Sensitive Assay of Clenbuterol Residues in Beef by Ultra-High Performance Liquid Chromatography Coupled with Mass Spectrometry (UPLC-MS/MS) and Solid-Phase Extraction

The use of clenbuterol (CLE) as a growth-promoting agent in livestock is banned in the USA, European Union, and Mexico. Nevertheless, different studies have reported the presence of this agent in meat products, potentially causing intoxication in consumers. In this study, ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) is proposed for CLE determination in beef. A simple solid-phase extraction step was used as a cleanup sample method; the chromatographic separation was achieved with anAcquity UPLC HSS T3 column using a mobile-phase formic acid and methanol. We use a XEVO-TQS detector by positive-ion electrospray in the multiple reactions monitoring modes. The mass transitions monitored were m/z 277.08 -> 202.95 for CLE and m/z 286.1 -> 203.9 for clenbuterol-D9, used as an internal standard. The method was linear over the concentration range of 0.1-1.6 ng/g. Once validated, the method was applied to monitor CLE in beef samples collected at local markets of San Luis Potosi (central region of Mexico). Despite the ban on the use of CLE to grow cattle, we find levels of beta-agonist, with concentrations between 0.6 and 10.4 ng/g. Our method is ideal for routine analysis for quality control and food safety.