Grafting of molecularly imprinted polymers from the surface of silica gel particles via reversible addition-fragmentation chain transfer polymerization: A selective sorbent for theophylline

摘要

Molecularly imprinted polymers (MIPs) were grafted successfully from the surface of silica gel parti-cles via surface initiated reversible addition-fragmentation chain transfer (RAFT) polymerization usingRAFT agent functionalized silica gel as the chain transfer agent. The intrinsic characteristics of the con-trolled/living polymerization mechanism of RAFT allowed for the effective control of the grafting process.Thus the grafting copolymerization of methacrylic acid and divinyl benzene in the presence of templatetheophylline led to thin MIP film coating silica gel (MIP-Silica).The thickness of MIP film prepared in thisstudy is about 1.98nm, Which was calculated from the nitrogen sorption analysis results. Measured bind-ing kinetics for theophylline to the MIP-Silica and MIPs prepared by conventional bulk polymerizationdemonstrated that MIP-Silica had improved mass-transfer properties. In addition, the theophylline-imprinted MIP-Silica was used as the sorbent in solid-phase extraction to determine theophylline inblood serum with satisfactory recovery higher than 90%. Nonspecific adsorption of interfering com-pounds can be eliminated by a simple elution with acetonitrile, without sacrificing the selective bindingof theophylline.