COMPARATIVE ANALYTICAL METHODS FOR THE

Four commercially available methods used for the analysis of low-level Chlorine Dioxide (ClO2) concentrations in drinking water were evaluated for accuracy and precision and ranked according to cost, efficiency and ease of the methods under several conditions that might be encountered at water treatment plants. The different analytical methods included: 1. The DPD (N, N-diethyl-p-phenylenediamine) method 2. Lissamine Green B (LGB) wet-chemical method 3. Palintest ® kit LGB 4. Amperometric titration All these tests were performed with standard 1.0 mg/L ClO2 either alone or in the presence of different chlorine species, including chlorite ion (ClO2-, 0.5 mg/L), chlorate ion (ClO3-, 0.5 mg/L) and chlorine (Cl2, 1.0 mg/L). The tests were performed with four different matrices, with different concentrations of 0.1 mg/L ClO2, 0.5 mg/L ClO2 and 1.0 mg/L ClO2 at a constant temperature of 20oC and at different temperatures of 0oC, 10oC and 20oC at a fixed ClO2 concentration of 1.0 mg/L