Characterization and use of copper solid amalgam electrode for electroanalytical determination of triazines-based herbicides

This paper reports the construction, characterization and use of copper solid amalgam electrode in the study of the electrochemical behavior of atrazine and ametryne herbicides by square-wave voltammetry. This study was used as basis for the development of sensitive analytical methods for the determination of these herbicides in natural water, avoiding the use of mercury, by means of a solid electrode that presents high sensitivity and minimizes any environment contamination with mercury residues. The experimental and voltammetric conditions were evaluated and the results showed a reduction peak for atrazine at - 0.98 and at - 1.1 V vs. Ag/AgCl 3.0 mol L-1 for ametryne, both with characteristic of all irreversible electrode reaction in an electrochemical diffusion controlled process, involving two electrons for each herbicide reduction. Based oil voltammetric Studies, it has been demonstrated that the most possible mechanism for the reduction of herbicides involved reduction of bond carbon-chloride for atrazine and the reduction of bond carbon-SCH3 for ametryne. The detection limit of herbicides obtained in pure water (laboratory samples) was shown to be lower than the maximum limit of residue established for natural water by the Brazilian Environmental Agency, demonstrating that this methodology is very suitable for determining any contamination by atrazine and ametryne residues in different samples, proving a good Substitute for mercury electrodes.