Preparation and application of sunset yellow imprinted ionic liquid polymer - ionic liquid functionalized graphene composite film coated glassy carbon electrodes

A novel water-compatible molecularly imprinted ionic liquid polymer - ionic liquid functionalized graphene composite film coated glassy carbon electrode (MIP - rGO-IL/GCE) is presented. It is fabricated by coating a GCE with amine-terminated ionic liquid functionalized graphene (rGO-IL) and then with water-compatible MIP suspension. The water-compatible MIP is prepared by free radical polymerization in methanol-water system using sunset yellow (SY) as template and ionic liquid 1-(alpha-methyl acrylate)-3-allylimidazolium bromide (1-MA-3AI-Br) as functional monomer, which can interact with SY through pi-pi, hydrogen-bonding and electrostatic interaction. The resulting MIP - rGO-IL/GCE shows good performance when it is used for the differential pulse voltammetric determination of SY. Under the optimized conditions (i.e. pH 7.5, 0.1 M phosphate buffer, preconcentration under open-circuit for 570 s), the peak current is linear to SY concentration in the ranges of 0.010 mu M - 1.4 mu M and 1.4 p mu M - 16 mu M with sensitivities of 5.01 mu A/mu M mm(2) and 1.4 mu A/mu M mm(2) respectively; the detection limit is 4 nM (S/N = 3). The electrode has been successfully applied to the determination of SY in some soft drinks, and the recoveries for the standards added are 95% - 107%. (C) 2013 Elsevier Ltd. All rights reserved.