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本文研究了大量铟存在下能测定镉和铜的一系列支持电解质,研究了用JP—M1型脉冲极谱仪的仪器参数,用示波极谱仪研究了铟、镉、铜等离子的氧化电位和还原电位,了解了控制电解电位可排出大量铟对镉、铜的干扰,还研究了底液各成份浓度和镉、铜峰电流大小的关系及干扰离子影响情况。通过研究确定了在测定高纯金属铟中痕量镉和铜时先在5NHBr介质中用异丙醚萃取分离主体元素后,用0.5M乙二胺——0.5MKOH——5×10~(-5)MHg(NO_3)_2底液,在-1.1伏电解富集2分钟即可测定2毫微克/毫升的镉和铜。如改变仪器参数或增加富集时间可达更高的灵敏度,得出的波形良好,再现性好,此法操作简便、快速、测定样品中镉和铜的相对标准偏差<10％,镉的回收率92—98％,铜的回收率为69—103％,准确度符合要求。
In this paper, a series of support electrolytes capable of measuring cadmium and copper in the presence of a large amount of indium were studied. The oxidation potential of indium, cadmium and copper ions was studied by oscillopolarography with the instrument parameters of JP-M1 pulse-polarography And reduction potential. It is understood that controlling the potential of electrolysis can expel a large amount of indium on the interference of cadmium and copper. The relationship between the concentration of each component and the current of cadmium and copper and the influence of interfering ions are also studied. Through the research, it was confirmed that when the trace elements cadmium and copper in the high purity metallic indium were determined, the main element was extracted with 5 ml of isopropyl ether in 5NHBr medium and then treated with 0.5M ethylenediamine - 0.5MKOH - 5 × 10 ~ (- 5) MHg (NO_3) _2 bottom solution, enrichment at -1.1 volts for 2 minutes to determine 2 ng / ml of cadmium and copper. Such as changing the instrument parameters or increasing the enrichment time up to higher sensitivity, the resulting waveform is good, good reproducibility, this method is simple and rapid, the determination of the relative standard deviation of cadmium and copper samples <10%, cadmium recovery The rate of 92-98%, the recovery rate of 69-103% copper, accuracy to meet the requirements.