A radiometric procedure for the micro determination of palladium and iodide with iodine-131

Abstract

A method is described for the micro determination of palladium and iodide in which the radioisotope iodine-131 is used as a tracer.

The principle of the method depends on the formation of labelled palladium(II) iodide by the addition of an excess of a solution of potassium iodide containing iodine-131 to the palladium, the palladium(II) iodide being then carried by zirconium hydrogen orthophosphate, Zr(HPO₄)₂, formed in the solution. From the loss of iodine-131 by the solution, the amount of palladium can be determined. By using the same principle, iodide can be determined if a known amount of palladium is added. The adsorption of palladium(II) iodide by zirconium hydrogen orthophosphate has been found to be selective.

Amounts of palladium in the range 4 × 10^–3 to 2 × 10^–7 g have been determined so far, and errors are always within statistical fluctuations in activity measurements.

The effect of the presence of some foreign ions has also been studied. The method is simple and can be completed within 30 minutes.