离子交换分离富集极谱法连续测定金、铂、铱、铑、钌

Simultaneous determination of Au,Pt,Ir,Rh and Ru by polarography after seperation and preconcentration by anion exchange resin

研究了在同一份试液中极谱法连续测定Au、Pt、Ir、Rh、Ru的体系。首先在1mol/L的氢氧化钠溶液中,于原点电位-0.20V处扫描作Au的峰电流-质量浓度曲线;然后,改变溶液pH值,在0.75mol/L硫酸-1.5%氯化铵-1.5×10-3mol/L六次甲基四胺-0.003%硫酸肼体系中,于原点电位-0.78V处扫描作Pt、Ir、Rh的峰电流-质量浓度曲线;最后,加入2.25mol/L硫酸-4%氯化铵-2.5×10-4mol/L硫脲测定Ru。在选定的实验条件下得到令人满意的分析结果,线性范围分别为:0.1～1000μg/mL(Au);8×10-5～6.4×10-3μg/mL(Pt、Ir);1.6×10-5～1.28×10-3μg/mL(Rh);1.14×10-4～3.42×10-3μg/mL(Ru)。实际样品通过阴离子交换树脂分离富集后进行分析,回收率在93%～106%之间。

In this article,the condition of the system and instrument for the simultaneous determination of Au,Pt,Ir,Rh and Ru in the same solution by polarography is studied.The analysis technological process is as follows： first,the current-mass concentration curve of Au is scanned at the origin potential of-0.20 V in the medium of 1 mol/L NaOH solution;and then pH is adjusted,the current-mass concentration curves of Pt,Ir and Rh are determined at the origin potential of-0.78 V in the systemmofm 0.75 mol/L H2SO4-1.5 % NH4Cl-1.5 × 10 -3 mol/L （ CH2） 6N4-3 ×10 -3% N2H4·H2SO4;finally,Ru is determined by adding 2.25 mol/L H2SO4-4 % NH4Cl-2.5 × 10 -4 mol/L thiocarbamide.This method is used for geological sample analysis with good results in the selected experimental conditions.The linear ranges of Au,Pt,Ir,Rh and Ru are respectively 0.1-1 000 μg/mL（ Au） ,8 × 10 -5-6.4 × 10 -3 μg/mL（ Pt,Ir） ,1.6 × 10 -5-1.28 × 10 -3 μg/mL（ Rh） and 1.14 × 10 -4-3.42 × 10 -3 μg/mL （ Ru） .Usually,the samples are analyzed after seperation and preconcentration by anion exchange resin and the recovery range is from 93 % to 106 % .