Studies of selectivity in the amaranth method for chlorine dioxide

Studies were designed to evaluate the amaranth method for measuring chlorin e dioxide in water. Specifically, the effects of pH and temperature are exa mined for the amaranth method. The results of interference studies are repo rted for free available chlorine species, chlorite ion, chlorate ion, iron (III) ion, oxidized manganese, and monochloramine. Additional research focu sed on selectivity enhancement for chlorine dioxide over free available chl orine using ammonia/ammonium chloride buffer and gas diffusion-flow injecti on analysis. The results of method detection Emit and accuracy and precisio n studies are reported for measuring chlorine dioxide in the presence of fr ee available chlorine. (C) 2000 Elsevier Science B.V. All rights reserved.