Kinetic spektrophotometric determination of 2,4-dichlorphenoxyacetic acid based on its inhibitory effect on the oxidation of sulfanilic acid by hydrogen peroxide

Abstract

A kinetic spectrophotometric method for measuring 2,4-dichlorphenoxyacetic acid (2,4-D) is described in this study. The proposed method is based on the inhibitory effect of 2,4-D on the oxidation of sulfanilic acid by hydrogen peroxide in the presence of Co(II) ion, which was monitored at 370 nm. The variables affecting the rate of the reaction were investigated and the optimum conditions were established. 2,4-D can be measured in the range of 0.07 -2.35 μg mL -1 and from 2.35 to 23.50 μg mL -1 with the detection limit of 0.004 μg mL -1 . This method was used to determined traces of 2,4-D in baby fruit juices. The HPLC method was used like a comparative method to verify the results. The results obtained by the proposed method were compared with those obtained by HPLC using UV -DAD detection and they showed a good agreement.