Preparation of hydrophilic surface-imprinted ionic liquid polymer on multi-walled carbon nanotubes for the sensitive electrochemical determination of imidacloprid†
A hydrophilic ionic liquid monomer (i.e. 1-(α-methyl acrylate)-3-vinylimidazolium bromide) was immobilized on carboxylated multi-walled carbon nanotubes (MWNTs) by ion exchange, then reversible addition–fragmentation chain transfer precipitation polymerization (RAFTPP) was performed in the presence of a template, imidacloprid. The obtained imidacloprid imprinted material showed a netlike structure; it had a large surface and high adsorption capacity, and allowed rapid mass transfer. When it was supported on a 1-(3-aminopropyl)-3-methylimidazolium bromide functionalized-graphene (GR-IL) coated glassy carbon electrode, the resulting sensor presented a good electrochemical response to imidacloprid. After optimizing the preparation and determination conditions, a linear range of 0.2–24 μM with a sensitivity of 0.71 μA μM−1 mm−2 was obtained. The detection limit was 0.08 μM. The sensor also presented good selectivity and reproducibility. It was successfully applied to the determination of imidacloprid in practical samples and the recovery for the standards added was 94–107%.