Kationische Tenside im Abwasser und Belebtschlamm

In waste water and activated sludge, cationic surfactants are often measured as disulfine blue active substances. Because of the suspectibility of this method to interfering substances a more specific and sensitive method using HPLC with a conductivity detector is presented. Anionic and nonionic surfactants are extracted together with the cationics, and influence the chromatographic process of the cationic surfactants. Hence it becomes difficult to quantify them. The changed chromatographic behaviour is attributed to micelle formation, which can be different for individual HPLC-systems. Only after further purification of the extract are reproducible measurements of the cationic surfactants possible.