以离子水合能解释离子选择电极响应机理  

Interpretation on the Response Mechanism of Ion-Selective Electrode with Ion-Hydration Free Energy

作　　者：史生华[1] 尹世伟[1] 郭艳丽[1] 高鸿[1] 

机构地区：[1]西北大学分析科学研究所,西安710069

出　　处：《分析化学》2002年第9期1025-1029,共5页Chinese Journal of Analytical Chemistry

摘　　要：用相继切换不同浓度I- 试液的活度阶梯法研究了碘化银基离子选择电极 (I- ISE)的瞬时响应。随电位变化的离子水合自由能ΔGh(I- )显示出 |ΔGh(I- ) |越小 ,正活度阶梯电位跃迁越快而负活度阶梯电位变化越慢。将 -ΔGh(I- )看作I(H2 O) -n 与I- ISE表面反应的活化能解释了这个现象。比起传统电位法 ,活度阶梯法的主要优点是ISEs响应非常快并且更灵敏 ,有可能实现小体积试液的快速分析。The transient response of iodide ion-selective electrode (ISE) was studied by means of activity step method switching different concentrations of I- test solution one after another. The ion-hydration free energy DeltaG(h) (I-) changing with potential shows that the smaller the \DeltaG(h) (I-)\ the faster the potential jump in positive activity step while the slower the potential change in negative activity step. That -DeltaG(h) (I-) was considered as the activation energy in the reaction of I (H2O)(n)(-) with I- -ISE surface explained this phenomenon. The principal advantage of activity step method over the conventional potentiometry is that ISEs response is much faster and more sensitive, and able to achieve fast analysis of test solution in small volume.

关 键 词：离子选择电极 电极响应机理 活度阶梯法 壁式喷嘴 瞬时电位法 离子水合自由能 

分 类 号：O646.5[理学—物理化学]