Determination of Sulfate Ion in Ferric Oxide Powder by Ion Chromatography

To establish a method for the determination of sulfate ion in ferric oxide powder by ion chromatography with suppression conductivity detector. The hydrochloric acid was used to decomposed samples, with 1.0 mmol/L sodium bicarbonate and 3.2 mmol/L sodium carbonate as mobile phase, and the flow rate was 0.7 mL/min, the colume temperature was 35 ℃, inject volumn was 20 μL. The results show that the sulfate had a good calibration linear ship in the range of 0.5～100 mg/L, the linear equation of sulfate was y=0.228 9x-0.038 3, R²=0.999 96. The recovery from 97.38% to 104.42%, RSD=1.01%, and the limit of detection was 0.002%. This method has the benefits of easy operation, highly sensitive, and good reproducibility. It can be used as a quality detection method of sulfate ion in ferric oxide powder.