On the interference of 210Pb in the determination of 90Sr using a strontium specific resin

We investigated the interference of radiolead in the isolation of radiostrontium using a strontium-specific resin by means of 85Sr and 212Pb radiotracers. The resin was found to be almost equally specific for lead ions as well. Elution of Pb2+, however, was found to occur at very low acid concentrations (£0.02 M HNO3) of the elutant. Even with pure distilled water as the elutant, elution of lead cannot compete with strontium, due to the delayed elution dynamics caused by residual acid in the column. In contrast to strontium, which is eluted quickly from the column and almost quantitatively after 4 mL elutant (practically independently of the acid concentration of the elutant), lead is eluted with much delay and not completely after the 10 mL elution. The Eichrom method for the determination of radiostrontium in water proposes elution with 0.05 M HNO3, which was found extremely useful, because at such an acid concentration, no radiolead is eluted from the column and allows the production of a pure radiostrontium fraction which can be measured by liquid scintillation counting.