Pneumatoamperometric determination of chlorine in water

Free chlorine in water can be determined by acidifying the water sample, purging it with nitrogen and determining the chlorine present in the nitrogen stream with a gold porous electrode. The current response of gold porous electrode is related to the concentration of free chlorine by using a calibration curve. This pneumatoamperometric method gives results fully comparable to the standard o-toluidine photometric method used for water supplies. It is uninfluenced by the presence of other dissolved oxidants and requires only one milliliter of sample.