Study and determinations of some sulfonylurea group pesticides by electrochemical techniques

In this study, voltammetric behaviors of triasulfuron, cyclosulfamuron and halosulfuron methyl have been investigated using dropping mercury electrode (DME), hanging mercury electrode (HMDE) and glassy carbon electrode (GCE). The analytical methods have been developed for the determination of these pesticides in supporting electrolyte, natural water and soil samples. The qualitative and quantitatlive determination of the analytes were performed by differential pulse polarography (DPP), square wave adsorptive stripping voltammetry (SWAdSV) and cyclic voltammetry (CV). Effects of accumulation potential, accumulation time, pulse amplitude, step potential and frequency were examined to determine optimum stripping conditions. Peak potentials of triasulfuron, cyclosulfamuron and halosulfuron methyl (vs. Ag/AgCl) were found as ?1031 mV, ?1348 mV and 1526 mV, respectively. Calibration plots were linear at the concentration range of 0.19?11.6 ?g mL-1 for triasulfuron with dropping mercury electrode by DPP, 10.0?350 ?g L-1 for cyclosulfamuron with hanging mercury electrode by SWAdSV and 4.10?50.0 ?g mL-1 for halosulfuron methyl with glassy carbon electrode by SWAdSV. The limit of detection (LOD) and limit of quantification (LOQ) were obtained 0.06 and 0.19 ?g mL-1 for triasulfuron, 3.50 and 10.0 ?g L-1 for cyclosulfamuron and 1.23 and 4.10 ?g mL-1 for halosulfuron methyl, respectively. In addition the interference of some inorganic species and pesticides have also been studied. The developed method was applied for the determination of the three pesticides spiked natural water and soil samples. The recovery values obtained in natural water samples are in the range of 98.4?103.0 %, 96.5?98.9 % and 103.8?106.7 % for triasulfuron, cyclosulfamuron and halosulfuron methyl, respectively. It was realized that the direct determination of triasulfuron and halosulfuron methyl in commercial herbicide formulations.