Preparation of a Pyrazosulfuron-Ethyl Imprinted Polymer with Hydrophilic External Layers by Reversible Addition-Fragmentation Chain Transfer Precipitation and Grafting Polymerization

Abstract

A new imprinted polymer with both functions of molecular recognition and macromolecule exclusion was synthesized for selective extraction of pyrazosulfuron-ethyl and removal of humic acids in environmental analysis. In the preparation, spherical pyrazosulfuron-ethyl imprinted polymers were synthesized by reversible addition–fragmentation chain transfer (RAFT) precipitation polymerization. The hydrophilic polymer layers were then grafted on the surface of the imprinted polymer microspheres using post-RAFT polymerization. The conditions that influence the selectivity, size, and uniformity of the imprinted microspheres were studied systematically. The computer simulation was employed to study the template-monomer interaction. The solubility parameters of poly(MAA-co-EDMA) and porogen were calculated to investigate the relationship between the particle size and the solubility parameter. The results indicated that the pyrazosulfuron-ethyl imprinted polymers have special affinity for the template and several structurally related sulfonylurea herbicides. The molecularly imprinted polymer (MIP) with external hydrophilic chains not only had function of template retention, but also better function of protein/humic acid exclusion. This research demonstrates that multifunctional imprinted material with a narrow size distribution can be prepared by the RAFT polymerization.