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极谱法同时测定Pb、Sn一直是较难解决的分析课题。极谱溶出法同时测定Pb、Sn的困难主要是:二者在大多数酸性支持电解质中峰电位相近,Cu与Sn易生成金属互化物而使Sn峰受到严重干扰。当Cu量足够大时,Sn峰将受到抑制,甚至完全不出峰。陈毓麒等和汪尔康均采用变换底液办法得到良好分开的Pb、Sn溶出峰。本文采用预先将干扰元素Cu等用萃取法分离除去,然后在同一支持电解质中,直接进行Pb~(2+)、Sn~(4+)连续测定。
Polarographic determination of Pb and Sn simultaneously has been a difficult analytical problem. The difficulties of simultaneous determination of Pb and Sn by polarographic dissolution are mainly that the peak potentials of the two are similar in most acidic supporting electrolytes and the intermetallics of Cu and Sn are prone to cause serious interference with Sn peak. When the amount of Cu is large enough, the Sn peak will be suppressed, or even no peak at all. Chen Yuqi et al and Wang Erkang are used to transform the bottom solution to get a good separation of Pb, Sn dissolution peak. In this paper, the interference element Cu and so on were separated and removed by the extraction method in advance, and then Pb ~ (2 +) and Sn ~ (4+) were directly measured in the same supporting electrolyte.