Determination of Traces of 2,4-Dichlorophenoxy Acetic Acid in Environmental Samples

Sensitive determination of 2,4-dichlorophenoxy acetic acid (2,4-0) was studied at a static mercury drop electrode in aqueous media and in the presence of Britton-Robinson buffer as the electrolyte. In this study, the electroinactive 2,4-0 was first converted to electroactive nitrated 2,4-0. Subsequent determination was carried out by differential pulse polarography. Under optimum conditions (pH = 11; v = 90 mV S^-1; modulation amplitude = 120 mV). the relative standard deviation was 4.5% and limit of detection in terms of nitrated 2,4-D was 5 (MU)g L^-1 (1.88 X 10-8 M) with linear concentration range from 8 to 300 /.1g L^-1(3 X 10^-8 -1.12 x 1O^-6M). The proposed method offered high sensitivity as well as good selectivity. A mechanistic study, showed fourelectron reduction of nitrated 2,4-0 to its hydroxylamine derivative. The proposed method was, also, applied to the determination of 2,4-0 in environmental samples such as soil samples.