Herbicide Assay Using an Imprinted Polymer-Based System Analogous to Competitive Fluoroimmunoassays

A fluorescent ligand displacement assay has been developed for the herbicide 2,4-dichlorophenoxyacetic acid based on a molecularly imprinted polymer. The format of the assay is analogous to competitive fluoroimmunoassay formats and uses a coumarin derivative as a nonrelated fluorescent probe. This avoids the use of radiolabels commonly employed in imprinted polymer-based assays and, thus, the handling of radioactive material. Specificity and sensitivity of the assay are on a par with a radioligand displacement assay using the same molecularly imprinted polymer and radiolabeled 2,4-dichlorophenoxyacetic acid. The assay can be used both in aqueous buffer and in organic solvents, the detection limit being about 100 nM.