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The adsorptive collection of the aluminum complex with cupferron is exploited for developing a highly sensitive stripping procedure for trace aluminum. Optimal experimental conditions include the use of 2 × 10−4M cupferron in PIPES buffer (pH 7.0), an accumulation potential of −0.40 V and a linear potential scan. With controlled accumulation for 2 min, a detection limit near 30 ng/l. aluminum is obtained. The relative standard deviation (at 5 μg/l.) is 2.9%. Possible interferences are evaluated. The analytical performance compares favourably with that of early adsorptive stripping schemes for aluminum.

Trace levels of uranium can be determined by stripping voltammetry after controlled adsorptive preconcentration of the uranium—cupferron complex on the mercury electrode. The resulting procedure greatly improves the selectivity over previously reported adsorptive stripping schemes, while offering similar (subnanomolar) detection limits. In addition, the use of cupferron eliminates interference from dissolved oxygen, extends the linear range, and offers a wider useful pH range. Both potentiometric and voltammetric stripping approaches are used to follow the reduction of the adsorbed complex. The effect of various experimental parameters is explored. Adaptation to flow-through cells permits on-line monitoring of trace levels of uranium at rates of 30–60 samples h −1 , with relative standard deviations of 2.7–4.1%. Applicability to the quantitation of uranium in ground water samples is demonstrated.