氯化物中锂离子存在时EDTA质量滴定锶离子含量

EDTA Complex Mass Titration for the Content of the Strontium Ion Coexisting with Lithium Ion in Chlorite

中文关键词:  氯化锂  氯化锶  正丁醇  质量滴定  掩蔽滴定

英文关键词:Lithium chloride  Strontium chloride  n-Butanol  Mass titration  Masking titration

中文摘要:

      锂共存时对EDTA络合滴定Sr2＋离子产生较强的干扰，使分析结果偏高。根据被测液中氯化锂的大约含量，通过加入适量混合醇，可消除Li＋离子的干扰，质量滴定法相对误差〈0．3％。在锂锶质量比为0．100—14．5范围内。被测样中LiCl质量与加入混合醇体积呈线性关系。混合醇掩蔽体积范围为3～5mL。根据锂离子与水分子、短链醇形成蔟合物的键能，对消除Li＋离子干扰络合滴定的机理进行探讨。

英文摘要:

      It is well known that the presence of lithium would lead to significant errors in strontium measurements by EDTA titration methods. Depend on the content of lithium chloride in measured solution, the interference of Li＋ was eliminated and the analytical deviation of the mass titration was within 0. 3% by adding different amounts of the alcohol mixture to samples. When the mass ratio of lithium with strontium was 0. 100 between 14. 5 ,the mass of lithium chloride in the sample was presented linear relation to the volume of adding mixed alcohol. The dosage of the mixed alcohol volume was about 3 -5 mL. According to the binding energies of lithium ions to water molecule and short chain alcohol in cluster, the influence mechanism was discussed for removing the influence of Li ＋ on EDTA complexometric titration.