Ionic liquids modified dummy molecularly imprinted microspheres as solid phase extraction materials for the determination of clenbuterol and clorprenaline in urine

New ionic liquid modified dummy molecularly imprinted microspheres (DMIMs) were synthesized by aqueous suspension polymerization using phenylephrine as dummy template and 1-allyl-3-ethylimidazolium bromide as co-functional monomer. The obtained DMIMs were characterized by Fourier transform infrared (FT-IR) and scanning electron microscopy (SEM), and empolyed as the special sorbent of solid-phase extraction for isolation of clenbuterol (CLB) and clorprenaline (CLP) from urine sample. The results indicated that the ionic liquid modified polymers were monodispersed microspheres and had high selectivity and adsorbability to CLB and CLP, and the matrix interferences could be efficiently eliminated from the samples. Meanwhile, the effect of template leakage of DMIMs on quantitative analysis was avoided. Compared with other commercial sorbents (HLB, PCX, C-18 and SCX), the DMIMs exhibited higher affinity and purification ability to CLP and CLB. Under the optimized conditions, good linearity was observed in a range of 0.90-400 mu g L-1 (r(2) = 0.9999) with LOD of 0.19 and 0.070 mu g L-1 for CLP and CLB, respectively. The recoveries at three spiked levels were ranged from 93.3% to 106% with RSD <= 5.6% (n = 3). (C) 2013 Elsevier B.V. All rights reserved.