Abstract: A simple and efficient method based on a novel solid phase extraction (SPE) cartridge and ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed for the determination of clenbuterol residue in pork. The minced pork sample was ultrasonically extracted by 5% (v/v) perchloric acid and centrifuged at 10000 r/min for 15 min, then the supernatant was purified by an SMCX cartridge, which is a novel SPE column based on homemade silica matrix with two mixed modes of reversed-phase and strong cation exchange, for the selective enrichment and purification of the analyte. The linear range of the method was 0.25~50 μg/kg with a correlation coefficient of 0.9982. The average recoveries ranged from 62.2% to 72.0% at the three spiked levels of 1.25, 12.5 and 50 μg/kg with the relative standard deviations (RSDs) between 4.2% and 6.1%. The limit of detection (S/N=3) was 0.05 μg/kg. The method is simple, fast and can be extended to enrich and determine β-agonist drugs.

Key words: clenbuterol, pork, SMCX cartridge, ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), solid phase extraction (SPE)