Carbon paste electrode modified with thiourea-functionalized resin for determination of lead

Abstract

In this contribution, a carbon paste electrode modified with thiourea-functionalised resin is described in terms of its electroanalytical characterisation and applicability to the determination of Pb2+ ions. Commercial macroporous resin, QuadraPure(TM)TU, added to the carbon paste mixture in an amount of 30% (v/v), contains thiourea residual groups being able of effectively complexing the Pb2+ ions. When using the SWV mode in combination with open-circuit accumulation, intermediate electrolytic reduction, and subsequent anodic stripping step, the resultant signal for lead could be calibrated within a very wide concentration range of 5–25 000 μg L−1 Pb2+, with a limit of detection (3 sigma) of about 1 μg L−1, and without serious interferences from other heavy metal ions as confirmed in special studies. Practical usefulness of the method has been tested on selected water samples and the respective results verified by means of recovery rates, certified reference material, and ICP-MS reference determinations.