Computational and Experimental Studies of Molecularly Imprinted Polymers for Organochlorine Pesticides Heptachlor and DDT

Molecularly imprinted polymers were synthesized to screen suitable functional monomers for the detection of organochlorine pesticides, heptachlor and DDT. Three functional monomers i.e., methacrylic acid (MAA), 4-vinyl pyridine (4VP) and styrene were investigated. Rebinding experiments show that while MAA is best for the detection of heptachlor, 4-vinyl pyridine suits well for DDT. The experimental findings are corroborated through density functional theory calculations. Molecular complexes of the monomer-pesticide were investigated for their binding energies. Computed binding energies agreed well with the experimentally obtained imprinting factors. The computed structures have been examined for the nature of interactions which stabilize the complex. Electrostatic interactions, studied through potential maps are able to explain the observed stabilization of the complexes.