DIN 38408-3:2011-04

Ozone is primarily used for the treatment of water in order to produce potable or swimming pool water. Thereby, exact knowledge of ozone concentration in the water is necessary. Ozone concentration in the water decreases with time due to conversion with oxidizable substances and autocatalytic decomposition, for this reason the water sample is examined immediately after sampling. This standard specifies methods for determination of ozone in water. Iodometric determination of ozone applies for the determination of higher ozone concentrations. Two photometric methods are available for the determination of ozone in lower concentration ranges. The determination by means of (N,N) diethyl-p-penylenediamine (DPD) is based on a colour-forming reaction which can be disturbed by oxidation agents present in the water or formed during ozonation. These disturbances can be easier eliminated during the determination with the help of indigosulfonate. The standard has been prepared by Working Committee NA 119-01-03 AA "Wasseruntersuchung" ("Water Analysis") and been funded by the Länderfinanzierungsprogramm "Wasser, Boden und Abfall" (federal funding programme "Water, soil and waste").