应用化学 ›› 1987, Vol. 0 ›› Issue (3): 73-75.

• 研究简报 • 上一篇    下一篇

稀土离子选择电极在非线性响应区域响应特性及其数学模拟

李涵, 程毓渡, 吴金兰   

  1. 中国科学院长春应用化学研究所
  • 收稿日期:1985-08-16 修回日期:1986-07-16 出版日期:1987-06-10 发布日期:1987-06-10

ON THE CHARACTER OF RARE EARTH ION-SELECTIVE ELCTRODE IN THE NON-LINEAR RESPONSE REGION

Li Han, Cheng Yudu, Wu Jin1an   

  1. Changchun Institute of Applied Chemistry, Academia Sinica
  • Received:1985-08-16 Revised:1986-07-16 Published:1987-06-10 Online:1987-06-10

摘要: 离子选择电极(ISE)通常是基于能斯特响应来测定离子活度或浓度的。每一种ISE都存在着一个线性电位响应区域。为了满足线性响应的要求,待测组份浓度,介质酸碱度及共存的其它组份均受到较严格的限制。而许多实际体系(如混合稀土萃取体系)十分复杂,不仅待测组份浓度高,而且共存组份多,酸度变化也较大,电极在这类体系中常呈非线性响应。本工作报导CeO2膜稀土ISE在非线性响应区域对单一稀土和混合稀土的响应特性,和半经验数学模型的探讨。

Abstract: The character of cerium oxide membrane ion-selective electrode (ISE) for individual and mixed rare earth system in the non-linear response region has been investigated.The potential of the linear response region of ISE for HCl-CeCl3 system at pH=4.9-6.0 and rare earth conceniration (C)=10-2-10-5M can be described as: E=-30lgCCeCl-47.1 The relations of △E-C and △E-pH for HCl-PrCl3 system show that when pH<2 the interference is higher and the electrode can't be used for the measurement. The relations of △E-C for two rare earths mixed (Pr-Nd)Cl3 C=0.25-0.7M, four rare earths (La-Ce-Pr-Nd) Cl3 C=0.14-0.7M and fifteen rare earths (La-Lu) and Y C=0.2-1.0M systems in the presence of NH4Cl show that when pH≥ 2 the responses similar to those what in the individual rare earth, while pH<2 the interference of the acidity is evident. A general, more accurate model for various systems is proposed through mathmatical simulation: E=B1lg[Ci +B2(Ci+Cj)B2]