Abstract: In this work, the determination of micro-iridium by using anodic stripping voltammetry (ASV) after enrichment and separation with the synthetic ion exchange resin of thiopropionamide is studied. When pH=2, the resin can absorb 100% of Au(Ⅲ), Pd(Ⅱ), Pt(Ⅳ) and Ir(Ⅳ)ions from the hydrochloric acid solution. Then, when 20 mLof 6 mol/L HCl is used as an eluant, only iridium can be eluted quantitatively. Thus, the problem of.enrichment and separation of Ir from other interferring elements can be resolved. The authors investigated the conditions of determination of mi-cro-iridium by ASV without use of thin film mercury. 0. 3 mol/L HCl-0. 75μg Te⁴⁺/mL was selected as the supporting electrolytic system. The results show that the peak potential of Te(Ⅳ) is at +0. 45 V(vs SCE), whereas Ir(Ⅳ ) is at +0. 75 V, and the content of Ir(Ⅳ) is linear with peak current in the range of 10^-6～10^-8 g/mL. The detection limit reaches 20 × 10^-3 ppm.This method has been used for analysing some sample with good results agree with that of the original content. The recovery is in the range of 96%～104%.

Key words: Precious metal element, Iridium, Anodic stripping voltammetry