AUTOMATED-SYSTEM FOR ONLINE ADSORPTIVE STRIPPING VOLTAMMETRIC MONITORING OF TRACE LEVELS OF URANIUM

An automated system for on-line monitoring of trace uranium, based on a flow-through adsorptive stripping operation, is described. The on-line formation of the uranium-oxine complex is followed by its adsorptive accumulation and voltammetric quantitation at the downstream working electrode. About 10-60 runs can be made every hour with high reproducibility (RSD of 3-5%) and a detection limit of 0.7-mu-g/L. The dependence of the peak current on different experimental variables is reported. The sequence of events involved in the adsorptive stripping voltammetric cycle is controlled by a computer. Analogous on-line monitoring of chromium(VI) are also reported with 36 runs/h (2.1% RSD), and detection limit of 1.5-mu-g/L. The system holds great promise for field-based operation.