Analysis of beta-agonist residues in bovine hair: Development of a UPLC-MS/MS method and stability study

Beta-sympathomimetic compounds are widely used in therapy because of the bronchodilator, smooth muscle-relaxant and tocolytic properties. However, their growth promoting and performance enhancing effects are often subject to illegal use. The present work describes the development of a fast and reliable analytical multiresidue method for the confirmation 20 β-agonist compounds in animal hair. The procedure is based on alkaline digestion, LLE with organic solvents, SPE clean up and liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis, and is suitable for the public Official control of β-agonist residues in hair sample. Validation was performed according to Commission Decision 2002/657/EC requirements. Independent samples spiked with the investigated compounds in the range 0.2-10.0microgkg^-1 are showing intra-day and inter-day precision (RSD) lower than 17.8% and 19.7%, respectively. Linearity, measured in the range of 0.1-10.0microgkg^-1, resulted with a Pearson's r>0.996. The decision limits (CCα) for the all investigated beta agonists resulted in the range 0.2-1.0microgkg^-1. Furthermore, the method was tested on real hair samples obtained from cattle, known as positive to clenbuterol, in order to check its effectiveness and the β-agonists stability.