Photometric determination of anionic detergents. • Photometric determination with methylene blue. • Under suitable conditions anionic detergents react with methylene blue to form a coloured complex, which is extracted with an organic phase. Reference substance is methyl dodecylbenzene sulphonate (MBAS: 342 g/mol). • Type: standard test 1-32 • Range: 10 mm cuvette: 0.1 - 5.0 mg/l MBAS 50 mm cuvette: 0.02 - 1.00 mg/l MBAS • Sufficient for: 40 determinations • Sea water suitability: no