This method describes how to determine the concentration of non-ionic surfactants in wastewater photometrically with a cuvette test.
Wastewater resulting from the industrial production of beer and other foods
Non-ionic surfactants (ethoxylate with 3–20 ether bridges) react with an indicator (TBPE: 3,3´,5,5´-tetrabromophenolphthalein ethyl ester, potassium salt) to form complexes which can be extracted with dichloromethane and are then measured photometrically.