EN ISO 7393-2:2018 Water quality - Determination of free chlorine and total chlorine - Part 2: Colorimetric method using N@N-dialkyl- 1@4-phenylenediamine@ for routine control purposes
This document specifies a method for the determination of free chlorine and total chlorine in water@ readily applicable to lab- and field-testing. It is based on measurement of the absorption@ the red DPD colour complex in a photometer or the colour intensity by visual comparison of the colour with a scale of standards that is regularly calibrated. This method is appropriate for drinking water and other waters@ where additional halogens like bromine@ iodine and other oxidizing agents are present in almost negligible amounts. Seawater and waters containing bromides and iodides comprise a group for which special procedures are to be carried out. This method is in practice applicable to concentrations@ in terms of chlorine (Cl2)@ from@ for example@ 0@000 4 mmol/l to 0@07 mmol/l (e.g. 0@03 mg/l to 5 mg/l) total chlorine. For higher concentrations@ the test portion is diluted. Commonly@ the method is applied as a field method with mobile photometers and commercially available ready-for-use reagents (liquid reagents@ powders and tablets). It is essential that those reagents comply with minimum requirements and contain the essential reagents and a buffer system suitable to adjust the measurement solution to a pH range of typically 6@2 to 6@5. If there is doubt that water samples have uncommon pH values and/or buffer capacities@ the user has to check and@ if necessary@ to adjust the sample pH to the required range. The pH of the sample is within the range of pH 4 and 8. Adjust@ if necessary@ with sodium hydroxide solution or sulfuric acid before the test. A procedure for the differentiation of combined chlorine of the monochloramine type@ combined chlorine of the dichloramine type and combined chlorine in the form of nitrogen trichloride is presented in Annex A. In Annex C@ a procedure is presented for the determination of free and total chlorine in drinking and other low polluted waters@ for disposable planar reagent-filled cuvettes using a mesofluidic channel pump/colorimeter.
EN ISO 7393-2:2018 history
2018EN ISO 7393-2:2018 Water quality - Determination of free chlorine and total chlorine - Part 2: Colorimetric method using N@N-dialkyl- 1@4-phenylenediamine@ for routine control purposes
2000EN ISO 7393-2:2000 Water Quality - Determination of Free Chlorine and Total Chlorine - Part 2: Calorimetric Method Using N,N-Diethyl-1,4-Phenylenediamine, for Routine Control Purposes