UPLC-ESI-MS-MS Determination of Three β2-Agonists in Pork

Matrix-induced ion suppression and different polarity usually interfere with extraction, purification and drug analysis, therefore a method was developed for determination of three β2-agonists namely, salbutamol, ractopamine and clenbuterol in pork. After enzymatic hydrolysis, a 2.0 g homogenized pork sample was extracted, with perchloric acid–methanol (9:1, v/v) to precipitate protein, and then cleaned by mixed-mode Bond Elut Plexa PCX solid phase extraction (SPE) cartridges. Finally, the evaporated extract was reconstituted to 2 mL with initial mobile phase. The analytes were determinated by ultra performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (UPLC-ESI-MS-MS). Results indicate that the method is effective to reduce ion suppression phenomena. Recoveries of the three β2-agonists in most cases were better than 85% with relative standard deviations between 2 and 11%. The limits of detection (LOD) were 0.07–0.12 μg kg−1. The limits of quantitation (LOQ) ranged from 0.22–0.38 μg kg−1.