DIN 38409-23:2010-12

The group of surface-active substances consists, in addition to anionic (methylene blue active) and cationic substances, of non-ionic (bismuth active) substances. Surface-active substances act as emulsifiers, wetting or dispersing agents during the manufacturing processes in important sectors, such as textile industry and agricultural chemistry. In addition, they are increasingly being used for the production of water-based paints and varnishes and for applications of emulsion polymerization. Amongst others, surface-active substances are used for the production of polymers, which are used in paints and varnishes, paper, textiles, floor wax and adhesives. In the domestic, commercial and industrial sectors, surfactants (especially from detergents and cleaning agents) may enter the waste water. The new edition of the 1980 edition of standard DIN 38409-23 is now available for the determination of bismuth active substances. DIN EN 903 "Water quality - Determination of anionic surfactants by measurement of the methylene blue index MBAS (ISO 7815-1:1984, modified); German version EN 903:1993") contains a revised version for the determination of methylene blue substances. The method is applicable to non-ionic surfactants of the alkylphenol and alcohol-alkylene oxide adduct, as far as they are purgeable and precipitable with Dragendorff reagent. The standard has been prepared by Working Committee NA 119-01-03 AA "Wasseruntersuchung" ("Water Analysis") and been funded by Länderfinanzierungsprogramm "Wasser, Boden und Abfall" (federal funding programme "Water, soil and waste").