Preparation of Monolithic Imprinted Stationary Phase for Clenbuterol by In Situ Polymerization and Application in Biological Samples Pretreatment

A clenbuterol (CLB) molecule-imprinted monolithic stationary phase (MIMSP) with specific recognition for CLB and some other beta(2)-adrenergic receptor agonists was prepared by in situ polymerization technique utilizing methacrylic acid as a functional monomer, ethylene glycol dimethacrylate (EDMA) as a cross-linking reagent, and low polar solvents (toluene and dodecanol) as porogenic solvents. The optimal polymerization conditions were as follows: the molar ratio of template: monomer: initiator was 5:20:1, EDMA was 85% (v/v) in the total volume of monomer and EDMA, and toluene was 18% (v/v) in the total mixed porogen. The selectivity of the stationary phase for CLB and other beta(2)-adrenergic receptor agonists was evaluated by high performance liquid chromatography. Scatchard analysis was employed to explore the recognition mechanism. Then the CLB-MIMSP was used as a solid phase extraction (SPE) stationary phase for concentration and purification of CLB from pig liver samples. The results showed that the obtained CLB-MIMSP possessed high selectivity towards CLB and moderate selectivity towards some other beta(2)-adrenergic receptor agonists with characteristics of easy-made. The limit of detection was 10 ng g(-1), and recoveries of CLB were 99.16-113.06% with RSD 4.55-11.81% for the spiked pig liver samples. The CLB-MIMSP could be a promising SPE absorbent in CLB biological sample pretreatment.