Batch and flow determination of uranium (VI) by adsorptive stripping voltammetry on mercury-film electrodes
Abstract
Uranium(VI) was determined by square wave adsorptive stripping voltammetry on a rotating-disc mercury-film electrode using 8-hdyroxyquinoline as a complexing agent (batch mode), or, alternatively, on a wall jet mercury-film electrode with cupferron as complexing agent (flow-through mode). For the flow-through configuration, the combination of a novel wall jet cell with an automated flow system and a commercial computer-controlled potentiostat allowed complete keyboard control of the sequence of operations. Both continuous flow and flow injection (FI) schemes for preconcentration were assessed, and various instrumental parameters are discussed. Linearity held typically for a concentration range of two orders of magnitude (for 60 s preconcentration). It was found that, whereas the batch and continuous-flow modes are more suitable for the determination of lower concentrations of UVI(<10–7 mol l–1), FI is ideal for higher concentrations (>10–7 mol l–1). The batch and flow methods were, finally, applied to the determination of UVI in a reference sea-water sample with accuracies of 7.2 and 4.2%, respectively, and relative standard deviations of 7.8 and 8.3%, respectively.