Will chlorine interfere with the indigo ozone method?
Chlorine interference with ozone testing.
Chlorine concentrations up to 10 mg/L will not interfere with the indigo ozone method (method 8311). The Ozone AccuVac® Ampuls contain a masking agent (malonic acid) to account for up to 10 mg/L chlorine. Concentrations greater than 10 mg/L will cause high results. Addition of malonic acid directly to the sample to prevent interference from >10 mg/L chlorine is not recommended, as erroneous results may be obtained.