ADSORPTIVE STRIPPING MEASUREMENTS OF BISMUTH

A very sensitive stripping procedure for trace measurements of bismuth, based on the adsorptive accumulation of the bismuth-cupferron complex onto the mercury working electrode, is described. The optimized conditions include a sulfuric acid (5 x 10(-4) M) medium, containing 2.5 x 10(-5) M cupferron, and an accumulation potential of -0.10 V. Both voltammetric and potentiometric stripping modes can be employed to probe the reduction of the accumulated complex. The limit of detection after 10 minutes preconcentration is 6 ng L(-1) 3 x 10(-11) M), and the relative standard deviation at the 2 X 10(-8) M level is 1.6%. Most cations, including antimony do not interfere in the determination of bismuth. Simultaneous measurements of bismuth, titanium, and uranium are illustrated.