Determination of clenbuterol from pork samples using surface molecularly imprinted polymers as the selective sorbents for microextraction in packed syringe

In this study, a selective sample pretreatment procedure combing surface molecularly imprinted polymers and microextraction in packed syringe (SMIPs-MEPS) was developed for the analysis of clenbuterol (CLB) from pork samples. SMIPs for CLB were synthesized on silica gel particles through a sal-gel process. A series of characterization and adsorption experiments revealed that the SMIPs exhibited porous structures, good thermal stability, high adsorption capacity and a fast mass transfer rate. The obtained SMIPs were employed as selective sorbents of SMIPs-MEPS for extraction of CLB from pork samples. Several parameters affecting the extraction efficiency were investigated, including the pH of sample solution, number of draw-eject cycles, volume of sample, type and volume of washing solution, and the type and volume of elution solution. Under the optimized conditions, a simple and rapid method for the determination of CLB from pork samples was established by coupling with high performance liquid chromatography (HPLC). The whole pretreatment process was rapid and it can be accomplished with 2 min. The limit of quantitation and the limit of detection for CLB were 0.02 and 0.009 mu g kg(-1), respectively. The average recoveries of CLB at three spiked levels ranged from 86.5% to 91.2% with the relative standard deviations (RSD) <= 6.3%. (C) 2013 Elsevier B.V. All rights reserved.