Determination of Chlorine Dioxide, Chlorine, Chlorite, and Chlorate in Water

This article describes a procedure for either amperometric or potentiometric determination of iodine formed by the oxidation of iodide by chlorine dioxide, chlorine, chlorite, and chlorate. Either phenylarsine oxide or sodium thiosulfate can be used as the titrant. Sample pretreatment and pH adjustment are used to differentiate among the various chlorine species.