Voltammetric behavior and determination of bismuth on sodium humate modified carbon paste electrode

Abstract

Abstract The preconcentration and voltammetric behavior of Bi III on a sodium humate modified carbon paste electrode was studied by means of cyclic voltammetry (CV) and differential pulse stripping voltammetry (DPSV). The proposed measurement involves an initial nonelectrolytic preconcentration step in which Bi III is complexed by the surface modifier in a solution of 0.05 M KNO 3 ‐0.0106 M HNO 3 (pH 2.0) and a subsequent electrochemical scan step in which the preconcentrated Bi III was reduced and then oxidized promptly in supporting electrolyte of 0.5 M HNO 3 . The resulting DPSV anodic current was proportional to the concentration of Bi III ion over the range of 4.78 × 10 −8 –1.44 × 10 −5 M. The detection limit was 4.78 × 10 −8 M. The proposed method was used to determine bismuth in various samples. Various factors affecting the electrode behavior were also investigated at the same time.