Functionalised resin-modified carbon paste sensor for the voltammetric determination of Pb(II) within a wide concentration range

A carbon paste electrode bulk-modified with a functionalised macroporous resin is described as a voltammetric sensor for Pb(II) ions. The commercially available product, QuadraPure™TU, admixed into the paste at a ratio of 30% (v/v), contains thiourea residues that act as a highly effective functional group for chelating Pb(II). By combining with square-wave anodic voltammetry and “open-circuit” accumulation, the stripping peak of lead in 0.1 M acetate buffer could be calibrated over a wide concentration range of 0.005–5 mg l−1 Pb, with possible extension up to 25 mg l−1, when the signal of interest was not seriously affected by the presence of other common metals. Applicability of the sensor in practical analysis has been tested on selected water samples or a certified reference material and the respective results agreed well to those obtained by ICP-MS and to the content declared.