碘量法测定铜时配位体缓冲溶液的应用

碘量法测定铜时配位体缓冲溶液的应用 THE APPLICATION OF LIGAND BUFFER SOLUTION IN DETERMINATION OF COPPER BY IODOMETRY 王志铿 Wang Zhikeng Zhao Zaofan first-author 赵藻藩 < 正 > 配位体缓冲溶液是Tanaka[1]提出的一种络合缓冲体系。目前,它在光度分析中应用较多。我们曾研究了有关配位体缓冲溶液的理论[2] 和在酸碱滴定中的应用[3]。本文报告碘量法测定铜时配位体缓冲溶液的应用。采用通常的碘量法（NH 4 HF 2 法）测定铜时,一般需加NH 4 HF 2 掩蔽Fe 3+ ,这将带来两个缺点:1,NH 4 HF 2 对玻璃的腐蚀和对环境的污染;2,试样中碱土金属离子的含量较高时,由于所产生的氟化物沉淀对铜的吸附作用,致使测定结果偏低。对此,文献[4]曾提出用1:1的Z n 2+ -EDTA作为配位体缓冲溶液代替NH 4 HF 2 掩蔽Fe 3+ 。我们在此项工作的基础上作了较深入的研究。由配位体缓冲溶液理论可知,较理想的情况是:K FeY 》K MY 》K CuY 。我们试验表明,虽然K ZnY (10 16·5 < K CuY (10 18· ),但仔细考察一下,便会发现只要在Zn 2+ -Z n Y中保持适当大比例的游离Z n 2+ 量,就有可能较完全的掩蔽Fe 3+ ,而不致影响 The applieation of Ligand buffer solution Zn-EDTA as masking ageut in determination of copper by iodometry has been examined theoretically and practically. The acidity of solution, the amount and ratio of Ligand buffer solution and the influences of foreign ions have been studied. Proposed the optimumn conditions for titration of copper. Good results has been obtained in analysis of ore and alloy samples. 1981-03-01 2021-04-01 3