用Oxine作释放剂选择性螯合滴定法测定钙镁  

SELECTIVE CHELATOMETRY DETERMINATION OF CALCIUM AND MAGNESIUM USING OXINE AS RELEASING AGENT

作　　者：王献科[1] 李玉萍[1] 

机构地区：[1]兰州市东岗镇钢厂

出　　处：《中国钼业》1996年第6期37-40,共4页China Molybdenum Industry

摘　　要：干扰离子如Ｆｅ３＋、Ａｌ３＋、Ｃｕ２＋、Ｎｉ２＋、Ｚｒ４＋、Ｚｎ２＋、Ｍｏ６＋、Ｃｄ２＋、Ｐｂ２＋、Ｍｎ２＋等，用适量Ｔａｒｔｒａｔｅ、ＴＥＡ、ＤＬ－Ｃｙｓｔｅｉｎｅ掩蔽。在ｐＨ１０左右，用ＥＤＴＡ滴定Ｃａ２＋、Ｍｇ２＋，确定合量。然后加入Ｏｘｉｎｅ分解Ｍｇ－ＥＤＴＡ螯合物，释放出的ＥＤＴＡ用Ｃａ２＋标准溶液滴定。用ＭＴＢ－ＸＯ－ＣＰＢ为混合指示剂，终点颜色变化敏锐，一般常见金属离子均不干扰。该法已用于测定水和工业废水中钙镁含量。The interference of cations such as Fe 3+ 、Al 3+ 、Cu 2+ 、Ni 2+ 、Zr 4+ 、Zn 2+ 、Mo 6+ 、Cd 2+ 、Pb 2+ 、Mn 2+ etc are suitably masked with tartrate TEA DL Cysteine as masking agent The Ca 2+ and Mg 2+ is first titrated at pH10 with EDTA standard solutions to determine the sum of the two metal ions Oxine is then added to decompose the Mg EDTA chelates and the liberated EDTA is back titrated at pH10 with Ca 2+ standard solution,with MTB XO CPB as mixed indicator The change of end point is more sensitive,normally metal ions were found not to interference The method has been for the determination of Ca and Mg in water and industrial wast water with satisfactory results

关 键 词：钙 镁 释放剂 螯合滴定法 

分 类 号：O614.2[理学—无机化学] O655.25[理学—化学]