Determination of Pb(II) and Cd(II) via anodic stripping voltammetry using an in-situ bismuth film electrode. Increasing the sensitivity of the method by the presence of Alizarin Red S

Abstract

Using the differential pulse anodic stripping voltammetry technique and an in-situ bismuth film deposited on a glassy carbon electrode, a simple and sensitive method for rapid Pb(II) and Cd(II) quantification was developed. The effect of the presence of Alizarin Red S (ARS) was studied, and an increase in the sensitivity of the method was obtained. The developed method was compared to another reported method that uses a 0.1 mol L-1 acetate buffer medium (pH 4.5). The optimal experimental conditions are listed as follows: [CH3COOH]: 30.0 mmol L-1; [Bi(III)]: 0.75 mg L-1; [ARS]: 40.0 mu mol L-1; [Fe(CN)64-]: 50.0 mu mol L-1; Edep: -1.40 V; tdep: 60 s. Under these conditions, the detection limits were 0.16 and 0.09 mu g L-1 and the linearity was maintained at values as great as 30.0 and 15.0 mu g L-1 for Pb(II) and Cd(II), respectively. The effect of 35 foreign ions as possible interferents was studied. The method was validated using two certified reference materials (TMDW and TMDA-61.3) with satisfactory results. Finally, the method was applied for the analysis of four natural water samples.