Determination of chlorophenoxy acid and dicamba herbicide residues by capillary reversed-phase liquid chromatography

Capillary liquid chromatography combined with solid phase extraction in a column packed with an anion exchanger based on MFE-Polymer (hydroxyethylmethacrylate, HEMA) containing quaternary ammonium functional groups, has been studied for multiresidual analysis of seven chlorophenoxy acid herbicides; 2,4-D, MCPA, 2,4-DP, 2,4-DB, MCPB, 2,4,5-TP, and the benzoic acid derivative Dicamba in green bean samples. The chromatographic analysis was carried out on a C-18 packed capillary column with gradient elution at 20 degrees C. The chlorophenoxy acid and Dicamba have been assayed in green bean samples spiked with amounts between 0.30 and 0.08 mg.kg(-1) for 2,4-D and MCPA, and between 0.15 and 0.04 mg.kg(-1) for all the other herbicides. The recoveries obtained were between 41 and 119% (n=4 for each spiked level).