Sensitively Voltammetric Determination of Vanillin with a Molecularly Imprinted Ionic Liquid Polymer-Carboxyl Single-Walled Carbon Nanotubes Composite Electrode

A molecularly imprinted ionic liquid polymer-carboxyl single-walled carbon nanotubes composite coated glassy carbon electrode (MIP-SWNTs-COOH/GCE) was prepared. The MIP was synthesized by using vanillin (VA) as template, hydrophilic ionic liquid 1-(alpha-methylacrylate)-3-allylimidazolium bromide as functional monomer and ethyleneglycol dimethacrylate as crosslinker. The MIP was water-compatible and had porous structure and large surface. The ionic liquid and VA could interact through pi-pi and hydrogen bonds, thus the imprinted sites possessed good specific recognization ability. When it was loaded on SWNTs-COOH film, the resulting electrode exhibited highly selective and sensitive response to VA in aqueous solution. After optimizing the conditions, linear response ranges of 0.4-8 and 10-140 mu M with sensitivities of 178 mu A/mu M cm(2) and 8.1 mu A/mu M cm(2) were obtained. The electrode was successfully applied to the detection of VA in biscuit, soybean milk powder and vanilla tea, and the recoveries for standards added were 94-107%.