An Ultrasensitive Method for Detecting Picomolar Levels of Cadmium(II) by Fast-Scan Anodic Stripping Voltammetry

This work reported an approach for the determination of the heavy metal ion cadmium Cd(II) using a bismuth-film electrode (Bi-FE) with fast-scan anodic stripping voltammetry (FSASV). The experiment was divided into two steps. First, the Bi-FE was prepared by electrodepositing a metallic bismuth-film onto the electrode, and then the target metal ion Cd(II) was electrochemically preconcentrated on the Bi-FE. Second, the target metal was measured with FSASV. At a scan rate of 400 V/s, the anodic stripping peak current increased gradually with increasing Cd(II) concentration, and a linear relationship between the peak current and the logarithm of Cd(II) concentration was obtained from 0.1 μmol/L to 1.0 pmol/L, with a detection limit of 0.3 pmol/L (S/N=3). Furthermore, the method was successfully applied to detect Cd(II) in spiked tap water samples, with sufficient recoveries in the range of 94.0% to 105.2% and corresponding relative standard deviations ranging from 2.9% to 6.4%. Therefore, FSASV is a simple, rapid and ultrasensitive method for the detection of picomolar levels of Cd(II).