Electrochemical detection of arsenite with silver electrodes in inorganic electrolyte and natural system mixtures

Journal of the Brazilian Chemical Society

National University of Córdoba¹  Rivas, Bernabe L.¹  University of Concepción, Concepción, Chile¹  Basáez, Luiz¹  Peña-Farfal, Carlos¹  Aguirre, María del C.¹ 

关键词: arsenite electrooxidation;    silver electrodes;    electrochemical detection;    tap water;   

DOI  :  10.1590/S0103-50532011001200018

学科分类：化学（综合）

来源: SciELO

【 摘 要 】

The electrochemical detection of arsenite with silver wire (SWE) or silver disc (SDE) electrodes was carried out in inorganic aqueous solutions, which are similar to those found under natural conditions. Cyclic voltammetry (CV), linear sweep voltammetry (LSV) and anodic stripping voltammetry (ASV) were applied. The investigated factors were pH, nature and concentration of supporting electrolyte and deposition time and voltage for ASV. The changes in the As(III) anodic peak current and potential in standard solutions (e.g., 0.1 mol L-1 Na2SO4, NaNO3, HNO3 and H2SO4) were evaluated. The neutral and basic media of inorganic salts were found to enhance the silver electrode sensitivity more than the acidic media. Thus, it was possible to work in alkaline medium with increased sensitivity for As(III) (limit of detection of 90 ng L-1). The improved analytical response made this system comparable to a nanoarray electrode. As the range of use of these electrodes was wide, SWE (area of 6.47 mm2) was applied to monitor tap water using 0.1 mol L-1 Na2SO4 as supporting electrolyte to successfully detect quantities above 0.5 mg L-1 As(III).

【 授权许可】

Unknown