Isoproturon-imprinted polypyrrole films were electrochemically synthesized onto glassy carbon (GC) electrodes in an ethanol/aqueous solution of pyrrole as a monomer, isoproturon as a template molecule and LiClO4 as supporting electrolyte. Electropolymerization was performed by cyclic voltammetry and chronoamperometry. The isoproturon template molecules were successfully trapped in the polypyrrole film where they created artificial recognition cavities. After the electrochemical extraction of the template, the polypyrrole film acted as a molecularly imprinted polymer (MIP) for the selective recognition of isoproturon whereas the non-imprinted polymer (NIP) film, made in the same conditions except for the presence of isoproturon, did not exhibit any interaction. The MIP and NIP films were characterized by cyclic voltammetry in the presence of redox probes and the thickness of the polymer layers was estimated by EQCM (Electrochemical Quartz Crystal Microbalance) and calculated using Faraday's law. The isoproturon-imprinted polypyrrole films were found to selectively detect isoproturon even in the presence of the interferents carbendazim and carbamazepine. Its limit of detection (LOD) in milli Q water, achieved via square wave voltammetry was as low as 0.5 μg L-1, whereas in real water samples it was found to be 2.2 μg L-1.
Keywords: Electrochemical sensors; Isoproturon detection; Molecularly imprinted polymers; Polypyrrole films.
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