A novel molecularly imprinted impedimetric sensor for melamine determination

A novel molecularly imprinted (MIP) impedimetric sensor was promoted for selective detecting melamine (MEL). The Au electrode modified with MIP poly (2-mercaptobenzimidazole) (PMBI) was prepared by electrochemical polymerization of 2-mercaptobenzimidazole (2-MBI) with cyclic voltammetry (CV) in the presence of template molecule MEL. The surface morphology and structure of MIP PMBI are characterized by atomic force microscopy (AFM), infrared spectra (IR), electrochemical impedance spectroscopy (EIS), and CV. The main driving force of recognition is the pi-donor-acceptor interaction between MEL and PMBI. The imprinted electrode could avoid the interference successfully. In addition, a linear response curve was obtained from 1.0 x 10(-8) M to 5.0 x 10(-5) M, with the detection limit of 3.0 x 10(-9) M. The sensor exhibits remarkable advantages, such as higher sensitivity, wider linear range and lower detection limit. The effective method has a potential application to monitor nonelectrochemically active substances in food analysis in the future. (C) 2012 Elsevier B.V. All rights reserved.