离子选择性电极多次标准加入法测量氟离子电极电势

Potentiometric Measurement of F - with Ion selective Electrodes by Multiple Standard Addition Method

建立了选择性电极中离子传递的模型。活化后的离子选择性电极 ,在电极表面形成活化层 ,阳离子和等量的阴离子分布在电极活化层的两侧 ,离子由溶液与活化层的界面经活化层传递到固定组成膜与活化层界面。在一定的条件下 ,电极膜电势随时间的变化与溶液和活化层的界面离子浓度随时间的变化成正比。在控制电势随时间的变化率基本恒定的情况下 ,方法被用于手工测量氟离子选择性电极电势 ,电极斜率。溶液离子浓度直接由 Gran方程求解。

A model of ion transport in activated layer and diffuse layer was proposed. Variations of the potential φ of electrode membrane with the ion concentration were studied. The positive charges and an equal number of negative charges are lined up at the interface of the activated layer. The whole arrangement is like a parallel plate capactor. It was found that on certain conditions the rate of potential φ change increased with the rate of ion concentration change at the interface of the activated layer and the diffuse layer. Based on this theroy, the method was used to measure the potenitial of a fluoride ion selective electrode,and the slope and ion concentration were directly derived by Gran equation.