【摘要】 <正> 离子选择电极分析中,为了消除液接电位导致的误差,可利用另一离子电极作为参比电极,只要在试液中保持该离子的活度恒定即可。采用同价态离子电极互作参比电极时,能以标准比较法测定试液中相应离子的活度或浓度比,还可用标准加入法或Gran作图法分别测定相应离子的浓度。标准加入法不必考虑加入的标准液的稀释影响,直接用下式计算。更多还原

【Abstract】 The evaluating formulas of double standard addition of identical volumes and successive standard addition method with equipotential change in the cells without liquid Junction where two kinds of ion-selective electrodes with similar slopes are used as reference electrode and sensitive electrode respectively are introduced. The dependence of relative error on the volumes of the addition for the method of equipotential change is discussed. In these methods, both two ion concentrations may be determined continuously and their concentrations before and after the addition of the standards should be within their own limit of linear response of the electrodes respectively. The examples of natrium, potassium, chloride and fluoride in brine show that these methods are simple and rapid. The precision of equipotential change method is higher than that of the equal-volume method.更多还原