Adsorptive stripping voltammetry of trace uranium: Critical comparison of various chelating agents

A critical and systematic evaluation of four chelating agents for adsorptive stripping voltammetric measurements of trace uranium is reported. The utility of propyl gallate (PG) and N-benzoyl-N-phenylhydroxylamine (BPA) is illustrated for the first time and compared to that of previously used cupferron and oxine. All ligands offer convenient quantitation of low μg/l uranium concentrations, following short adsorption times. The sensitivity pattern is: PG>cupferron>oxine>BPA. A large difference in the selectivity (in the presence of co-existing metals) is observed, according to the following selectivity order: PG∼cupferron>BPA>oxine. Applicability to rapid assays of groundwater and sediments is illustrated. Such comparison of the analytical performance of various ligands should serve as a guide for selecting the most appropriate adsorptive stripping scheme for other target metals