Determination of non-steroidal anti-inflammatory drugs in milk by liquid chromatography-tandem mass spectrometry (LC-MS/MS)

Abstract

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used in human and veterinary medicine because of their main properties: anti-inflammatory, analgesic and antipyretic. The use of these drugs has increased significantly over the world in the last decades. The widespread use of NSAIDs can cause serious side effects such as gastric and intestinal disturbances. The control of the presence of residues of NSAIDs in food of animal origin is mandatory following Europe legislation; for this reason analytical methods for milk and meat analysis have to be set up. In this work, a method based on the Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) approach was developed for the determination of NSAIDs in milk samples by liquid chromatography-tandem mass spectrometry (LC-MS/MS) with electrospray ionization (ESI) using the Multiple Reaction Monitoring (MRM) mode. A new sample preparation method was developed, using 5% acetic acid in acetonitrile as extraction system and with a clean-up step by dispersive solid phase extraction (d-SPE) using sorbent C18. Mass spectrometric parameters and chromatographic separation were optimized. Two MRM transitions were monitored for each analyte in positive or negative electrospray mode.