Estudo da técnica de voltametria adsortiva de redissolução anódica, empregando o eletrodo DDB para detecção de metais

Abstract

The discharge of potentially toxic metals in water bodies has promoted significant changes in behavior harmful physical, chemical and biological receptor body. The detection of these contaminants with adequate selectivity, sensitivity, and reprodutibility is essential for reliable methods and required to determine these metal ions. The voltammetry of stripping are important electrochemical techniques in trace metals analysis. There is no study of the adsorptive anodic stripping voltammetry (AdASV) technical for in the current literature the determination of metal ions, using the Boron Doped Diamond Electrode (BDD). This study aimed to carry out a study on the determination of metals in aqueous medium using the BDD electrode with AdASV technique the supporting electrolyte selected was Britton - Robinson buffer 0,04 M, pH (1-11), and EDTA as chelating agent. For the Study of adsorptive process on the electrode surface DDB, voltammetric behavior of the complexes Fe-EDTA, Cu-EDTA and Zn-EDTA were analyzed and being possible to observe the oxidation processes related to Fe2+, Cu2+ and Zn2+, the methodology Technical AdASV was optimized by varying the following parameters: Deposition time (Td), deposition potential (Ed), frequency (f) and amplitude (a). Calibration curves were prepared for certain metals and found values for the detection limits LD and limits of quantification LQ. As LD: 0,005 ppm for Fe2+, Cu2+ 0,002 ppm and 0,02 ppm for Zn2+. LQ: 0,019 ppm for Fe2+, Cu2+ to 0,007 and 0,07 to Zn2+. After optimization of technical parameters, triplicate tests were carried out with real samples of the stream of forty in Manaus-AM, Brazil, the concentrations found through the methodology proposed for certain metals were: 0,09 ppm for Fe2+, 0,24 ppm Cu2+ and 0,06 ppm Zn2+. The results obtained with the optimization of the parameters of the voltammetric technique and detection in real sample showed that it is possible to use the BDD electrode for detecting metals in aqueous solution by the technique AdASV