采用自动电位滴定法标定硫酸铈溶液,并进行硫酸亚铁片中铁含量的测定。自动电位滴定法以电位突跃监测终点,在45 ℃~50 ℃之间,以草酸钠溶液标定硫酸铈溶液,测定值的相对标准偏差(n=5)为0.070%。取硫酸亚铁片1片用0.01 mol·L-1硫酸溶液30 mL溶解,直接用硫酸铈溶液滴定测定铁含量。方法用于硫酸亚铁片样品分析,回收率为100%,测定值的相对标准偏差(n=5)在1.2%~2.6%之间。

Automatic potentiometric titration method (APTM) was applied to the calibration of ceric sulfate solution and ferrum in ferrous sulfate tablets was determined by APTM. The end-point of titration was measured with potential jump by APTM. Value of RSD (n=5) found was 0.070% for calibration of ceric sulfate with sodium oxalate solution at temperatures between 45 ℃ and 50 ℃. A ferrous sulfate tablet was dissolved with 0.01 mol·L-1 sulfuric acid solution (30 mL) and titrated directly with ceric sulfate solution for determination of ferrum. The proposed method was applied in the analysis of samples of ferrous sulfate tablets, giving values of recovery of 100% and RSD′s (n=5) in the range of 1.2%-2.6%.