Development and validation of a multi-residue LC-MS/MS analysis of non-steroidal anti-inflammatory drugs in milk and meat

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used substances in veterinary medicine for treating fever, pain and inflammation (e.g., coliform mastitis) in food-producing animals. Their widespread administration and occurrence in animal-derived products (meat and milk), impose a potential risk for humans. Maximum residue limits (MRLs) have been set for some (Commission Regulation 37/2010), implying the need for sensitive analytical methods to detect, identify and quantify possible residues.
This study aimed to develop and validate a multi-residue method for milk and meat to simultaneously detect, identify and quantify NSAIDs by liquid chromatography-tandem mass spectrometry (LC-MS/MS): carprofen, diclofenac, phenylbutazone, flufenamic acid, flunixin (or marker metabolite 5-hydroxy-flunixin in milk), ketoprofen, 4-methylaminoantipyrine (marker metabolite of metamizole in milk and meat), meloxicam and tolfenamic acid.
Mass spectrometric parameters and chromatographic conditions were optimized on a MicroMass Quattro Ultima triple quadrupole (Waters) and the Acquity UPLC (Waters) system, respectively. H2O/MeCN (95/5) + 0.1 % formic acid (solvent A) and MeCN + 0.1 % formic acid (solvent B) were used for chromatographic separation. Extraction was performed using MeCN. These methods were validated according to Commission Decision 2002/657/EC. Performance characteristics evaluated were specificity, linearity, recovery, repeatability, intra-laboratory reproducibility, decision limit and detection capability.