用毛细管电泳法测钠离子

Determination of the content of Na^+ by Capillary Electrophoresis

Co(HAC)2和Mn(HAC)2是生产精对苯二甲酸(PTA)的催化剂,为节约Co(HAC)2用量,近年来在主装置上增加了催化剂回收系统。该系统利用草酸与Co2+反应生成草酸钴沉淀来回收Co2+,并加入Na(OH)中和过量的草酸,减少腐蚀。因此Na+成为PTA生产装置必须检测的一个重要项目。文章研究了用毛细管电泳法测定Na+的方法、条件、干扰及回收率。试验结果表明:该方法的回收率在98.4%～103.3%,样品中的常见阳离子Co2+、Mn2+、Fe3+、Cr2+、Ni2+不干扰测定,样品中可能存在的有机溶剂PX对Na+的测定有正干扰,可以通过在制作工作曲线的标准溶液中加入相应量的PX来消除干扰,HAC对Na+的测定无干扰。

Co（HAC） 2 and Mn（HAC） 2 are used as catalyst in the product of PTA. In recent year, in order to save cobalt, recovery system was assembled into PTA equipment. The recovery system uses the truth that oxalic acid can react with Co （HAC）2 and form cobalt oxalate deposition product, so to recovery cobalt . In the same time, some NaOH added in recovery system to neutralize the excess oxalic acid. So the content of Na^＋ became an impotent control item. This paper discussed how to determine the content of Na^＋ by Capillary Electrophoresis. The result showed this method is accurate, simple, and the recovery is in the range of 98.4%- 103.3%. some usual positive ion Co^（2＋） , Mn^（2＋）, Fe^（3＋）, Cr^（2＋）, Ni^（2＋）have no interference. And possible-existent PX solvent in sample has positive interference, but this positive interference can be removed by the aid of adding same content PX in standard solution that used to form working curve.