Molecular Imprinted Solid-Phase Extraction for Cleanup of Chlorinated Phenoxyacids From Aqueous Samples

Solid-phase extraction (SPE) represents a suitable way to clean up and preconcentrate samples containing traces of chlorinated phenoxyacids. High selectivity levels may be obtained using columns packed with materials based on well-defined molecular recognition mechanisms, such as immunoaffinity columns. SPE procedures involving molecular imprinted polymers (MISPE, molecular imprinted solid-phase extraction) have been proposed as a valid substitute for immunoaffinity procedures because of their simplicity of preparation and high stability to extreme chemical conditions. Here, we describe the preparation and the use of a polymer obtained by imprinting with the herbicide 2,4,5-trichlorophenoxyacetic acid as a molecular imprinted SPE sorbent. The polymer will be useful for extracting and concentrating selectively several strictly related phenoxyacids (2,4,5-trichlorophenoxyacetic acid; 2,4-dichlorophenoxyacetic acid; ( R,S )-2-(2,4,5- trichlorophenoxy)-propionic acid; ( R,S )-2-(2,4-dichlorophenoxy)-propionic acid; 2-methyl- 4-chlorophenoxyacetic acid; and ( R,S )-2-(2-methyl-4-chlorophenoxy)-propionic acid) from water samples before performing the analysis by capillary electrophoresis or high-performance liquid chromatography.