پیام روز جهانی تئاتر

drop electrode in aqueous media and in the presence of Britton-Robinson bu er as the electrolyte. In this study, the electroinactive 2,4-D was rst converted to electroactive nitrated 2,4-D. Subsequent determination was carried out by di erential pulse polarography. Under optimum conditions (pH = 11;  = 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 g L􀀀1 (1:8810􀀀8 M) with linear concentration range from 8 to 300 g L􀀀1(310􀀀8 􀀀1:1210􀀀6M). The proposed method o ered high sensitivity as well as good selectivity. A mechanistic study, showed fourelectron 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.