Determination of Cd and Cu at ppb level in water samples by Anodic Stripping Voltammetry (ASV). An interactive lab experiment.

Abstract

In this exercise, the content of cadmium and copper in a water sample is determined by Anodic Stripping Voltammetry (ASV) and the Standard Additions Method (SAM). First, the experimental conditions of the determination are specified. 25 mL of water sample is pipetted and its pH value is adjusted by addition of acetic-acetate buffer. Anodic Stripping Voltammetry is carried out on the first sample. The analysis is then repeated on the same sample with successive additions of 50 microliters of 5 ppm standard solution of Cd(II) and Cu(II). The voltammograms are obtained in all cases and the peak intensity (average of three determinations) is plotted against the amount of metal added. Two graphs (for Cd and Cu) are obtained and fitted to linearity by least squares. The equations allow to calculate the amount of Cd and Cu in the sample. The data are randomly generated.