ABSTRACT
Objective In order to evaluate the quality and performance of chlorine dioxide disinfectant,it is necessary to develop a set of methods to determine the components in chlorine dioxide disinfectant.Methods Iodometry,malonic acid iodometry,improved malonic acid iodometry and five-step iodometry were employed to determine the components including ClO_2, Cl_2,ClO_2~-,and ClO_3~-in chlorine dioxide disinfectant,the advantages and disadvantages of the test methods were compared.Results Using iodometry,the liquid stabilized chlorine dioxide products activated by hydrochloric acid,the content of ClO_2 was 20.23 mg/ml that was accord with the content which was marked in the product label.Using malonic acid iodometriy,the liquid stabilized chlorine dioxide contents of ClO_2 was 19.99 mg/ml,Cl_2 was 0.35 mg/ml,in which a little chlorine was detected.Using improved malonate iodometry and five-step iodometry,the activation rates of the liquid stabilized chlorine dioxide products were 88.0% and 75.6% respectively,ClO_2 and ClO_2~-in the liquid stabilized chlorine dioxide products could be distinguished.Conclusion Active chlorine dioxide and residual ClO_2~-can be detected by using iodometriy and improved malonic acid iodometry,but iodometriy and malonic acid iodometry can not.