贵金属元素电分析化学研究(Ⅱ)——大量铱中微量铑的极谱溶出法测定

Electrochemical Studies of Noble Elements(Ⅱ)——Determination of Micro-Rhodium in the Macro Amount of Iridium by ASV

对于微量铑的电化学测定,一般多用极谱氢催化波法和示波极谱法。文献提出用伏安法测定Rh(Ⅲ),但灵敏度低,只能测至4×10^(-5)M。等在Hg_(2)(NO_(3))_(2)的1MHCl中得到了Rh(Ⅲ)的反相溶出峯,其灵敏度达10-7M,但未用于实际分析。

In this paper, the methods of separation macro-lridium and determination of micro-rhodium have been studied. By using home-made 15% of tri-(6,7,8)alkyl-phosphine oxide-benzene solution for extracting in 4N HC1, we have been successively separated the macro-lridum apart from micro-rhodium. The extraction rate for once lies in the range 97-99%.We have also found the optimum electrolytic system of 0.1N HC1-0.02N ethylene diamine-2.5 x 10-6M HgCl_(2)(pH= 1.4) for determination of micro amount of rhodium (Ⅲ) by anodic stripping voltammatry (ASV) on glass carbon electrode. The limit of detection as low as to 10 ppb may be achieved.