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

Sensitive determination of 2,4-dichlorophenoxy acetic acid (2,4-D) 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-D was first converted to electroactive nitrated 2,4-D. 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 mu g L-1(3 x 10(-8) - 1.12 x 10(-6)M). The proposed method offered high sensitivity as well as good selectivity. A mechanistic study, showed four-electron reduction of nitrated 2,4-D to its hydroxylamine derivative. The proposed method was, also, applied to the determination of 2,4-D in environmental samples such as soil samples.