Simultaneous Determination of Residues of Non-Steroidal Anti-Inflammatory Drugs and Glucocorticosteroids in Animal Muscle by Liquid Chromatography-Tandem Mass Spectrometry

A method for the determination of a wide range residues of anti-inflammatory drugs (16 acidic non-steroidal anti-inflammatory drugs and four metamizole metabolites and five corticosteroids) has been was developed. In the first step of sample preparation, acetate buffer was added to minced muscle samples and 15-min ultrasound-assisted enzymatic hydrolysis was performed. Next, the samples were extracted twice with acetonitrile, freezed and analysed. The analytes were separated on a C18 column with a 25-min gradient of methanol/acetonitrile (8:2) and 0.05 M ammonium formate at pH 5.0 and determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The method was validated according to the requirements described in the Commission Decision 2002/657/EC: linearity, precision (repeatability and within-laboratory reproducibility), accuracy, decision limit CC alpha and detection capability CC beta were calculated. The method developed fulfilled the performance criteria and can be used in the official control of veterinary drug residues in food of animal origin. The method was positively verified in the proficiency test and in the analysis of incurred material.