[Rapid determination of the ozone in water]

A new potassium iodide--N, N-diethy1-1,4-phenylen-ediammonium sulfate (DPD) spectrophotometry method for the determination of the ozone in water was established. The method was based on the quantitative reaction between the ozone and potassium iodide in buffered solution(pH 3.35): O3 + 2I- + 2H+-->O2 + I2 + H2O. Iodine could react with DPD regent and produce pink color. Its absorption was determined at 510 nm with spectrophotometer. The range of direct determination was 0-1.00 mg/L. Beer's law was obeyed in this range. The detection limit was 0.01 mg/L. The relative standard deviations were from 1.2% to 2.7% (n = 10). The recoveries were from 98.6% to 106.6%. Water samples were determined with both this method and iodimetry. The results were comparable. The method was applied to the determination of the ozone in water sample with satisfactory results. It was practical and reliable.