Abstract: The use of square wave voltammetry (SWV) and square wave adsorptive stripping voltammetry (SWAdSV) in conjunction with a cyclic renewable silver amalgam film electrode for the determination of flumetralin is presented. Poor separation of two overlapped reduction peaks is significantly improved when hexadecyltrimethylammonium bromide is used as a component of the supporting electrolyte solution (together with BR buffer pH 9.5). The SW technique parameters were investigated and found optimal as follows: frequency 50 Hz, amplitude 40 mV, and step potential 5 mV. Accumulation time and potential were studied to select the optimal conditions in adsorptive voltammetry. The analytical curve was linear for the flumetralin concentration range from 1.0 × 10-6 to 1.0 × 10-5 mol dm-3 and from 5.0 × 10-9 to 1.0 × 10-7 mol dm-3 for SWV and SWAdSV, respectively. Detection limit of 6.5 × 10-10 mol dm-3 was calculated for accumulation time 60 s at -0.2 V. The repeatability of the method was determined at a flumetralin concentration level equal to 5.0 × 10-9 mol dm-3 and expressed as %RSD = 5.0% (n = 6). The proposed method was applied and validated successfully by studying the recovery of herbicide content in spiked environmental samples.
Keywords: Electrochemistry; Herbicides; Plant growth regulator; Silver amalgam film electrode; Square wave voltammetry.