Screen-printed carbon electrodes bulk-modified with Bi2O3 OR Sb2O3 for trace determination of some heavy metals

Abstract

Screen-printed carbon electrodes (SPCE) bulk-modified with Bi.2O3 or Sb2O3 have been investigated for their suitability to determinate some selected heavy metals using anodic stripping voltammetry. At a SPCE modified with 1.25% (w/w) Bi2O3, the corresponding re-oxidation peak potentials appeared at -0.785 V for Cd, or at -0.565 V for Pb. At a SPCE modified with 1.00% (w/w) Sb2O3, the reoxidation peak of Cd appeared at -0.805 V. Bulk-modified Bi2O3 -SPCEs, after an electrochemical preconditioning, can be used for monitoring Cd and Pb at concentrations with a preconcentration time of 600 s at -1.2 V vs.SCE. An analogous Sb2O3 -SCPE displays a higher quantification limit for Cd at the same conditions, whereas the determination of Pb seemed impossible by simple procedures. The SPCE modified with Bi2O3 was applied for determination of Pb(II) in drinking water and urine.