Determination of chlorophenoxy acid herbicides and their esters in soil by capillary high performance liquid chromatography with ultraviolet detection, using large volume injection and temperature gradient Original Research Article

A simple method for the simultaneous determination of chlorophenoxy acid herbicides and their esters in soil is presented. Compounds studied are: 2,4-dichlorophenoxyacetic acid (2,4-D), 4-(2,4-dichlorophenoxy)butanoic acid (2,4-DB), 2,4-dichlorophenoxyacetic-1-butyl ester (2,4-D-1-butyl ester), and 2,4-dichlorophenoxyacetic-1-methyl ester (2,4-D-1-methyl ester). The chromatographic analysis was carried out by HPLC, after ultrasonic extraction, on a C18 packed capillary column with temperature gradient, large injection volumes and UV detection at 232 nm. Samples were spiked with amounts between 2.5 and 6.0 μg g−1 of each herbicide; recoveries obtained were between 72 and 97% (n=3 for each spiked level) and detection limits were between 0.3 and 0.5 μg g−1. Application of this procedure to the analysis of herbicides in ester and acid forms showed the effectiveness of the methodology proposed.