应用化学 ›› 1990, Vol. 0 ›› Issue (5): 83-85.

• 研究简报 • 上一篇    下一篇

钙镁和极弱酸的二次微分示波极谱滴定

翁筠蓉, 陈新文, 袁晓健, 高鸿   

  1. 南京大学化学系 南京 210008
  • 收稿日期:1989-11-17 修回日期:1990-01-10 出版日期:1990-10-10 发布日期:1990-10-10

SECONDARY DIFFERENTIAL OSCILLOGRAPHIC CHRONOPOTEN-TIOMETRIC TITRATION OF Ca,Mg AND VERY WEAK ACIDS

Weng Yunrong, Chen Xinwen, Yuan Xiaojian, Cao Hong   

  1. Department of chemistry, Nanjing University, Nanjing 210008
  • Received:1989-11-17 Revised:1990-01-10 Published:1990-10-10 Online:1990-10-10

摘要: 示波极谱滴定法有它独特的优点[1],但在某些测定中,终点指示的灵敏度尚有待进一步提高。例如,用EGTA(乙二醇二乙醚二胺四乙酸)和HEDTA(N-β羟基乙基乙二胺三乙酸)滴定Ca2+、Mg2+时,过量滴定剂的切口变化不够敏锐[2]。用强碱中和滴定极弱酸时,作为相应于pH≈11的指示剂的苯胺的切口变化不易判断。高次微分及电流反馈技术能克服这些缺陷。在(d2E/dt2)~E图上终点切口观察灵敏得多,Ca:Mg的比例可提高到100:1。在硼酸和苯酚测定中,测定下限较一次微分法降低了一个多数量级。

关键词: 微分示波极谱法, 计时电位滴定, 钙, 镁, 苯酚, 硼酸

Abstract: The secondary differential oscillographic chronopotentiometric titration has been carried out for Ca, Mg, boric acid and phenic acid determenition. The incision on the d2E/dt2 curves produced by the depolarizers is more sharp than that on the dE/dt-E curver. The indication of the end point of titration has been greatly improved.

Key words: differential oscillopollarography, chronoptentiometric titration, calcium, magnesium, phenol, boric acid