Behaviour of triazine herbicides and their hydroxylated and dealkylated metabolites on a propazine-imprinted polymer -: Comparative study in organic and aqueous media

A molecularly imprinted polymer (MIP) obtained by precipitation polymerization with methacrylic acid as functional monomer and propazine as template was tested as a sorbent for the solid phase extraction of chloro- and methylthio-triazines and some of their dealkylated and hydroxylated metabolites. In order to confirm the interaction between the functional monomer and the template, H-1 NMR (CD2Cl2) analyses were made. It was observed that the hydrogen and/or nitrogen of the amino group of the propazine were involved in the formation of hydrogen bonds with the functional monomer. The possibilities offered by the propazine-MIP for the extraction of triazine and derivatives were studied in organic and aqueous media and different types of behaviour were observed. From organic medium, selective extractions of chloro- and methylthio-triazines were obtained after optimization of the extraction process, with recoveries higher than 75% in both cases. However, the hydroxylated metabolites were not retained on the propazine-MIP in organic medium. In aqueous medium, the chloro-triazines and the dealkylated chloro-metabolites were retained on the propazine-MIP by specific interactions, the recoveries obtained being a function of their polarity. Regarding the hydroxylated metabolites, these are retained on the propazine-MIP through non-specific hydrogen-bridge interactions. The methylthio-triazines undergo poor molecular recognition in this medium. 2005 Elsevier B.V. All rights reserved.