Electrochemical Preparation of a MIP-Glassy Carbon Electrode for the Determination of Dimethoate

In this work a dimethoate-polypyrrole (dim-PPy) MIP films were electropolymerized by cyclic voltammetry (CV) on the surface of glassy carbon electrode (GCE), using pyrrole (Py) as the monomer and dimethoate (dim) as the template. Dimethoate is electro-inactive, therefore an electroactive K₃[Fe(CN)₆] solution was used as probe in the CV and square wave voltammetry (SWV) for the evaluation of the performance of the imprinted (MIP) and non-imprinted (NIP) films. To investigate the analytical performance of the MIP system in the dimethoate detection, the dim-free MIP films electrode, obtained after the removal of the dimethoate, was placed in solutions containing dimethoate at different concentrations for the analyte rebinding. After the rebinding step, for the MIP films there was a decrease of the response and the current was lower than that for the dim-free MIP films. The decrease of the response could thus be used to indirectly detect the analyte quantitatively. For the NIP films, the response of K₃[Fe(CN)₆] was very small and showed no obvious difference with different dimethoate concentrations in the rebinding step. These results illustrated that the dim-PPy MIP film system is simple to construct and easy to operate and could be used to recognize dimethoate.