Molecularly imprinted polymer for metsulfuron-methyl and its binding characteristics for sulfonylurea herbicides

A molecularly imprinted polymer (MIP) was prepared using metsulfuron-methyl (MSM) as the template molecule. A combinatorial protocol has been employed to optimize the polymer in terms of the kind and relative amounts of functional and cross-linking monomers. A copolymer of 2-(trifluoromethyl)acrylic acid (TFMAA) and divinylbenzene (DVB) showed the highest binding capacity for MSM. The binding characteristics of the imprinted polymers and MSM were evaluated in various solvents using equilibrium binding experiments. The results showed that the MIP binds MSM only in dichloromethane, which was used as the porogen during polymerization. Scatchard plot analysis revealed that two classes of binding sites were formed in the imprinted polymer with dissociation constants of 32.3μmoll^-1 and 1.7mmoll^-1, respectively. The specificity of the imprinted polymer was investigated by binding assays using MSM and other structurally related sulfonylurea herbicides. The results indicated that the imprinted polymer showed a marked selectivity for MSM.