Biological Evaluation of Methods for the Determination of Free Available Chlorine.

摘要

The purpose of this study was to develop a biological referee procedure (biofac) for the qualitative and quantitative determination of free chlorine in solutions containinfg compounds that may interfere with the colorimetric chemical methods and to use this procedure to compare the specificity of the DPD, FACTS, amperometric, and electrode procedures for free chlorine. The bacterial virus f2 was chosen as the test organism for the development of the biofac procedure, since f2 is resistant to inactivation by combined chlorine and sensitive to free chlorine. A linear, reproducible, relationship was found between the rate of f2 inactivation and free chlorine concentration at pH 6.0 and 7.0. This relationship was used as a standard curve for the determination of free chlorine concentration from the rate of f2 inactivation. Specificity of the tests for free available chlorine was determined by comparison of the level of free chlorine indicated by the test to the level indicated by the biofac procedure. A false positive result was defined as an indication of free chlorine by the test in the absence of viricidal activity. (Author)