采用电位滴定法同时标定硫酸高铈标准溶液和硫酸亚铁铵标准溶液。以草酸钠为基准物质,通过对电位滴定装置的改进,在被滴定溶液与盐桥之间增加了一个一端封有磺酸型离子膜、内部注入2 mol·L-1硫酸溶液的玻璃管,用来阻隔盐桥与被滴定溶液间的物质交换。方法用于硫酸高铈和硫酸亚铁铵溶液的标定,测定值的相对偏差为0.55%,表明方法具有高精度。

The standard solutions of Ce(SO4)2 and (NH4)2Fe(SO4)2 were standardized simultaneously by potentiometric titration. Sodium oxalate was used as primary standard. In order to avoid the interference of mass exchange between the salt bridge and the measured solution with the result of titration, the titration device was modified. An ion-exchange membrane was set between the salt bridge and measured solution to depress the mass exchange at the interface. It was found that high precision was attained by the present method, giving values of relative deviation between the determined values of the 2 standard solution of 0.55%.