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锡合金微量铅的测定,一般采用光谱、原子吸收分析法和极谱分析法。化学分析一般采用双硫腙或PAP法。极普法需要汞,双硫腙或PAR法亦需极毒的氰化钾作掩蔽剂,四氯化碳或苯怍萃取剂。为了防止环境污染,本文论证了在不用氰化钾的前提下,二钾酚橙与铅生成络合物的最适宜酸度为PH5左右,残余锑锡和少量铅的最好掩蔽剂是氟化钾,铜铁锌采用抗坏血酸、亚铁氰化钾和硫脲联合掩蔽效果最佳。铅与二钾酚橙生成1:1的络合物,最大吸收波长为530mm,摩尔吸光系数ε=2.4×10~4,在0～50ug,/25ml铅符合比尔宅律,文中并用无铅的锡合金加铅的办法进行回收实验,证明本法具有准确度好,操作简便,不用剧毒试剂等特点。
Tin alloy trace lead determination, the general use of spectroscopy, atomic absorption spectrometry and polarographic analysis. Chemical analysis generally use dithizone or PAP method. Very general method needs mercury, dithizone or PAR method also need extremely toxic potassium cyanide as a masking agent, carbon tetrachloride or benzene extract extractant. In order to prevent environmental pollution, this paper demonstrates that the optimal acidity of dipotassium phenol orange and lead complex is about pH5 without using potassium cyanide, and the best masking agent of residual antimony and a small amount of lead is potassium fluoride , Copper, zinc and zinc ascorbic acid, potassium ferrocyanide and thiourea combined masking effect best. Lead and dipotassium phenol orange to form a 1: 1 complex, the maximum absorption wavelength of 530mm, the molar absorptivity ε = 2.4 × 10 ~ 4, 0 ~ 50ug, / 25ml lead complies with Bill Home Rule, Tin alloy plus lead recovery experiments show that the law has good accuracy, easy to operate, do not have highly toxic reagents and so on.