Double-imprinted potentiometric sensors based on ligand exchange for the determination of dimethoate

This paper describes a dimethoate imprinted polymeric potentiometric sensor for the determination of dimethoate that was designed by dispersing the dimethoate-imprinted polymer in dibutyl phthalate plasticizer and then embedded in polyvinyl chloride matrix. The method is based on molecularly imprinted polymer (MIP), which can be synthesized by using dimethoate as a template molecule, chitosan-Cd(II), and 3-mercaptopropyl-trimethoxysilane as a functional monomer and TEOS, and ephychlorohydrin as a cross-linking agent. We have studied a method for the selective binding behavior of dimethoate compounds on the surface of imprinted polymers which is prepared using ligand-exchange (LE) (chitosan-Cd(II)) monomer. The MIP-LE-1 and MIP-LE-2 based membranes have shown a detection limit of 4.3x10(-6) mmolL(-1) and 3.5.10(-5) mmolL(-1), respectively. The sensor has exhibited a response time of 35min for MIP-LE-1 and 120min for MIP-LE-2. They are stable for more than three months.