Method for determining particular species of chlorine in a water sample

Abstract

A technique for determining and distinguishing between specific species of chlorine in a supply of water is disclosed herein along with certain applicable apparatus. In carrying out this technique, one or more water samples are obtained from a larger supply and made to display a pH within a specific range. In a preferred embodiment, a sample is provided for each of the different species of chlorine to be determined. A predetermined amount of hydrogen peroxide is added to each of these samples. If hypochlorous acid and/or hypochlorite (one of the species to be determined) is present in any of the samples, the hydrogen peroxide by itself will react therewith for producing oxygen. If however either monochloramine or dichloramine (other chlorine species) is present, it is necessary to combine the hydrogen peroxide with a certain minimum amount of iodine, preferably in the form of potassium iodide, to produce an oxygen evolving reaction. Dichloramine requires a greater concentration of iodine than monochloramine and, hence, the two can be distinguished from one another. In each case, the produced oxygen is detected for determining whether any or all of these chlorine species are present in the water supply and the amounts thereof.