Molecularly imprinted label-free sensor platform for impedimetric detection of 3-monochloropropane-1,2˗diol

Abstract

The fabrication of a molecularly imprinted overoxidized polypyrrole MIP(oPPy) on graphene oxide (GO) modified single-use pencil graphite electrode (PGE) for the quantitative analysis of 3˗monochloropropane˗1,2˗diol (3˗MCPD), an important food processing contaminant, was reported for the first time. In situ electropolymerization of oPPy in the presence of template molecules (3˗MCPD) onto GO/PGE was carried out via cyclic voltammetry method in a pH-controlled solution. To evaluate the most appropriate sensor response, various experimental conditions (such as film thickness, analyte/monomer ratio, desorption/adsorption time etc.) were discussed and optimized. The re-adsorption of 3-MCPD was screened by electrochemical impedance spectroscopy (EIS) on imprinted cavities capable of 3-dimensional recognition of the target molecule. The electrochemistry of a redox probe (ferrocyanide/ferricyanide) was utilized for the impedimetric detection of 3-MCPD with a dynamic linear range of 2−500 nM and low sensing limit as 1.82 nM. The combination of GO and oPPy to construct a MIP platform provided a superior recognition performance for 3-MCPD in a label-free, disposable and cost-effective way. In order to demonstrate the practical applicability, standard addition method was employed in soy sauce samples. The achieved high recovery rates displayed that MIP(oPPy)-GO/PGE hold significant promise for future on-site studies in real food matrices for food safety control purposes.