贵金属元素电化学分析研究(Ⅻ)——离子交换富集分离阳极溶出伏安法测定微量铱

Studies on Electrochemical Analysis of Precious Metal Elements( Ⅻ) —— Determination of Micro-lridium by ASV After Enrichment and Separation with Ion Exchange

单独铱与其它贵金属和贱金属的有效分离方法仍属少见,作者采用15％三烷基氧化膦-苯溶液分离过大量铱,可达理想的效果,Shifris等成功地测定了Cu-Ni精矿中的铑与铱,支持电解质为0.5 mol/L HCl-0.1 mol/L Hg(Ⅱ),但其灵敏度。

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 mL of 6 mol/L HC1 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 HC1-0. 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%.