Calibration of Ceric Sulfate Solution and Determination of Fe in Ferrous Sulfate Tablets by Automatic Potentiometric Titration Method

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%.