在酸性介质中用氟电极测定氟离子的新方法

A new method for determination of fluoride ion using a fluoride elestrode in an acidic medium

基于弱酸根离子在不同酸度溶液中的化学平衡和离子选择电极的响应特征, 本文推导出了以氟电极为指示电极, 玻璃pH电极作参比在酸性介质中测定氟的新方法. 经验证： 当pH＜2时, 氟离子浓度在10^-2～10^-5 mol/L范围内, 电池电动势值与氟离子总量呈能斯特响应, 试液中少量铝的存在对测定不构成干扰. 用该法直接测定了酸蚀法铝型材废水中的氟, 加标回收率达96%～98%.

Based on both the equilibrium of the weak acidic ion in the different acidic solutions and the response characteristics of ion-selective electrode, in this paper a new method for determining content of fluoride ion was proposed with the glass electrode as the reference electrode and the fluoride electrode as the indicator-electrode. It was demonstrated that the potential has a Nerstian response towards the concentration of fluoride ion in the range of 10^-2 - 10^-5 mol/L with pH 〈 2, and that the results was independent of the presence of micro amount of aluminum. Using this method, the fluorine content in the wastewater of aluminum bar processing was determined and the recoveries of standard addition were 96 % - 98 %.