Simultaneous DPAdSV for Heavy Metals Determination in the Seawater of a Former Bauxite Mining Area

The widespread use of HMDE for multi-ionic analysis is mainly explained by the following factors: excellent reproducibility, due to the electrode surface ease of renewal, for preventing hysteresis; wide Ec; ability to forming amalgams with many redox-active metal ions; and (sub)nanomolar detection limits, which have unique capabilities for multi-metal determination. In this research, selectivity and sensitivity for Pb, Cd and Zn simultaneous determination, by DPAdSV, using HMDE as WE and CCA as a ligand, were tested. This method is based on the deposition of CCA-metals on Hg electrodes. The instrumental and chemical parameters that could improve measurements were obtained under optimal conditions, including: CCA concentration (0.05 mmol/L), pH (7), Edep (-0.3 V) tdep (60 s), AB concentration (0.5 mol/L), scan rate (150 mV/s), pulse height (80 mV), Hg drop size (4 mm2) and linearity (Ip vs concentration), which was in the range from 5 to 170, 5 to 140 and 5 to 190 M, for Pb, Cd and Zn, respectively). The LOD (S/N = 3) values were 0.05, 0.03 and 0.05 mu g/L for Pb, Cd and Zn, respectively. The repeatability and intermediate precisions were tested as RSD of 0.44, 1.21 and 1.23% for Pb, Cd and Zn, respectively. The recovery values were 98, 99 and 101% for Pb, Cd and Zn, respectively. As result, the DPAdSV method with CCA ligands was successfully applied for heavy metals determination in the seawater of a former bauxite mining area.