This paper describes the development of an electroanalytical methodology using square wave voltametry (SWV) and hanging mercury drop electrode (HMDE) for determining the pesticide glyphosate in samples of natural waters. The electroactivity of glyphosate on the mercury electrode was obtained by complexation with Cu(II) were evaluated in the study the voltammetric parameters and experimental involved in the electrochemical reduction, such as: concentration of Cu(II), an effect of supporting

more »

... rolytes at different pH values and parameters of SWV. The best results were obtained in solution of NaNO 2 the 0,10 mol L -1 , pH 6,5, concentration of Cu(II) of 2,61 x 10 -7 mol L -1 , pre-concentration time of 120 sec, using the frequency of application of pulses of potential of 100 sec -1 , amplitude of pulses of potential of 50 mV and increase of sweep of 6 mV. The complex Cu(II)-glyphosate showed only a reduction peak at -0,1 V with quasi reversible process controlled by diffusion of the species on the electrode surface. Calibration curves were constructed and the detection limits (LD) and of quantification (LQ) obtained were (22,04 ± 0,42) µg L -1 and (73,46 ± 1,41) µg L -1 , respectively. The recovery tests showed values of (100,27 ± 1,96) % in pure water laboratory and (99,12 ± 2,14) % in real sample. Additionally, the methodology was applied for determination of glyfhosate in water sample collected in the creek from the Santa Clara, in the municipality of Candói/PR, with a value of (311,02 ± 23,72) μg L -1 glyphosate present in the sample. The percentage recovery in the investigated samples were above 99%, thus the gliphosate can be quantified in water samples by the proposed method.