Desenvolvimento de metodologia eletroanalítica para determinação de Cu, Fe e Zn em água empregando eletrodo de diamante dopado com boro

Abstract

Copper, iron and zinc were electroanalytically quantified by anodic stripping voltammetry coupled with square wave voltammetry (ASV/SWV) and boron doped diamond (DDB) electrode. An electroanalytical methodology were developed where parameters were optimized for metals determination. Determination of all metals was performed in KCl 1 mol.L-1 solution. Cyclic voltammetry analysis showed both metals oxidation and reduction peaks with quasi-reversible characteristic. Parameters of the ASV were equal for all metals except the deposition potential (Edep) that were for cooper -0,2 V ; -1,8 V for zinc and - 0,1 V iron. The deposition time and equilibration time was 180 s and 60 s respectively. Regarding SWV parameters, it was diverse for each metal, for cooper frequency (f) and amplitude (a) values were 60 Hz and 70mV, for zinc 70 Hz and 80 mV, for iron 70 Hz and 90 mV, respectively. After parameters optimization analytical curves were constructed for each metal and calculated the detection limits which resulted in 0,005; 0,12 and 0,16 ppm for cooper, zinc and iron respectively. The methodology developed for detection of these metals was applied in water samples taken from the Igarapé do Quarenta located in industrial district of Manaus, the analysis showed good repeatability and low error when compared with results obtained by atomic absorption spectroscopy.