion was more problematic at this level. Finally, the procedure was applied to 22 feed samples, where trimethoprim, robenidine, or α- and β-nandrolone were detected and identified. The potential applicability of the method to quantitative analysis of the compounds detected in the samples was also evaluated.