极谱法测定锡的研究  

The Study on Determination of Tin by Polarometry

作　　者：王铭 WANG Ming(Kunming Metallurgical Research Institute,Kunming,Yunnan 650031,China)

机构地区：[1]昆明冶金研究院,云南昆明650031

出　　处：《云南冶金》2018年第4期79-82,共4页Yunnan Metallurgy

摘　　要：在酸性底液中,Pb^(2+)极谱峰电位为-0.47 V,Sn^(2+)、Sn^(4+)都为-0.5 V(vs.SCE),峰电流重叠严重。实验选择适当的硫酸酸度,加入一定量的EDTA、氯化钡、硫酸钾,既保证Pb完全沉淀,又防止Sn沉淀。针对样品溶解后既有Sn^(2+)也有Sn^(4+),而且两个价态的锡占比没有规律,无法测定,选择三氯化铁把锡完全氧化为稳定的Sn^(4+),测定时加入抗坏血酸除去多余的Fe3+,防止在电极反应过程中产生的Sn^(2+)再被氧化为Sn^(4+)。实验也证明:电极反应是分步进行的推论。锡的浓度在0.02~200 mg/L线性良好。In the acid base solution, Pb^2＋ polarographic peak electric potential is -0.47V, Sn^2＋ , Sn^4＋ , which voltage is - 0.5V （ vs. SCE） , the peak current overlapped seriously. The proper acidity of sulfuric acid shall be selected in the lab, and a certain EDTA, barium chloride, potassium sulphate shall be added, which can guarantee the complete precipitation of Pb, and can prevent precipitation of Sn. Once the sample dissolves, both Sn^2＋ and Sn^4＋ are contained, two valence stated tin ratio has no regulation, it cannot be measured, so ferric trichloride is selected to stabilizes Sn^4＋ by complete oxidation of tin, and the ascorbic acid is added to remove the redundant Fe^3＋ during determination, which can prevent Sn^2＋ oxidated to Sn^4＋ again in the electrode reaction process. The experiment also proved： the electrode reaction shall be carried out step by step. The linear is good when tin concentration is 0.02 - 200mg/L.

关 键 词：极谱法 锡 测定 

分 类 号：O657.14[理学—分析化学]