Development of a sequential injection anodic stripping voltammetry (SI-ASV) method for determination of Cd(II),...

This paper describes the development and validation of a sequential injection (SI) anodic stripping voltammetry (ASV) method using the hanging mercury drop electrode for accumulation of the heavy metal cations Cu(II), Pb(II) and Cd(II). The method was applied to wastewater samples after proper acid digestion in open vessels to eliminate matrix effects. For a deposition time of 90 s at the flow rate of 10 microl s(-1), the detection limits of the method were 0.06, 0.09 and 0.16 micromol L(-1) for Cd, Pb and Cu, respectively. Under these conditions the linear dynamic range was between 0.20 and 9.0 micromol L(-1) and the sampling frequency was 30 analyses per hour. The relative standard deviation of the method was 3%(n=7) at the concentration level of 2.0 micromol L(-1). The accuracy of the method was evaluated by spiking the samples with known amounts of the metal cations, and by comparison with an independent analytical technique, the inductively coupled plasma atomic emission spectroscopy (ICP-AES). Average recoveries were around of 84%, and the results showed no evidence of systematic errors in comparison to the ICP-AES.