Sensitive detection of β-agonists in pork tissue with novel molecularly imprinted polymer extraction followed liquid chromatography coupled tandem mass spectrometry detection.

A novel molecularly imprinted polymer micro-spheres (MIPMs) with phenylethanolamine A as the template and the p-vinylbenzoic acid as the functional monomer were synthesized for the selective absorption of clenbuterol and other β-agonists including brombuterol, bromchlorbuterol, clorprenaline and ractopamine. The absorption performances of the MIPMs were studied and the experimental results demonstrated that the extraction capacities of five β-agonists with MIPMs were about from 2.7 to 3.4 times as much as that with non-imprinted polymer micro-spheres. Based on the clean-up of five β-agonists in pork tissues with MIPMs, a sensitive determination method for five β-agonists coupled with ultra performance chromatography coupled tandem mass spectrometry detection has been developed. The limits of detection for five β-agonists were <0.02 μg/kg. The mean recoveries and repeatability of five β-agonists in pork tissues varied from 70.0% to 116.0% and from 2.5% to 10.4%, respectively. The developed method was successfully applied to analysis of 22 real pork tissues samples.