Comparison of three cross-linking agents for imprinting diethylstilbestrol in solid-phase extraction

Molecularly imprinted polymer (MIP) has been heavily studied for years. However, most efforts focused on functional monomer and particular study of cross-linking agents on imprinting effect and pore structure is rare. In this paper, diethylstilbestrol (DES) imprinted polymers cross-linked by three types of agents and their imprinting effects in solid-phase extraction (SPE) were discussed. Evolution of UV spectral and simulation of cross-linking agents or monomer mixed with DES revealed that there was a particular interaction between divinylbenzene and DES. Clear imprinting effects towards DES showed for divinylbenzene made imprinted polymer (DM), with imprinting factors up to 16.02 (STD=2.20), while the other two imprinted polymers showed limited effects with imprinting factors of 4.95 (STD=0.45) and 1.63 (STD=0.54). Specific surface areas, pore volumes, and pore size distributions of the particles also confirmed that DM showed distinguished structure, and the average pore size of it was just fit the size of DES and bisphenol A (BPA), while no pore was found in divinylbenzene made blank polymer. Other imprinted and non-imprinted polymers showed no pore or big pores relatively. These results show that the cross-linking monomer is not merely an inert component for the MIPs, it could play a positive role in promoting interactions with the template to afford molecular recognition in imprinting DES. Copyright (C) 2011 John Wiley & Sons, Ltd.