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-(α-methyl acrylate)-3-allylimidazolium bromide (1-MA-3AI-Br) as functional monomer, which can interact with SY through π-π, 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   μM   −   1.4   μM and 1.4   μM   −   16   μM with sensitivities of 5.0   μA/μM mm 2 and 1.4   μA/μM 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%.