Precise determination of iridium by neutron activation analysis coupled with internal standard method

Instrumental neutron activation analysis with internal standard correction was applied for precise determine of mg quantities of Ir in high-purity IrBr₄. A known amount of Au standard solution was used as an internal standard to compensate for inhomogeneity of the neutron flux through an irradiation capsule and for neutron self-shielding. The linearity of the calibration curves of Ir was improved by using an internal standard. The relative expanded uncertainty (k = 2) associated with the determined value was 0.86%, which allowed the mg quantities of iridium to be precisely determined. (author)